Research

BCAAs

75 peer-reviewed studies curated from PubMed and Semantic Scholar.

5
Meta-analyses
2
Systematic reviews
66
RCTs
2
Other studies
Meta-analyses (7%)
Systematic reviews (3%)
RCTs (88%)

Studies

Sorted by quality and recency

2025·Archives of gerontology and geriatrics·Haoran Li, Runfa Zhang, Yongye Ma, et al

Effects of branched-chain amino acid-rich nutritional supplements combined with resistance training on body composition and body function in older patients with sarcopenia.

Meta-analysisn = 459Physical Performance

This meta-analysis evaluated the effects of combining resistance training with BCAA-rich supplements on body composition and function in older adults with sarcopenia. The analysis included 12 randomized trials with 459 participants. Results showed that the combined intervention significantly improved the skeletal muscle index but did not significantly affect other functional or body composition outcomes.

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2024·Clinical nutrition ESPEN·Elham Sobhy, Mohamed Mahmoud Kamal, Yasmin Saad, et al

Effect of branched-chain amino acid supplementation and exercise on quadriceps muscle quantity and quality in patients with cirrhosis as assessed by ultrasonography: A randomized controlled trial.

RCTn = 220Physical Performance Nutrition

RCT of 220 liver cirrhosis patients assessing the effect of BCAA supplementation and exercise on quadriceps muscle quantity and quality. Interventional groups showed significant improvements in muscle thickness, echo intensity, strength, performance, and nutritional status. Combined BCAA and exercise had the best results in Child-Pugh B patients.

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2024·Sports medicine - open·Atef Salem, Khouloud Ben Maaoui, Haithem Jahrami, et al

Attenuating Muscle Damage Biomarkers and Muscle Soreness After an Exercise-Induced Muscle Damage with Branched-Chain Amino Acid (BCAA) Supplementation: A Systematic Review and Meta-analysis with Meta-regression.

Systematic reviewRecovery Physical Performance

This systematic review and meta-analysis investigated the effects of BCAA supplementation on muscle damage biomarkers and muscle soreness after exercise-induced muscle damage. BCAA supplementation significantly reduced creatine kinase levels and delayed onset of muscle soreness at various time points post-exercise, but had no significant effect on lactate dehydrogenase levels.

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2021·Amino acids·Martim Gomes Weber, Silas Seolin Dias, Tarlyson Regioli de Angelis, et al

The use of BCAA to decrease delayed-onset muscle soreness after a single bout of exercise: a systematic review and meta-analysis.

Meta-analysisRecovery

Systematic review and meta-analysis of BCAA supplementation on delayed-onset muscle soreness (DOMS) after exercise-induced muscle damage. Ten RCTs were included, with seven studies showing BCAA reduced DOMS after 24 to 72 hours. BCAA was found useful for improving muscle recovery in trained subjects at low doses for mild to moderate EIMD.

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2020·Zhonghua yi xue za zhi·W X Xue, F Yang, J J Duan, et al

[Effect of oral administration of branched-chain amino acids supplementation on the mortality of patients with hepatocellular carcinoma: a meta-analysis].

Meta-analysisn = 1,179Longevity

Meta-analysis of 14 studies with 1,179 patients investigating the effect of BCAA supplementation on mortality in hepatocellular carcinoma patients. BCAA supplementation significantly reduced 3-year and 5-year mortality rates, particularly in patients undergoing radiofrequency ablation, but had no significant effect on 1-year mortality or in hepatectomy patients. BCAA also increased albumin levels, suggesting improved liver reserve function.

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2019·Nutrition and cancer·Bartholomew P McKay, Annabel L Larder, Vincent Lam

Pre-Operative vs. Peri-Operative Nutrition Supplementation in Hepatic Resection for Cancer: A Systematic Review.

Systematic reviewn = 725

Systematic review comparing pre-operative and peri-operative nutritional supplementation on post-operative outcomes in hepatic resection for cancer. BCAA supplementation reduced overall complication rate by 26.9% in one cohort study, while pre-operative immunonutrition reduced post-operative ascites by 25.4% in another. Enteral supplementation showed no benefit for post-operative complications.

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2025·Scientific reports·Tomoko Hasegawa, Hanako Ohashi Ikeda, Hiroyasu Abe, et al

Post hoc analysis of a randomized placebo-controlled trial suggests potential visual benefits of branched-chain amino acids in retinitis pigmentosa.

RCTn = 70

Post hoc analysis of a randomized placebo-controlled trial assessing branched-chain amino acids (BCAAs) in patients with retinitis pigmentosa. The study found that the TK-98 group showed slower decrease rates of total point score and mean deviation in visual-field tests compared to placebo, suggesting potential visual benefits.

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2024·Nutrition journal·Yimei Ma, Xining Zhao, Yan Pan, et al

Early intravenous branched-chain amino acid-enriched nutrition supplementation in older patients undergoing gastric surgery: a randomized clinical trial.

RCTn = 137Nutrition

This randomized clinical trial assessed the effect of early supplementation with a branched-chain amino acid-enriched formula on postoperative outcomes in older patients undergoing gastric surgery. The treatment group had a shorter standardized length of hospital stay, better gastrointestinal function, and less weight loss compared to the control group.

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2023·BMC gastroenterology·Sith Siramolpiwat, Nisakorn Limthanetkul, Bubpha Pornthisarn, et al

Branched-chain amino acids supplementation improves liver frailty index in frail compensated cirrhotic patients: a randomized controlled trial.

RCTn = 54Physical Performance Nutrition

RCT evaluating 16 weeks of branched-chain amino acids (BCAA) supplementation in frail compensated cirrhotic patients. The BCAA group showed significant improvements in liver frailty index, BMI, serum albumin, skeletal muscle index, and quality of life compared to control.

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2021·Nutrients·Delicia Shu Qin Ooi, Jennifer Qiu Rong Ling, Fang Yi Ong, et al

Branched Chain Amino Acid Supplementation to a Hypocaloric Diet Does Not Affect Resting Metabolic Rate but Increases Postprandial Fat Oxidation Response in Overweight and Obese Adults after Weight Loss Intervention.

RCTn = 111Physique

RCT with 111 overweight and obese Chinese adults examining the effect of BCAA supplementation on resting metabolic rate and substrate utilization during a weight loss intervention. BCAA supplementation did not significantly affect resting metabolic rate but increased postprandial fat oxidation response.

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2021·Respiratory medicine·Claire de Bisschop, Fabrice Caron, Pierre Ingrand, et al

Does branched-chain amino acid supplementation improve pulmonary rehabilitation effect in COPD?

RCTn = 60Physical Performance -

RCT involving 60 COPD patients to assess the effect of BCAA supplementation during a 4-week pulmonary rehabilitation program. Both BCAA and placebo groups showed improvements in exercise capacity, muscle performance, quality of life, and dyspnea, but BCAA supplementation did not provide additional benefits over placebo.

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2019·International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition·Michael V Fedewa, Steven O Spencer, Tyler D Williams, et al

Effect of branched-Chain Amino Acid Supplementation on Muscle Soreness following Exercise: A Meta-Analysis.

Meta-analysisn = 61Recovery

Meta-analysis examining the effect of BCAA supplementation on delayed onset muscle soreness (DOMS) following exercise. The analysis included 8 studies with 61 participants and found that BCAA supplementation significantly reduced DOMS compared to placebo.

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2015·Alimentary pharmacology & therapeutics·G-Q Zhu, K-Q Shi, S Huang, et al

Systematic review with network meta-analysis: the comparative effectiveness and safety of interventions in patients with overt hepatic encephalopathy.

Meta-analysisBrain Health

Systematic review and network meta-analysis comparing interventions for overt hepatic encephalopathy (OHE), including L-ornithine-L-aspartate, BCAA, and others. L-ornithine-L-aspartate and BCAA significantly improved clinical efficacy compared to observation. L-ornithine-L-aspartate showed a trend towards being the most effective intervention, with significant reduction in blood ammonia concentration. Neomycin was associated with more adverse events.

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2025·Journal of gastrointestinal and liver diseases : JGLD·Trang Thu Nguyen, Linh Thuy Nguyen, Shigeru Yamamoto, et al

Comparison of Effectiveness Between Protein and BCAA in Late Evening Snack on Vietnamese Liver Cirrhotic Outpatients: a Randomized Clinical Trial.

RCTn = 32Nutrition

RCT comparing the effectiveness of a protein snack versus a BCAA snack in 32 Vietnamese liver cirrhosis outpatients. The protein group showed significant improvements in albumin levels and ALT liver enzyme reduction, while the BCAA group did not. Both groups showed increased Chronic Liver Disease Questionnaire scores.

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2025·American journal of men's health·Kebin Meng

Effect of Timing of Branched-Chain Amino Acid Supplementation on Muscle Recovery after Resistance Training in Healthy Males.

RCTn = 24Recovery Inflammation

This double-blind randomized controlled trial investigated the effects of pre- and post-exercise BCAA supplementation on muscle recovery and inflammation in 24 untrained male college students. Post-exercise BCAA supplementation significantly reduced muscle soreness and inflammatory markers (IL-6 and CRP) compared to placebo and pre-exercise supplementation, but did not affect neuromuscular recovery.

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2025·Nutrients·Chenglin Luan, Yizhang Wang, Junxi Li, et al

Branched-Chain Amino Acid Supplementation Enhances Substrate Metabolism, Exercise Efficiency and Reduces Post-Exercise Fatigue in Active Young Males.

RCTn = 11Physical Performance Recovery

In a double-blind cross-over RCT, eleven active males completed exercise tests after supplementation with BCAAs or placebo. BCAA supplementation enhanced fat oxidation during constant load exercise, increased carbohydrate oxidation and exercise efficiency during time to exhaustion, and reduced immediate post-exercise fatigue.

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2024·Journal of neurotrauma·Daniel J Corwin, Sage R Myers, Kristy B Arbogast, et al

Head Injury Treatment With Healthy and Advanced Dietary Supplements: A Pilot Randomized Controlled Trial of the Tolerability, Safety, and Efficacy of Branched Chain Amino Acids in the Treatment of Concussion in Adolescents and Young Adults.

RCTn = 42Brain Health Physical Performance

Pilot RCT evaluating the efficacy, tolerability, and safety of BCAA supplementation in concussed adolescents and young adults. No difference in processing speed was found, but there was a significant reduction in total symptom score and an increase in return to physical activity with higher doses of BCAAs. No serious adverse events were reported.

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2024·European journal of applied physiology·Kurt A Escobar, Trisha A VanDusseldorp, Kelly E Johnson, et al

The biphasic activity of autophagy and heat shock protein response in peripheral blood mononuclear cells following acute resistance exercise in resistance-trained males.

RCTn = 20

This study investigated the autophagic and heat shock protein responses to acute intense lower body resistance exercise in peripheral blood mononuclear cells with and without BCAA supplementation in 20 resistance-trained males. BCAA supplementation did not affect the autophagy or HSP70 response, which were upregulated following exercise.

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2024·Nutrients·Lotte L K Nielsen, Max Norman Tandrup Lambert, Jørgen Jensen, et al

The Effect of Ingesting Alginate-Encapsulated Carbohydrates and Branched-Chain Amino Acids During Exercise on Performance, Gastrointestinal Symptoms, and Dental Health in Athletes.

RCTn = 10Physical Performance Recovery

RCT comparing the effects of carbohydrate hydrogels with and without branched-chain amino acids (BCAAs) on cycling performance and recovery in 10 trained male cyclists/triathletes. The BCAA-containing hydrogel (ALG-CP) improved time-to-exhaustion performance and reduced heart rate and muscle damage markers compared to other formulations.

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2022·Nutrients·Takaaki Matsuda, Hiroaki Suzuki, Yoko Sugano, et al

Effects of Branched-Chain Amino Acids on Skeletal Muscle, Glycemic Control, and Neuropsychological Performance in Elderly Persons with Type 2 Diabetes Mellitus: An Exploratory Randomized Controlled Trial.

RCTn = 36Physical Performance Mood

A 24-week RCT evaluated the effects of 8 g BCAA supplementation versus 7.5 g soy protein on skeletal muscle, glycemic control, and neuropsychological performance in 36 elderly individuals with T2D. Skeletal muscle mass and HbA1c did not change significantly, but knee extension strength increased in the soy protein group and tended to increase in the BCAA group. Depressive symptoms improved in the BCAA group, though not significantly different between groups.

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2022·Journal of the International Society of Sports Nutrition·Yosuke Tsuchiya, Kenichi Yanagimoto, Norihiko Sunagawa, et al

Omega-3 fatty acids enhance the beneficial effect of BCAA supplementation on muscle function following eccentric contractions.

RCTn = 29Physical Performance Recovery

This double-blind, placebo-controlled study investigated the effects of BCAA and fish oil supplementation on muscle damage from eccentric contractions in 29 untrained males. The BCAA+FO group showed significantly higher MVC torque immediately after ECCs compared to placebo, while both BCAA and BCAA+FO groups had greater ROM and lower muscle soreness than placebo.

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2021·Nutrients·Adriana Caldo-Silva, Guilherme Eustáquio Furtado, Matheus Uba Chupel, et al

Effect of Training-Detraining Phases of Multicomponent Exercises and BCAA Supplementation on Inflammatory Markers and Albumin Levels in Frail Older Persons.

RCTn = 35Inflammation Physical Performance Brain Health

This study investigated the effect of a 40-week multifactorial intervention combining multicomponent exercise and BCAA supplementation on inflammatory markers and albumin levels in frail older persons. The ME plus BCAAs group showed improvements in cognitive profile, muscle strength-related albumin levels, and a reduction in TNF-α levels, although no significant changes were observed for TNF-α/IL-10 ratio or MPO activity.

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2021·The American journal of gastroenterology·Marta Hernández-Conde, Elba Llop, Lucía Gómez-Pimpollo, et al

Adding Branched-Chain Amino Acids to an Enhanced Standard-of-Care Treatment Improves Muscle Mass of Cirrhotic Patients With Sarcopenia: A Placebo-Controlled Trial.

RCTn = 32Physical Performance

A pilot, prospective, randomized, double-blind study of 32 cirrhotic patients with sarcopenia assessed the effect of BCAA supplementation on muscle mass. The BCAA group showed significant improvement in muscle mass compared to placebo. The study also noted improvements in the Liver Frailty Index and zinc levels.

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2021·International heart journal·Kozo Hotta, Ryoji Taniguchi, Hiroyuki Nakayama, et al

The Effects of an Oral Nutritional Supplement with Whey Peptides and Branched-Chain Amino Acids for Cardiac Rehabilitation of Patients with Chronic Heart Failure.

RCTn = 20Heart Health Physical Performance

This randomized, parallel-group comparative pilot study evaluated the effects of an oral nutritional supplement with whey peptides and branched-chain amino acids on cardiac rehabilitation in 20 CHF patients. The supplement increased fat mass and exercise capacity, suggesting it may be a useful treatment for CHF patients.

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2021·Journal of nutritional science and vitaminology·Noritada Yoshikawa, Motohisa Yamamoto, Akiko Kuribara-Souta, et al

Amino Acid Profile in 18 Patients with Rheumatic Diseases Treated with Glucocorticoids and BCAAs.

RCTn = 18Physical Performance

RCT involving 18 patients with rheumatic diseases treated with glucocorticoids, assessing the effect of BCAA supplementation on muscle mass. BCAA supplementation increased serum creatinine and albumin levels, decreased ammonia and urinary 3-methylhistidine levels, and correlated positively with improvement in biceps femoris muscle atrophy.

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2020·Experimental gerontology·Reza Bagheri, Scott C Forbes, Darren G Candow, et al

Effects of branched-chain amino acid supplementation and resistance training in postmenopausal women.

RCTn = 30Physical Performance -

RCT involving 30 postmenopausal women to assess the effects of BCAA supplementation and resistance training on muscle mass, strength, and regulatory factors. Both placebo and BCAA groups showed significant increases in muscle mass and strength, with no additional benefit from BCAA supplementation.

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2020·Journal of science and medicine in sport·Faizal A Manaf, Jeremiah J Peiffer, Garth L Maker, et al

Branched-chain amino acid supplementation improves cycling performance in untrained cyclists.

RCTn = 18Physical Performance

RCT investigating the effects of acute BCAA supplementation on cycling performance in 18 recreationally active men. BCAA supplementation reduced time-to-completion and ratings of perceived exertion, while increasing heart rate, but did not affect neuromuscular parameters.

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2017·Revista de gastroenterologia de Mexico (English)·A Ruiz-Margáin, R U Macías-Rodríguez, S L Ríos-Torres, et al

Effect of a high-protein, high-fiber diet plus supplementation with branched-chain amino acids on the nutritional status of patients with cirrhosis.

RCTn = 72Nutrition

An open, randomized clinical trial evaluated the effect of a high-protein, high-fiber diet plus BCAA supplementation on the nutritional status of 72 patients with cirrhosis over 6 months. The BCAA group showed an increase in muscle mass and a decrease in fat mass, with no significant changes in ammonia or glucose levels, indicating the safety of the intervention.

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2016·Nutrition (Burbank, Los Angeles County, Calif.)·Shunsuke Nojiri, Kei Fujiwara, Noboru Shinkai, et al

Effects of branched-chain amino acid supplementation after radiofrequency ablation for hepatocellular carcinoma: A randomized trial.

RCTn = 51Stress

RCT examining the effects of oral BCAA supplementation on liver function, intrahepatic recurrence rate, and complications after radiofrequency ablation for hepatocellular carcinoma. The BCAA group showed fewer complications, higher event-free survival, lower intrahepatic recurrence rate, and improved mental stress scores compared to the control group.

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2012·Surgery today·Kengo Ichikawa, Takehiro Okabayashi, Hiromichi Maeda, et al

Oral supplementation of branched-chain amino acids reduces early recurrence after hepatic resection in patients with hepatocellular carcinoma: a prospective study.

RCTn = 56Longevity

Prospective RCT assessing the effect of oral BCAA supplementation on liver tumorigenesis after hepatic resection in HCC patients. The BCAA group showed a significantly lower recurrence rate at 30 months post-surgery and decreased tumor markers compared to the control group.

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2010·Amino acids·Takehiro Okabayashi, Miho Iyoki, Takeki Sugimoto, et al

Oral supplementation with carbohydrate- and branched-chain amino acid-enriched nutrients improves postoperative quality of life in patients undergoing hepatic resection.

RCTn = 96Nutrition

A prospective randomized clinical trial with 96 patients undergoing hepatic resection assessed the impact of oral supplementation with BCAA-enriched nutrients on postoperative quality of life. The BCAA group showed significant improvement in quality of life and preserved liver function compared to the control group.

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2009·Hepato-gastroenterology·Daiki Habu, Shuhei Nishiguchi, Shinji Nakatani, et al

Comparison of the effect of BCAA granules on between decompensated and compensated cirrhosis.

RCTn = 65Nutrition

Randomized trial of 65 patients with HCV-related cirrhosis to assess the effect of BCAA granules on serum albumin levels. BCAA supplementation was effective in maintaining serum albumin levels in patients with decompensated cirrhosis and compensated cirrhosis with lower BTR, but not in compensated cirrhosis with higher BTR.

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2009·Journal of nutritional science and vitaminology·Yoshiharu Shimomura, Hisamine Kobayashi, Kazunori Mawatari, et al

Effects of squat exercise and branched-chain amino acid supplementation on plasma free amino acid concentrations in young women.

RCT

The study examined the effects of squat exercise and BCAA supplementation on plasma free amino acid concentrations in young, untrained female subjects. BCAA supplementation increased plasma BCAA concentrations post-exercise, while methionine and aromatic amino acids were temporarily decreased compared to placebo.

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2024·Nutrients·J. Ballesteros-Torres, Anayansi Escalante-Aburto, María Elena Villarreal-Arce, et al

Exploring the Impact of Protein Supplement Source on Body Composition in Women Practicing Anaerobic Resistance Exercise: A Pilot Study

StudyPhysique

Pilot study on the impact of different protein supplements on body composition in women practicing anaerobic resistance exercise. BCAAs and vegan supplements significantly decreased body weight, while meat protein resulted in a higher BMI compared to BCAAs. No significant changes in muscle mass were observed after eight weeks.

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2019·The American journal of clinical nutrition·Cas J Fuchs, Wesley J H Hermans, Andrew M Holwerda, et al

Branched-chain amino acid and branched-chain ketoacid ingestion increases muscle protein synthesis rates in vivo in older adults: a double-blind, randomized trial.

RCTn = 45Physical Performance

A double-blind, randomized trial comparing the effects of ingesting 6 g BCAA, 6 g BCKA, and 30 g milk protein on muscle protein synthesis rates in older males. All groups showed increased early myofibrillar protein synthesis rates, but only the milk protein group maintained elevated rates during the late postprandial phase.

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2019·Asia Pacific journal of clinical nutrition·Takashi Ikeda, Yuki Matsunaga, Masanori Kanbara, et al

Effect of exercise therapy combined with branched-chain amino acid supplementation on muscle strength in elderly women after total hip arthroplasty: a randomized controlled trial.

RCTn = 31Physical Performance

RCT of 31 elderly women post-total hip arthroplasty comparing BCAA supplementation combined with exercise to control. BCAA group showed significant improvement in knee extension strength and upper arm cross-sectional area, but not in hip abductor muscle strength.

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2018·Nutrients·Trisha A VanDusseldorp, Kurt A Escobar, Kelly E Johnson, et al

Effect of Branched-Chain Amino Acid Supplementation on Recovery Following Acute Eccentric Exercise.

RCTn = 20Recovery Physical Performance -

This RCT investigated the effect of BCAA supplementation on recovery from eccentric exercise in 20 males. BCAA supplementation reduced muscle soreness at 48 and 72 hours post-exercise but did not significantly affect creatine kinase levels, vertical jump, or jump squat performance compared to placebo.

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2018·American journal of cardiovascular drugs : drugs, devices, and other interventions·Yuichi Uchino, Masafumi Watanabe, Munenori Takata, et al

Effect of Oral Branched-Chain Amino Acids on Serum Albumin Concentration in Heart Failure Patients with Hypoalbuminemia: Results of a Preliminary Study.

RCTn = 18Heart Health

RCT of 18 in-hospital heart failure patients with hypoalbuminemia comparing oral BCAA supplementation to no supplementation. BCAA group showed increased serum albumin and decreased cardiothoracic ratio, indicating potential benefits for heart health.

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2017·Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme·Mark Waldron, Kieran Whelan, Owen Jeffries, et al

The effects of acute branched-chain amino acid supplementation on recovery from a single bout of hypertrophy exercise in resistance-trained athletes.

RCTn = 16Recovery Physical Performance

This RCT investigated the effects of acute BCAA supplementation on recovery from exercise-induced muscle damage in resistance-trained athletes. BCAA supplementation improved recovery in isometric strength, CMJ height, and perceived muscle soreness compared to placebo after hypertrophy training.

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2017·The British journal of nutrition·Liufeng Zheng, Fangrui Zuo, Shengjun Zhao, et al

Dietary supplementation of branched-chain amino acids increases muscle net amino acid fluxes through elevating their substrate availability and intramuscular catabolism in young pigs.

RCTn = 14Physical Performance

This study investigated the effect of dietary supplementation of branched-chain amino acids (BCAA) on muscle net amino acid fluxes in young pigs. BCAA supplementation increased muscle net fluxes of essential and non-essential amino acids, associated with elevated arterial concentrations and intramuscular catabolism of BCAA.

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2016·Journal of the International Society of Sports Nutrition·Wesley C Kephart, Petey W Mumford, Anna E McCloskey, et al

Post-exercise branched chain amino acid supplementation does not affect recovery markers following three consecutive high intensity resistance training bouts compared to carbohydrate supplementation.

RCTn = 30Recovery -Physical Performance -

RCT comparing branched chain amino acid and carbohydrate supplementation to carbohydrate-only supplementation in 30 resistance-trained males over three days of intense weight training. BCAA-CHO supplementation did not reduce decrements in lower body strength or improve markers of muscle damage/soreness compared to CHO supplementation.

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2016·Modern rheumatology·Noritada Yoshikawa, Noriaki Shimizu, Masaaki Uehara, et al

The effects of bolus supplementation of branched-chain amino acids on skeletal muscle mass, strength, and function in patients with rheumatic disorders during glucocorticoid treatment.

RCTn = 18Physical Performance Joint Bone Health

RCT testing the effects of 12g daily BCAA supplementation on skeletal muscle mass, strength, and function in patients with rheumatic disorders on glucocorticoid treatment. BCAA supplementation improved whole-body muscle mass, muscle strength, and functional mobility compared to control.

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2016·Journal of the International Society of Sports Nutrition·I-Fan Chen, Huey-June Wu, Chung-Yu Chen, et al

Branched-chain amino acids, arginine, citrulline alleviate central fatigue after 3 simulated matches in taekwondo athletes: a randomized controlled trial.

RCTn = 12Physical Performance Mental Clarity

RCT investigating the effect of combined supplementation of BCAA, arginine, and citrulline on central fatigue in 12 male taekwondo athletes. The supplementation maintained cognitive performance and improved reaction times compared to placebo, suggesting alleviation of exercise-induced central fatigue.

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2016·The Journal of sports medicine and physical fitness·Thomas I Gee, Stefan Deniel

Branched-chain aminoacid supplementation attenuates a decrease in power-producing ability following acute strength training.

RCTn = 11Physical Performance Recovery

RCT investigating the effects of BCAA supplementation on recovery of power-producing ability following strength training in 11 resistance-trained males. BCAA attenuated decrements in countermovement jump and seated shot-put throw performance compared to placebo, suggesting it is an effective ergogenic aid for recovery.

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2015·Journal of gastroenterology·Toru Beppu, Hidetoshi Nitta, Hiromitsu Hayashi, et al

Effect of branched-chain amino acid supplementation on functional liver regeneration in patients undergoing portal vein embolization and sequential hepatectomy: a randomized controlled trial.

RCTn = 28

This randomized controlled trial studied the effects of branched chain amino acid (BCAA) supplementation on liver function and regeneration in patients undergoing portal vein embolization and major hepatectomy. The BCAA group showed significant improvements in functional liver regeneration compared to the control group.

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2015·Folia neuropathologica·Tomasz Mikulski, Jan Dabrowski, Wojciech Hilgier, et al

Effects of supplementation with branched chain amino acids and ornithine aspartate on plasma ammonia and central fatigue during exercise in healthy men.

RCTn = 11Physical Performance Recovery

RCT with 11 endurance-trained men testing BCAA + OA supplementation versus placebo during exhaustive exercise. BCAA + OA improved multiple choice reaction time and accelerated ammonia elimination during recovery compared to placebo.

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2014·Amino acids·Francisco Areces, Juan Jose Salinero, Javier Abian-Vicen, et al

A 7-day oral supplementation with branched-chain amino acids was ineffective to prevent muscle damage during a marathon.

RCTn = 46Physical Performance -Recovery -

RCT of 46 experienced runners testing 7-day BCAA supplementation (5 g/day) versus placebo before a marathon. BCAA supplementation did not improve running performance, prevent muscle power loss, muscle damage, or perceived muscle pain during the marathon.

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2012·Journal of nutritional science and vitaminology·Beat Knechtle, Claudia Mrazek, Andrea Wirth, et al

Branched-chain amino acid supplementation during a 100-km ultra-marathon--a randomized controlled trial.

RCTn = 28Physical Performance -Joint Bone Health -

RCT investigating the effect of branched-chain amino acid supplementation on skeletal muscle damage and renal function during a 100-km ultra-marathon. No differences were found in race time, energy intake, antioxidants, or parameters of skeletal muscle damage and renal function between the BCAA and control groups.

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2011·Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme·Piotr Wiśnik, Jan Chmura, Andrzej Wojciech Ziemba, et al

The effect of branched chain amino acids on psychomotor performance during treadmill exercise of changing intensity simulating a soccer game.

RCTn = 10Physical Performance

RCT with 10 male soccer players testing the effect of BCAA ingestion on psychomotor performance during treadmill exercise simulating a soccer game. BCAA supplementation resulted in a ~10% shorter multiple-choice reaction time compared to placebo, suggesting improved psychomotor performance.

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2011·Journal of dairy science·J A D R N Appuhamy, J R Knapp, O Becvar, et al

Effects of jugular-infused lysine, methionine, and branched-chain amino acids on milk protein synthesis in high-producing dairy cows.

RCTn = 9

RCT investigating the effects of jugular-infused lysine, methionine, and branched-chain amino acids (BCAA) on milk protein synthesis in high-producing dairy cows. While methionine and lysine supplementation improved milk protein yield and content compared to control, BCAA supplementation showed no apparent benefits for milk protein synthesis but may have stimulated synthesis of other body proteins.

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2011·American journal of physiology. Endocrinology and metabolism·Marcus Borgenvik, William Apró, Eva Blomstrand

Intake of branched-chain amino acids influences the levels of MAFbx mRNA and MuRF-1 total protein in resting and exercising human muscle.

RCTn = 7Physical Performance

This study examined the effects of resistance exercise and BCAA supplementation on anabolic and catabolic gene expression in human skeletal muscle. BCAA intake reduced MAFbx mRNA and prevented the exercise-induced increase in MuRF-1 total protein in both resting and exercising legs, suggesting a positive influence on muscle protein turnover.

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2011·The Journal of sports medicine and physical fitness·A B Gualano, T Bozza, P Lopes De Campos, et al

Branched-chain amino acids supplementation enhances exercise capacity and lipid oxidation during endurance exercise after muscle glycogen depletion.

RCTn = 7Physical Performance Energy

This study used a double-blind cross-over design to test BCAA supplementation in 7 volunteers undergoing exercise-induced glycogen depletion. BCAA supplementation increased resistance to fatigue by 17.2% and enhanced lipid oxidation during exhaustive exercise compared to placebo.

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2010·International journal of sport nutrition and exercise metabolism·Yoshiharu Shimomura, Asami Inaguma, Satoko Watanabe, et al

Branched-chain amino acid supplementation before squat exercise and delayed-onset muscle soreness.

RCTn = 12Physical Performance Recovery

The study examined the effect of BCAA supplementation on squat-exercise-induced delayed-onset muscle soreness (DOMS) in 12 young, healthy, untrained female participants using a crossover double-blind design. BCAA supplementation significantly reduced DOMS and suppressed the decrease in muscle force compared to placebo. Plasma BCAA concentrations were elevated post-exercise in the BCAA trial, and serum myoglobin concentration increased only in the placebo trial.

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2010·Acta physiologica (Oxford, England)·W Apró, E Blomstrand

Influence of supplementation with branched-chain amino acids in combination with resistance exercise on p70S6 kinase phosphorylation in resting and exercising human skeletal muscle.

RCTn = 9

The study investigated the effects of resistance exercise and BCAA supplementation on p70S6 kinase phosphorylation in human skeletal muscle. BCAA intake increased p70S6k phosphorylation in both resting and exercising muscle, indicating separate and combined effects with resistance exercise on protein synthesis regulation.

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2009·The Journal of sports medicine and physical fitness·K Matsumoto, T Koba, K Hamada, et al

Branched-chain amino acid supplementation attenuates muscle soreness, muscle damage and inflammation during an intensive training program.

RCTn = 12Physical Performance Inflammation Recovery

Double-blinded crossover study with 12 long-distance runners assessing BCAA supplementation during intensive training. BCAA reduced muscle soreness, fatigue sensation, and markers of muscle damage and inflammation compared to placebo.

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2009·Journal of nutritional science and vitaminology·Keitaro Matsumoto, Takashige Koba, Koichiro Hamada, et al

Branched-chain amino acid supplementation increases the lactate threshold during an incremental exercise test in trained individuals.

RCTn = 8Physical Performance

Double-blind crossover placebo-controlled study with 8 trained male subjects investigating the effects of BCAA supplementation on lactate threshold during an incremental exercise test. BCAA supplementation increased plasma BCAA concentration, VO2, and workload levels at lactate threshold, suggesting improved endurance exercise capacity.

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2007·Journal of gastroenterology and hepatology·Ewert Schulte-Frohlinde, Stefan Wagenpfeil, Johanna Willis, et al

Role of meal carbohydrate content for the imbalance of plasma amino acids in patients with liver cirrhosis.

RCTn = 18Nutrition

The study examined the effect of meal carbohydrate content on plasma amino acid concentrations in patients with liver cirrhosis. It found that carbohydrate content enhances the reduction of BCAA plasma concentrations in cirrhotic patients, and a carbohydrate-reduced diet alone does not correct the imbalanced BCAA/AAA ratio, suggesting the need for BCAA supplementation.

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2007·The American journal of clinical nutrition·Mariëlle P K J Engelen, Erica P A Rutten, Carmen L N De Castro, et al

Supplementation of soy protein with branched-chain amino acids alters protein metabolism in healthy elderly and even more in patients with chronic obstructive pulmonary disease.

RCTn = 16Nutrition

RCT examining the effect of BCAA supplementation to soy protein on protein metabolism in 8 COPD patients and 8 healthy elderly. BCAA supplementation enhanced whole-body protein synthesis in COPD patients but not in healthy elderly, and altered interorgan protein metabolism favorably.

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2006·Journal of the American College of Nutrition·Fu-Chun Tang

Influence of branched-chain amino acid supplementation on urinary protein metabolite concentrations after swimming.

RCTn = 19Physical Performance

Double-blind, counter-balanced study on the effect of BCAA supplementation on urinary protein metabolite concentrations after swimming in male university students. BCAA supplementation prevented the increase in urinary urea nitrogen, hydroxyproline, and 3-methylhistidine concentrations observed in the placebo group, suggesting reduced muscle proteolysis.

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2005·Nutrition (Burbank, Los Angeles County, Calif.)·Shinji Togo, Kuniya Tanaka, Daisuke Morioka, et al

Usefulness of granular BCAA after hepatectomy for liver cancer complicated with liver cirrhosis.

RCTn = 43Nutrition

RCT examining the effect of BCAA granules on nutritional status after hepatectomy in liver cancer patients with cirrhosis. The BCAA group showed faster recovery of serum albumin and improvements in protein metabolism compared to the control group.

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2004·European journal of applied physiology·Phillip Watson, Susan M Shirreffs, Ronald J Maughan

The effect of acute branched-chain amino acid supplementation on prolonged exercise capacity in a warm environment.

RCTn = 8Physical Performance -

RCT with 8 males examining the effect of BCAA supplementation on exercise capacity in a glycogen-depleted state in a warm environment. BCAA ingestion did not influence exercise capacity, heart rate, core temperature, or blood glucose and lactate concentrations compared to placebo.

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2004·Journal of applied physiology (Bethesda, Md. : 1985)·Samuel N Cheuvront, Robert Carter, Margaret A Kolka, et al

Branched-chain amino acid supplementation and human performance when hypohydrated in the heat.

RCTn = 7Physical Performance -Mental Clarity -

RCT with 7 heat-acclimated men testing BCAA supplementation on exercise and cognitive performance in the heat when hypohydrated. BCAA increased plasma levels but did not alter exercise or cognitive performance, mood, perceived exertion, or thermal comfort.

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2003·Diabetes, nutrition & metabolism·A De Lorenzo, M L Petroni, S Masala, et al

Effect of acute and chronic branched-chain amino acids on energy metabolism and muscle performance.

RCTn = 12Energy Physical Performance

The study investigated the effects of acute and chronic BCAA administration on energy metabolism and muscle performance in healthy male volunteers. Acute BCAA administration increased respiratory quotient for a longer duration compared to placebo, while chronic BCAA supplementation improved grip strength without significant changes in arm muscle area.

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2001·Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association·K Hiroshige, T Sonta, T Suda, et al

Oral supplementation of branched-chain amino acid improves nutritional status in elderly patients on chronic haemodialysis.

RCTn = 28Nutrition

A 12-month, placebo-controlled, double-blind study on 28 malnourished elderly haemodialysis patients with anorexia. Oral BCAA supplementation improved anorexia, increased plasma BCAA levels, and improved nutritional status, including increased plasma albumin concentration and anthropometric indices.

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2000·Medicine and science in sports and exercise·R A Bassit, L A Sawada, R F Bacurau, et al

The effect of BCAA supplementation upon the immune response of triathletes.

RCTn = 12Immunity

RCT involving 12 elite male triathletes assessing the effect of BCAA supplementation on immune response. BCAA supplementation prevented the reduction in plasma glutamine concentration and improved lymphocyte response and cytokine production, potentially reducing symptoms of infection.

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1996·The Journal of physiology·D A MacLean, T E Graham, B Saltin

Stimulation of muscle ammonia production during exercise following branched-chain amino acid supplementation in humans.

RCTPhysical Performance

This study examined the effects of a large oral dose of branched-chain amino acids (BCAAs) on muscle amino acid and ammonia metabolism during 90 minutes of dynamic knee extensor exercise. BCAA supplementation increased arterial and intramuscular BCAA levels, enhanced muscle ammonia, alanine, and glutamine production, and reduced lactate production compared to control.

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1994·Nutrition (Burbank, Los Angeles County, Calif.)·P Hassmén, E Blomstrand, B Ekblom, et al

Branched-chain amino acid supplementation during 30-km competitive run: mood and cognitive performance.

RCTMental Clarity Mood -

RCT examining the effects of BCAA supplementation during a 30-km race on mood and cognitive performance. BCAA supplementation improved performance in complex cognitive tasks post-exercise, but had only slight effects on exercise-induced mood changes.

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1998·Medicine and science in sports and exercise·K D Mittleman, M R Ricci, S P Bailey

Branched-chain amino acids prolong exercise during heat stress in men and women.

RCTn = 13Physical Performance

RCT assessing the effect of BCAA supplementation on endurance performance in the heat with 6 women and 7 men. BCAA supplementation increased cycle time to exhaustion compared to placebo, indicating improved exercise performance in the heat.

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1998·Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme·H K Strüder, W Hollmann, P Platen, et al

Influence of paroxetine, branched-chain amino acids and tyrosine on neuroendocrine system responses and fatigue in humans.

RCTn = 10Physical Performance -Mental Clarity

RCT with 10 male subjects cycling until exhaustion under four conditions: placebo, paroxetine, BCAA, and tyrosine. BCAA and tyrosine supplementation did not significantly affect physical fatigue, but improved drive during psychometric testing. Plasma ammonia increased with BCAA, and plasma prolactin increments were higher with tyrosine.

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1997·Diabetes care·A Mourier, J F Gautier, E De Kerviler, et al

Mobilization of visceral adipose tissue related to the improvement in insulin sensitivity in response to physical training in NIDDM. Effects of branched-chain amino acid supplements.

RCTn = 24Nutrition -

RCT evaluating the effects of physical training and BCAA supplementation on abdominal fat distribution, glycemic control, and insulin sensitivity in patients with NIDDM. Physical training improved insulin sensitivity and reduced visceral adipose tissue, but BCAA supplementation had no effect on abdominal fat and glucose metabolism.

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1997·The American journal of physiology·M L Jackman, M J Gibala, E Hultman, et al

Nutritional status affects branched-chain oxoacid dehydrogenase activity during exercise in humans.

RCTn = 6

The study examined the effect of glycogen availability and BCAA supplementation on BCOAD activity during exercise in six subjects. BCOAD activity was higher during exercise under low glycogen conditions with and without BCAA supplementation compared to high glycogen conditions, indicating rapid activation during submaximal exercise with low carbohydrate availability.

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1996·Archives of physiology and biochemistry·D Freyssenet, P Berthon, C Denis, et al

Effect of a 6-week endurance training programme and branched-chain amino acid supplementation on histomorphometric characteristics of aged human muscle.

RCTn = 17

The study investigated the effects of a 6-week endurance training program and BCAA supplementation on skeletal muscle histomorphometric characteristics in elderly men. Both the BCAA supplemented group and the placebo group showed increased maximal oxygen uptake and capillarization, but BCAA supplementation did not further enhance these changes.

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1992·Hepato-gastroenterology·G P Bianchi, G Marchesini, M Zoli, et al

Oral BCAA supplementation in cirrhosis with chronic encephalopathy: effects on prolactin and estradiol levels.

RCTn = 49Hormone Health -Mental Clarity Nutrition

Retrospective analysis of a 3-month RCT on oral BCAA supplementation in patients with cirrhosis and chronic hepatic encephalopathy. BCAA supplementation did not change fasting prolactin or estradiol levels but improved mental state and supported liver function and nutritional parameters compared to casein.

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1992·European journal of applied physiology and occupational physiology·F Schena, F Guerrini, P Tregnaghi, et al

Branched-chain amino acid supplementation during trekking at high altitude. The effects on loss of body mass, body composition, and muscle power.

RCTn = 16Physique Physical Performance

RCT of 16 subjects trekking at high altitude, comparing BCAA supplementation to placebo. BCAA group showed increased lean mass and less muscle power decrease compared to placebo, suggesting BCAA may prevent muscle loss during chronic hypobaric hypoxia.

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2014·Liver international : official journal of the International Association for the Study of the Liver·Masaaki Korenaga, Sohji Nishina, Keiko Korenaga, et al

Branched-chain amino acids reduce hepatic iron accumulation and oxidative stress in hepatitis C virus polyprotein-expressing mice.

Animal studyInflammation

The study investigated the effects of branched-chain amino acids (BCAA) on hepatic iron accumulation and oxidative stress in hepatitis C virus polyprotein-expressing mice and patients with HCV-related advanced fibrosis. BCAA supplementation increased serum hepcidin-25 levels, improved antioxidant status, decreased hepatic iron content, and restored mitochondrial function in mice. In patients, BCAA increased BAP/dROM and serum hepcidin-25 while decreasing serum ferritin.

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