Research
Glycerol (Hyperhydration)
16 peer-reviewed studies curated from PubMed and Semantic Scholar.
Studies
Sorted by quality and recency
The efficacy of glycerin suppositories for preterm infants: A meta-analysis of randomized controlled studies.
Meta-analysis of six randomized controlled trials assessing the effect of glycerin suppositories on full enteral feeds in preterm infants. Glycerin suppositories demonstrated no significant effect on days to full enteral feeds, incidence of necrotizing enterocolitis, or death, but may increase days under phototherapy.
Clinical benefit and tolerance profile of a keratolytic and hydrating shampoo in subjects with mild to moderate psoriasis. Results from a double-blind, randomized, vehicle-controlled study.
A double-blind, randomized, vehicle-controlled study assessed the efficacy and tolerability of a shampoo containing 2% salicylic acid, 5% urea, and 1% glycerin in 67 adults with mild to moderate scalp psoriasis. The active shampoo significantly reduced the Psoriasis Scalp Severity Index and improved quality of life compared to the vehicle, with high subject satisfaction and good tolerance.
Meta-analysis: Effects of glycerol administration on plasma volume, haemoglobin, and haematocrit.
Meta-analysis of seven studies examining the effects of glycerol hyperhydration on plasma volume, haemoglobin, and haematocrit compared to fluid only. Glycerol administration increased plasma volume by 3.3% more than fluid alone, with a slight reduction in haemoglobin and no significant difference in haematocrit.
Combined glycerol and sodium bicarbonate elicits improvements in fluid retention and blood buffering capacity.
This study evaluated the effects of glycerol, sodium bicarbonate, and their combination on fluid retention, blood buffering capacity, and gastrointestinal symptoms in 11 healthy participants. Fluid retention improved with all treatments compared to control, but no additive effects were observed with the combination. Blood pH and bicarbonate concentration were higher with sodium bicarbonate and the combination compared to glycerol and control.
A randomized trial modeling the effects of solutions with low to moderate glycerol and sodium concentrations on fluid balance in healthy, active adults.
A randomized trial evaluated the impact of low to moderate concentrations of glycerol and sodium on fluid balance in 37 healthy, active adults. The study found that glycerol alone or in combination with sodium promoted better fluid balance compared to placebo.
The Addition of Glycerol and Sodium Chloride to a Hyperhydration Protocol Does Not Improve Half-Marathon Time-Trial Performance in Trained Runners in Warm Conditions.
RCT examining the effect of glycerol- and sodium-induced hyperhydration on half-marathon performance in warm conditions. Hyperhydration increased fluid retention and plasma volume but did not improve exercise performance or affect gastrointestinal symptoms, temperature, or heart rate.
Hyperhydration with Glycerol, Sodium, and Isomaltulose or Sucrose on Fluid Balance, Thermoregulation, and Exercise Capacity in the Heat.
RCT with 13 healthy men testing beverages containing glycerol, sodium, and either sucrose or isomaltulose on fluid balance, thermoregulation, and exercise capacity in heat. Glycerol and sodium reduced urine volume, and isomaltulose further enhanced this effect. Plasma volume increased with sucrose and isomaltulose, but no differences in exercise performance were found.
Effects of ingesting beverages containing glycerol and sodium with isomaltulose or sucrose on fluid retention in young adults: a single-blind, randomized crossover trial.
A single-blind, randomized crossover trial with 14 young adults evaluated the effects of beverages containing glycerol and sodium with either isomaltulose or sucrose on fluid retention. Beverages with glycerol and sodium reduced total urine volume compared to water. Isomaltulose increased the beverage hydration index significantly, while sucrose did not.
Effects of pre-exercise glycerol supplementation on dehydration, metabolic, kinematic, and thermographic variables in international race walkers.
RCT with 8 international male race walkers evaluating pre-exercise glycerol supplementation on dehydration, metabolic, kinematic, and thermographic variables. No significant improvements were found in these variables compared to placebo.
High amplitude propagated contractions with Glycerin versus Bisacodyl: A within-subject comparison in children undergoing colonic manometry.
Prospective cross-over study comparing the effects of Bisacodyl and Glycerin on high amplitude propagated contractions (HAPCs) in children undergoing colonic manometry for constipation. Bisacodyl resulted in longer duration, longer propagation, and more HAPCs compared to Glycerin, with no differences in amplitude and onset of action.
Novel formulation of glycerin 1% artificial tears extends tear film break-up time compared with Systane lubricant eye drops.
This randomized, double-masked exploratory trial compared a novel glycerin 1% formulation with Systane lubricant eye drops in extending tear film break-up time (TFBUT). The new formulation significantly prolonged noninvasive break-up time (NIBUT) at 15 minutes and showed a longer fluorescein break-up time (FBUT) at 120 minutes compared to Systane.
Glycerol hyperhydration: physiological responses during cold-air exposure.
This study examined the physiological responses to glycerol ingestion in seven men during 4 hours of cold-air exposure. Glycerol ingestion resulted in greater fluid retention compared to water alone, indicating it can be an effective hyperhydrating agent during cold-air exposure.
Glycerol hyperhydration fails to improve endurance performance and thermoregulation in humans in a warm humid environment.
RCT comparing glycerol hyperhydration to water hyperhydration in seven trained subjects during a 60-minute variable-intensity cycling protocol in hot, humid conditions. Glycerol hyperhydration showed no significant advantage over water in terms of endurance performance or thermoregulation.
The effect of glycerol hyperhydration on olympic distance triathlon performance in high ambient temperatures.
This study examined the effect of glycerol loading on Olympic distance triathlon performance in high ambient temperatures. Ten well-trained triathletes completed two triathlons under placebo and glycerol conditions. Glycerol loading resulted in less performance decrement in the heat, particularly during the final run leg, due to increased fluid retention and plasma volume expansion.
Plasma volume changes during and after acute variations of body hydration level in humans.
This study examined plasma volume changes in humans during exercise-induced dehydration, heat-induced dehydration, and glycerol hyperhydration. Eight well-trained men completed four trials in randomized order. Glycerol ingestion induced an increase in plasma volume, while plasma volume declined during heat-induced and exercise-induced dehydration.
Hyperhydration: thermoregulatory effects during compensable exercise-heat stress.
This study examined the effects of hyperhydration, with or without glycerol, on thermoregulatory responses during exercise-heat stress. Eight heat-acclimated men completed trials comparing euhydration, glycerol hyperhydration, and water hyperhydration. Hyperhydration did not alter core temperature, skin temperature, sweating rates, or heart rate responses compared to euhydration.