Glycerol
Glycerol (Glycerin)
A hyperhydrating compound that helps the body retain water, improving endurance performance and thermoregulation in heat.
Glycerol is a naturally occurring compound that attracts and retains water in the body. When consumed before exercise, it creates a state of hyperhydration, allowing athletes to carry extra fluid into competition. This is particularly beneficial for endurance events in hot conditions, where dehydration and overheating limit performance. Glycerol has been shown to improve endurance, delay fatigue, and enhance thermoregulation.
Mechanisms of Action
Hyperhydration
Increases total body water above normal levels
Improved Thermoregulation
Better heat dissipation during exercise
Increased Plasma Volume
More blood volume for cardiovascular function
Recommended Dose
1-1.5g per kg body weight
Loading: Take 1-2.5 hours before exercise with 25-30ml water per gram of glycerol
Optimal Timing
- 1-2.5 hours before endurance exercise
- Consume with large volume of fluid (1-2L)
Can be taken without food
Best Form
Glycerol powder (65% concentration typical)
Alternatives: GlycerSize (65% glycerol powder), Liquid glycerol
Pure glycerol is very viscous. Powder forms (65-85% glycerol) are easier to mix. Practice protocol before competition.
Duration
Minimum: 1 days
Optimal: 1 days
Cycling: Use only for key competitions or hot-weather training; not for daily use
Note: Must be consumed with adequate water (25-30ml per gram glycerol). Allow time for absorption before exercise begins.
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Extended Endurance
Longer time to exhaustion in endurance events
Better Heat Performance
Improved performance in hot conditions
Lower Heart Rate
Reduced cardiovascular strain during exercise
GI Discomfort
Bloating, nausea, or headache in some users
Not recommended; unnecessary
Primary target population; practice before competition
Who Should NOT Take This
- Kidney disease
- Diabetes (may affect blood sugar)
- Heart failure (fluid retention)
Drug Interactions
Opposing effects on fluid balance — may affect electrolyte balance or enhance fluid loss — may affect electrolyte balance or enhance fluid loss
May affect blood sugar; monitor levels
Possible Side Effects
Tip: Expected; should resolve as exercise begins
Tip: Ensure adequate electrolytes
Tip: Reduce dose; practice protocol in training
Tip: Practice in training; adjust dose
Warnings
- Always practice protocol in training before competition
- Must consume with large volume of water
- May cause initial bloating sensation
Top studies from 40+ peer-reviewed papers
Wall EC et al. • The Cochrane database of systematic reviews (2018)
“Glycerol was the only osmotic therapy evaluated, and data from trials to date have not demonstrated an effect on death.”
Key Findings:
- Four trials evaluated glycerol against placebo, and one evaluated glycerol against 50% dextrose; in addition three trials evaluated dexamethasone and one trial evaluated acetaminophen (paracetamol) in a factorial design.
- The evidence on nausea, vomiting and diarrhoea is uncertain (RR 1.09, 95% CI 0.81 to 1.47; 2 studies, 851 participants; very low-certainty evidence).
- Glycerol was the only osmotic therapy evaluated, and data from trials to date have not demonstrated an effect on death.
- Glycerol may reduce neurological deficiency and deafness.
van Zuuren EJ et al. • The Cochrane database of systematic reviews (2017)
“Most moisturisers showed some beneficial effects, producing better results when used with active treatment, prolonging time to flare, and reducing the number of flares and amount of topical corticosteroids needed to achieve similar reductions in eczema severity.”
Key Findings:
- Moisturiser use yielded lower SCORAD than no moisturiser (three studies, 276 participants, mean difference (MD) -2.42, 95% confidence interval (CI) -4.55 to -0.28), but the minimal important difference (MID) (8.7) was unmet.
- There were fewer flares with moisturisers (two studies, 87 participants, RR 0.40, 95% CI 0.23 to 0.70), time to flare was prolonged (median: 180 versus 30 days), and less topical corticosteroids were needed (two studies, 222 participants, MD -9.30 g, 95% CI -15.3 to -3.27).
- There was no statistically significant difference in adverse events (one study, 173 participants, risk ratio (RR) 15.34, 95% CI 0.90 to 261.64).
- Evidence for these outcomes was low quality.With Atopiclair (three studies), 174/232 participants experienced improvement in participant-assessed disease severity versus 27/158 allocated to vehicle (RR 4.51, 95% CI 2.19 to 9.29).
SohrabiAsl M et al. • Stereotactic and functional neurosurgery (2024)
“This meta-analysis provides a comprehensive overview of less-invasive treatments for TGN in MS patients.”
Key Findings:
- GKRS demonstrated favorable outcomes, achieving a 77% success rate in alleviating pain among a pooled cohort of 863 patients, reinforcing its status as a viable therapeutic option.
- Additionally, GR, BC, and RFA exhibited efficacy, with success rates of 77%, 71%, and 80%, respectively, based on outcomes observed in 611, 385, and 203 patients.
- This meta-analysis provides a comprehensive overview of less-invasive treatments for TGN in MS patients.
- GKRS emerges as a leading option with comparable efficacy and fewer complications.
Vicente-Salar N et al. • Nutrients (2022)
“Caffeine is the only NEA that has shown strong evidence for performance enhancement in combat sports.”
Key Findings:
- In this regard, abilities including the number of attacks, reaction time, handgrip strength, power and TTE, among others, were improved.
- Buffering supplements such as sodium bicarbonate, sodium citrate and beta-alanine may have a promising role in high and intermittent exertion during combat, but more studies are needed in grappling combat sports to confirm their efficacy during sustained isometric exertion.
- Other NEAs, including creatine, beetroot juice or glycerol, need further investigation to strengthen the evidence for performance enhancement in combat sports.
- Caffeine is the only NEA that has shown strong evidence for performance enhancement in combat sports.
Yan C et al. • Acta neurologica Belgica (2022)
“Belgian Neurological Society.”
Key Findings:
- The odds ratio (OR) with 95% confidence interval (CI) was applied to assess effect estimates using the random-effects model.
- We noted that RF was associated with an increased incidence of immediate pain relief compared with GR (OR 2.65; 95% CI 1.29-5.44; P = 0.008).
- Moreover, RF was associated with an increased risk of pain recurrence compared with MVD (OR 3.80; 95% CI 2.00-7.20; P < 0.001).
- Furthermore, RF was associated with an increased incidence of postoperative anesthesia compared with GR (OR 3.01; 95% CI 1.11-8.13; P = 0.030) or MVD (OR 4.62; 95% CI 2.15-9.93; P < 0.001).
Study Type Distribution
Goals This Supplement Supports
This information is for educational purposes only and is not intended as medical advice. Always consult a qualified healthcare provider before starting any supplement.