Glycerol

Osmotic agent that enhances fluid retention, promotes hyperhydration, and improves exercise performance in hot conditions

Scientific name1,2,3-Propanetriol FormulaC3H8O3 Molecular weight92.09 g/mol CAS56-81-5

95 absorption score

7 safety / 10

25 USD per month

5 documented interactions

Check it against something

Evidence level C

Glycerol with:

66 out of 100

Needs attention Separate by 2-4 hours to avoid the interaction below.

Check it against your whole stack →

What it does

mechanism and evidence for each claim

Enhanced fluid retention and hyperhydration

Increases total body water content and fluid retention

Osmotic properties draw and retain water in intracellular compartments Evidence A-grade 60-120 minutes for hyperhydration effects

Improved exercise performance in heat

Enhances exercise capacity and reduces heat stress during hot conditions

Increased plasma volume and improved thermoregulation Evidence B-grade During exercise in hot/humid conditions

Enhanced endurance and reduced fatigue

May improve endurance capacity and delay fatigue onset

Maintained blood volume and cardiovascular function Evidence B-grade During prolonged exercise sessions

Improved thermoregulation and cooling

Enhances body's ability to regulate temperature during exercise

Increased plasma volume supports sweating and heat dissipation Evidence B-grade During heat exposure and exercise

Reduced dehydration and heat illness risk

May help prevent dehydration and heat-related performance decline

Pre-loading with fluids before exercise in challenging conditions Evidence C-grade Pre-exercise loading protocol

Others take these for the same thing

Same goal, different mechanism — check any of them against this one

Creatine Monohydrate Strength & power enhancement 3-5g A 95% Calcium Bone health & muscle function 1,000-1,200 mg A 30% Magnesium Glycinate Superior absorption sleep & muscle support 200-600 mg A 90% Whey Protein Muscle growth & recovery 25-75g A 95% Creatine HCL Enhanced muscle building 1.5-3g B 98% Oregano Oil Powerful respiratory antimicrobial 100-300mg B 85%

Every pair we checked

12 combinations scored by the engine

Glycerol + Caffeine High caffeine doses may have mild diuretic effects Needs attention 66

Glycerol + Creatine Monohydrate No documented interaction either way No known interaction 70

Glycerol + Vitamin D3 No documented interaction either way No known interaction 70

Glycerol + Calcium Carbonate No documented interaction either way No known interaction 70

Glycerol + Whey Protein No documented interaction either way No known interaction 70

Glycerol + Lactase No documented interaction either way No known interaction 70

Glycerol + Bovine Collagen No documented interaction either way No known interaction 70

Glycerol + DHA No documented interaction either way No known interaction 70

Glycerol + Turmeric No documented interaction either way No known interaction 70

Glycerol + Fish Oil (EPA/DHA) No documented interaction either way No known interaction 70

Glycerol + Magnesium Oxide No documented interaction either way No known interaction 70

Glycerol + Marine Collagen No documented interaction either way No known interaction 70

Dosage

2 3 hours pre exercise with fluids

Daily1-1.5g/kg body weight

Hyperhydration protocol1-1.5g/kg body weight with 20-25ml/kg fluid 2-3 hours pre-exercise

Maintenance hydration0.5-1g/kg body weight with adequate fluids

Heat performance1.2-1.5g/kg body weight with electrolytes before hot weather exercise

Endurance preloading1-1.2g/kg body weight with 20ml/kg fluid pre-competition

When to expect it

First Effects60-120 minutes for fluid retention and hyperhydration

Peak Benefits2-4 hours for maximum plasma volume expansion

Deficiency DevelopmentNot applicable - not essential nutrient

Toxicity OnsetGI distress with excessive doses, otherwise very safe

How to measure it

$200-300

MarkerPlasma volume, osmolality, electrolyte balance

Optimal4-7% increase in plasma volume post-loading

Deficient belowNot applicable - ergogenic aid assessment

FrequencyMonitor during hyperhydration protocols if using systematically

What people actually reported to the FDA

CAERS, 0 reports naming it as the suspect

Named as the suspect 0 reports of 1 that mention it at all

Reports are voluntary and unverified — they record what someone experienced while taking something, not what the compound caused. Counts skew towards products people take a lot of, and a serious outcome is more likely to be reported than a mild one, so these are not rates. How we filter them →

What actually reaches you

The label counts the carrier, your body does not

Absorption Very high 95 of 100 · best absorbed form of this compound

Delivered daily 1187.5 mg

Cost per 100 mg delivered $0.07 comparative — uses the absorption score, not a measured percentage

Works better with

3 documented

Electrolytes Sodium Potassium

Enhanced hydration and prevents electrolyte dilution

Maintains electrolyte balance during hyperhydration · level A

Carbohydrates

Enhanced fluid absorption and energy availability

Glucose enhances sodium and water absorption · level B

Caffeine

May enhance performance benefits in combination

Complementary performance enhancement · level C

What not to take with Glycerol

2 documented

Alcohol

Alcohol counteracts fluid retention and hydration benefits

Diuretic effects oppose glycerol's fluid retention · high significance

Excessive Caffeine

High caffeine doses may have mild diuretic effects

May partially oppose fluid retention benefits · minor significance

Medication interactions

Discuss these with a pharmacist before combining

diuretic-medications Moderate

May counteract the effects of diuretic medications

What to do: Avoid concurrent use or adjust medications

blood-pressure-medications Minor

Increased plasma volume may affect blood pressure

What to do: Monitor blood pressure with concurrent use

Available forms

bioavailability compared

Pure Glycerol/Glycerin 95

Pure Glycerol/Glycerin: Effective hyperhydration, Heat performance, Well researched, Cost effective

Food sources

before you supplement

Naturally occurring in fats Small amounts in all dietary fats · 80

Food additive applications Present in many processed foods · 85

Pure glycerol supplements 70-100g doses for hyperhydration · 95

Too little

deficiency signs

Not applicable (not essential nutrient, used as ergogenic aid):
Conditions addressed by glycerol hyperhydration:
Poor heat tolerance and performance decline
Rapid dehydration during exercise
Poor fluid retention and hydration status
Heat exhaustion and thermal stress
Reduced endurance in challenging conditions

Too much

toxicity signs

Generally safe but can cause GI distress:
Gastrointestinal upset with high doses:
Nausea and vomiting
Bloating and abdominal discomfort
Diarrhea and digestive issues
Headache with excessive fluid retention
Risk of hyponatremia with excessive fluid intake

Who benefits most

hot-weather-athletes

Enhanced heat tolerance and performance in challenging conditions

1-1.5g/kg body weight with 20-25ml/kg fluid 2-3 hours pre-exercise

endurance-athletes

Improved fluid status and endurance during long events

1-1.2g/kg body weight with adequate fluids pre-competition

dehydration-prone-athletes

Enhanced fluid retention for those who struggle with hydration

1g/kg body weight with 20ml/kg fluid before training

military-tactical-athletes

Enhanced performance under heat stress and challenging conditions

1-1.5g/kg body weight with fluids before operations

ultra-endurance-competitors

Maximum hydration status for extreme duration events

1-1.2g/kg body weight with electrolytes pre-event

Where to buy it

compare forms first

Look for Glycerol at 1-1.5g/kg body weight per serving. The form that matters here is Pure Glycerol/Glycerin.

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What else affects it

Beyond other supplements

Electrolytes sodium potassium

Enhanced hydration and prevents electrolyte dilution

Maintains electrolyte balance during hyperhydration

Carbohydrates

Enhanced fluid absorption and energy availability

Glucose enhances sodium and water absorption

Alcohol

Alcohol counteracts fluid retention and hydration benefits

Diuretic effects oppose glycerol's fluid retention

Excessive caffeine

High caffeine doses may have mild diuretic effects

May partially oppose fluid retention benefits

How it works

Osmotic agent that draws and retains water in body compartments
Increases plasma volume and total body water content
Enhances cardiovascular function through increased blood volume
Improves thermoregulation by supporting sweating and heat dissipation
Maintains fluid balance during prolonged exercise
Prevents rapid fluid loss through enhanced retention

Key findings

what the evidence supports

Effective for hyperhydration and heat performance enhancement
Most beneficial in hot, humid environmental conditions
Requires proper dosing and timing for optimal effects
Can cause significant GI distress in sensitive individuals

Sources: NIH Examine.com · data reviewed 2026-08-02

Compiled by Denis, who maintains this database and holds no medical qualification — every figure here is sourced or derived, never asserted. How we calculate it →

Common questions

What are the benefits of Glycerol?

Documented effects: Enhanced fluid retention and hyperhydration; Improved exercise performance in heat; Enhanced endurance and reduced fatigue; Improved thermoregulation and cooling. Increases total body water content and fluid retention

How much Glycerol should you take per day?

The common daily range is 1-1.5g/kg body weight. By goal — hyperhydration protocol: 1-1.5g/kg body weight with 20-25ml/kg fluid 2-3 hours pre-exercise; maintenance hydration: 0.5-1g/kg body weight with adequate fluids; heat performance: 1.2-1.5g/kg body weight with electrolytes before hot weather exercise; endurance preloading: 1-1.2g/kg body weight with 20ml/kg fluid pre-competition.

When is the best time to take Glycerol?

2 3 hours pre exercise with fluids. First effects are typically reported within 60-120 minutes for fluid retention and hyperhydration.

What are the side effects of Glycerol?

At excessive doses: Generally safe but can cause GI distress:, Gastrointestinal upset with high doses:, Nausea and vomiting, Bloating and abdominal discomfort, Diarrhea and digestive issues. Safety rating at normal doses is 7 out of 10.

What should you not take with Glycerol?

Separate it from Alcohol, Excessive Caffeine by two to four hours. Alcohol counteracts fluid retention and hydration benefits

Does Glycerol interact with medications?

Documented interactions with diuretic-medications, blood-pressure-medications. Discuss these with a pharmacist before combining.

How do you know if you need Glycerol?

The marker is Plasma volume, osmolality, electrolyte balance, optimal range 4-7% increase in plasma volume post-loading. Common deficiency signs: Not applicable (not essential nutrient, used as ergogenic aid):, Conditions addressed by glycerol hyperhydration:, Poor heat tolerance and performance decline, Rapid dehydration during exercise.

Taken for

43 Performance

Caffeine · Creatine Monohydrate · Whey Protein