Research

L-Cysteine

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

3
Meta-analyses
0
Systematic reviews
10
RCTs
0
Other studies
Meta-analyses (23%)
RCTs (77%)

Studies

Sorted by quality and recency

2026·In vivo (Athens, Greece)·Kari Syrjänen, Osmo Suovaniemi

Slow-release L-cysteine Lozenges in Smoking Cessation: Meta-analysis of Two Randomized Controlled Trials.

Meta-analysisn = 2,421

Meta-analysis of two RCTs testing slow-release L-cysteine lozenges (Acetium) for smoking cessation. The analysis showed that Acetium significantly increased the likelihood of successful smoking cessation compared to placebo, with a 1.5-fold increase in success rates.

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2024·Aging cell·Yue Ma, Mengqi Chen, Kaiyao Huang, et al

The impact of cysteine on lifespan in three model organisms: A systematic review and meta-analysis.

Meta-analysisLongevity

Systematic review and meta-analysis of cysteine supplementation on lifespan in mice, nematodes, and fruit flies. Cysteine reduced mortality risk in mice and C. elegans, but effects were not significant in Drosophila except in transgenic flies. High doses had adverse effects on worms, and no effect was observed in nondisease mouse models.

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2016·Anticancer research·Kari Syrjänen, Johanna Salminen, Ulla Aresvuo, et al

Elimination of Cigarette Smoke-derived Acetaldehyde in Saliva by Slow-release L-Cysteine Lozenge Is a Potential New Method to Assist Smoking Cessation. A Randomised, Double-blind, Placebo-controlled Intervention.

RCTn = 423

A double-blind, randomized, placebo-controlled trial tested the efficacy of slow-release L-cysteine lozenges in reducing acetaldehyde in saliva to assist smoking cessation. Among 423 smokers, 65 participants quit smoking during the 6-month trial, with a higher quit rate in the intervention group compared to placebo, though results were not statistically significant.

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2006·The Cochrane database of systematic reviews·L M Soghier, L P Brion

Cysteine, cystine or N-acetylcysteine supplementation in parenterally fed neonates.

Meta-analysisn = 95

Meta-analysis of RCTs evaluating cysteine, cystine, or N-acetylcysteine supplementation in parenterally fed neonates. Cysteine supplementation improved nitrogen retention but did not significantly affect growth. N-acetylcysteine supplementation did not significantly affect mortality or morbidity outcomes.

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2020·Alcohol and alcoholism (Oxford, Oxfordshire)·C J Peter Eriksson, Markus Metsälä, Tommi Möykkynen, et al

L-Cysteine Containing Vitamin Supplement Which Prevents or Alleviates Alcohol-related Hangover Symptoms: Nausea, Headache, Stress and Anxiety.

RCTn = 19Stress Mood

Randomized, double-blind, placebo-controlled trial with 19 male participants to investigate the effect of L-cysteine on alcohol-related hangover symptoms. L-cysteine was found to prevent or alleviate hangover, nausea, headache, stress, and anxiety, with significant effects at doses of 600mg and 1200mg.

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2014·Indian journal of ophthalmology·Alessandro Meduri, Lucia Scorolli, Sergio Zaccaria Scalinci, et al

Effect of the combination of basic fibroblast growth factor and cysteine on corneal epithelial healing after photorefractive keratectomy in patients affected by myopia.

RCTn = 120

RCT evaluating the effect of basic fibroblast growth factor eye drops and oral L-cysteine supplements on corneal healing in 120 patients post-PRK for myopia. Group 1, receiving both treatments, showed faster corneal re-epithelialization by Day 5 compared to Day 6 in the control group receiving only eye drops.

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2008·Ophthalmic research·Alessandro Meduri, Pier Luigi Grenga, Lucia Scorolli, et al

Role of cysteine in corneal wound healing after photorefractive keratectomy.

RCTn = 100

RCT evaluating the efficacy of oral cysteine supplements in corneal wound healing after photorefractive keratectomy (PRK). Patients treated with cysteine showed shorter times to re-epithelization compared to the control group, with a mean healing time of 102 hours versus 159 hours.

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2019·Climacteric : the journal of the International Menopause Society·Y Li, X Ruan, J Liebenthron, et al

Ovarian tissue cryopreservation for patients with premature ovary insufficiency caused by cancer treatment: optimal protocol.

RCTn = 13Womens Health

The study investigated the protective effect of acetyl-l-cysteine (NAC) during ovarian tissue cryopreservation and thawing in cancer patients. Different NAC concentrations were tested, with 5 mM NAC showing the highest antioxidant capacity and lowest ROS levels, but mixed results on follicle viability and apoptotic parameters.

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2016·Scandinavian journal of gastroenterology·Per M Hellström, Panu Hendolin, Pertti Kaihovaara, et al

Slow-release L-cysteine capsule prevents gastric mucosa exposure to carcinogenic acetaldehyde: results of a randomised single-blinded, cross-over study of Helicobacter-associated atrophic gastritis.

RCTn = 7

A randomised single-blinded cross-over study in seven patients with atrophic gastritis assessed the effect of slow-release L-cysteine on gastric acetaldehyde levels after alcohol intake. L-cysteine administration increased MTCA and decreased gastric acetaldehyde concentrations by 68%, suggesting it mitigates local exposure of the gastric mucosa to carcinogenic acetaldehyde.

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2010·Alcoholism, clinical and experimental research·Klas Linderborg, Tuuli Marvola, Martti Marvola, et al

Reducing carcinogenic acetaldehyde exposure in the achlorhydric stomach with cysteine.

RCTn = 7

Double-blinded randomized trial with 7 volunteers with achlorhydric atrophic gastritis to test L-cysteine's ability to bind acetaldehyde in the stomach after ethanol ingestion. L-cysteine significantly reduced acetaldehyde levels in gastric juice compared to placebo.

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2002·Photodermatology, photoimmunology & photomedicine·Micheline M Mathews-Roth, Bernard Rosner

Long-term treatment of erythropoietic protoporphyria with cysteine.

RCTn = 47

A Phase III 3-year placebo-controlled trial with 47 patients assessed the efficacy of L-cysteine-HCl in preventing or ameliorating photosensitivity in erythropoietic protoporphyria. Cysteine increased the time of symptom-free light exposure to a statistically significant degree.

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2002·International journal of cancer·Ville Salaspuro, Jaana Hietala, Pertti Kaihovaara, et al

Removal of acetaldehyde from saliva by a slow-release buccal tablet of L-cysteine.

RCTn = 9

RCT with 9 healthy male volunteers testing a slow-release buccal tablet of L-cysteine to bind carcinogenic acetaldehyde in saliva after ethanol ingestion. The L-cysteine tablet reduced salivary acetaldehyde concentration by 59% compared to placebo, suggesting potential use in preventing upper GI-tract cancers.

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1985·Pharmatherapeutica·S G Harvey, J R Gibson, C A Burke

L-cysteine, glycine and dl-threonine in the treatment of hypostatic leg ulceration: a placebo-controlled study.

RCTn = 21Skin Hair Health

A randomized, double-blind, placebo-controlled trial in 22 patients with hypostatic leg ulceration treated topically with a cream containing l-cysteine, glycine, and dl-threonine. The amino acid combination significantly improved healing and decreased pain compared to placebo.

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