Glycerol is a naturally occurring alcohol. It is an odorless liquid that is used as a solvent, sweetening agent, and also as medicine.

When glycerol is in the intestines, it attracts water into the gut, softening stools and relieving constipation. When glycerol is in the blood, it attracts water so that the water stays in the body longer. This might help an athlete exercise for longer.

People use glycerol for constipation, improving athletic performance, and for certain skin conditions. It is also used for stroke, obesity, ear infections, and many other conditions, but there is no good scientific evidence to support these uses.

Glycerol is banned by the World Anti-Doping Agency (WADA).
When taken by mouth: Glycerol is possibly safe when used short-term. Side effects might include headaches, dizziness, bloating, nausea, and diarrhea.

When applied to the skin: Glycerol is likely safe. It might cause redness, itching, and burning.

When given in the rectum: Glycerol suppositories and enemas are likely safe and have been approved by the US Food and Drug Administration (FDA) for over-the-counter (OTC) use.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There isn't enough reliable information to know if glycerol is safe to use when pregnant or breast-feeding. Stay on the safe side and avoid use.

Children: Glycerol is likely safe when suppositories or enemas are inserted into the rectum in children at least 2 years of age. Glycerol is also likely safe when applied to the skin of children at least 1 month of age. Glycerol is possibly safe when taken by mouth, short-term in children 2 months to 16 years of age.


NatMed Pro rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
Likely effective Effectiveness definitions
  • Constipation. Using glycerol as a suppository or as an enema in the rectum decreases constipation in adults and children at least 2 years of age. It is US FDA approved for this use.
Possibly effective Effectiveness definitions
  • Athletic performance. Taking glycerol by mouth along with water helps to keep the body hydrated for longer during exercise. But it's not clear if this helps improve athletic performance.
  • An inherited skin disorder that causes dry, scaly skin (ichthyosis). Applying a specific product (Dexeryl, Pierre Fabre Laboratoires) containing glycerol and paraffin to the skin reduces symptoms like itching and scales in children with ichthyosis. It's not clear if applying glycerol alone helps.
Likely ineffective Effectiveness definitions
  • Stroke. Giving glycerol by IV doesn't improve symptoms after a stroke. IV products can only be given by a healthcare provider.
There is interest in using glycerol for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.
Possibly ineffective Effectiveness definitions
  • Swelling (inflammation) of membranes that protect the brain and spinal cord (meningitis). Taking glycerol by mouth doesn't reduce the risk of death or seizures in people with bacterial meningitis. But it might reduce the risk of deafness in children who survive the infection.
  • Growth and development in premature infants. Giving glycerol into the rectum, as a suppository or as an enema, doesn't seem to help premature infants start to take food by mouth sooner.
Insufficient evidence Effectiveness definitions

Dosing & administration

Glycerol has most often been used by adults in single doses of 1-1.5 grams/kg. It's also commonly used in over-the-counter (OTC) rectal enemas and suppositories, and in topical lotions. Speak with a healthcare provider to find out what type of product and dose might be best for a specific condition.

Interactions with pharmaceuticals

It is not known if Glycerol interacts with any medicines. Before taking Glycerol, talk with your healthcare professional if you take any medications.

Interactions with herbs & supplements

There are no known interactions with herbs and supplements.

Interactions with foods

There are no known interactions with foods.

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