Glycerol
OTHER NAME(S): glycerin, glycerine, glycerol
Overview
Glycerol is a sweet-tasting liquid that can be consumed in a drink or applied to the skin. It is also added to many products, including foods, drinks, and cosmetics. Some people drink glycerol to help prevent dehydration from a workout and improve physical performance, but its benefits for these uses are not well defined. Common side effects include bloating, nausea, and headache. Children are at higher risk for serious side effects from oral glycerol. Topical products that contain glycerol are usually well tolerated and may help improve the appearance of the skin and hair. Before taking glycerol by mouth, tell your health care provider about all of your health conditions and any medicines or supplements you may be using.
Uses
What is glycerol used for?
Glycerol is used topically to improve the appearance of the skin and hair.
Oral glycerol is sometimes used to improve physical performance and prevent dehydration during an intense workout. However, its benefits for these uses are not well defined.
Glycerol may also be used for other conditions as determined by your health care provider.
Note: Glycerol is available as a dietary supplement. It is also added to foods, drinks, cosmetics, and medicines. It is generally recognized as safe (GRAS) by the FDA for use in foods. Learn more about GRAS status here. The FDA has not reviewed other glycerol products for safety and effectiveness. Learn more about cosmetics here. Learn more about dietary supplements here.
See also: Glycerin Ophthalmic and Glycerin Rectal
How does glycerol work (mechanism of action)?
Glycerol is a type of sweet-tasting chemical called sugar alcohol. It is the same chemical as glycerin. However, glycerol is the pure form of the chemical. Glycerin, on the other hand, contains water and other substances, so it is only 95%-99.5% pure.
A wide range of products, including foods, drinks, and medicines, contain glycerol. It is most often added to these products as an emulsifier, sweetener, or preservative. It is also added to many cosmetics and skin care products as a humectant, meaning that it can help keep the skin and hair hydrated. It may also protect against irritating chemicals. Due to these effects, products that contain glycerol may help to improve the appearance of your skin or hair.
Some athletes drink glycerol along with large amounts of water before an intense workout or competition to help prevent dehydration. This is because glycerol tells your kidneys to increase the amount of water in your body by reducing how often you pee. While this does seem to keep people hydrated for longer, the effect is very small. This means that adding glycerol to water before a workout may only be helpful for elite athletes.
It is not clear if glycerol can help improve physical performance during exercise. It is possible that any benefits from drinking glycerol are related to its hydration effects. For example, staying better hydrated may allow a long-distance cyclist or professional runner to continue for longer. More research is needed to understand whether glycerol can improve physical performance in other ways or in non-elite athletes.
How should I store glycerol?
You should store glycerol according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.
Side Effects
What are the most common side effects of glycerol?
Topical glycerol appears to be well tolerated. The most common side effects of oral glycerol are listed below. These side effects may vary depending on the dose you are taking or the specific product you are using. Tell your health care provider if you have any of these side effects that bother you.
- Bloating
- Headache
- Nausea
There may be other side effects of glycerol that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.
What are the serious side effects of glycerol?
While less common, the most serious side effects of glycerol are described below, along with what to do if they happen.
Severe Allergic Reactions. Glycerol may cause allergic reactions, which can be serious. Stop using glycerol and get help right away if you have any of the following symptoms of a serious allergic reaction.
- Breathing problems or wheezing
- Racing heart
- Fever or general ill feeling
- Swollen lymph nodes
- Swelling of the face, lips, mouth, tongue, or throat
- Trouble swallowing or throat tightness
- Itching or skin rash
- Bumps on the skin called hives, which can be red, pink, white, or brown depending on your skin tone
- Nausea or vomiting
- Dizziness, feeling lightheaded, or fainting
- Stomach cramps
- Joint pain
Precautions
Who should not use glycerol?
Allergies to Ingredients. People who are allergic to any of the following should not use glycerol.
- Glycerin
- Glycerol
- Any of the ingredients in the specific product
Your pharmacist can tell you all of the ingredients in the specific glycerol products they stock.
What should I know about glycerol before using it?
Glycerol is available as a liquid dietary supplement. It is also added to many foods, drinks, cosmetics, and medicines. It cannot be marketed to treat or cure a disease.
Read and follow the directions on the specific product you are using, or use it as recommended by your health care provider.
Keep glycerol out of the reach of children. Children are at higher risk for side effects from oral glycerol. Glycerol is found in certain flavored drinks, especially slushy ice drinks (slushies). Experts recommend that children under 7 years of age should avoid slushies completely. Children who are between 7 and 10 years of age should not drink more than about 1.5 cups (12 ounces) of slushy ice drinks in one day. Speak with a health care provider if you have any questions or concerns.
If you are taking liquid glycerol, use an accurate measuring device to measure your dose. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Ask your pharmacist what measuring device to use.
The FDA has not tested glycerol products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.
What should I tell my health care provider before using glycerol?
Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if glycerol is right for you.
In particular, make sure that you discuss any of the following.
Current and Past Health Conditions.Tell your health care provider if you have any of the following.
- Diarrhea
- Heart problems, including heart failure
- High or low blood pressure
- Kidney or liver problems
Other Medicines and Supplements.Glycerol may interact with other medicines and supplements. Before taking glycerol, tell your health care provider about any prescription or OTC medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.
Pregnancy. It is not known if or how glycerol could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant.
Breastfeeding. It is not known if glycerol passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.
Interactions
Does glycerol interact with foods or drinks?
There are no known interactions between glycerol and foods or drinks, but caffeine and glycerol may have opposite effects. Caffeine is found in many common foods and drinks (such as coffee, tea, soda, chocolate, and some protein bars).
It is unknown if drinking alcohol will affect glycerol.
Does glycerol interact with medicines (drug interactions)?
Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.
In particular, make sure that you discuss if you are using any of the following before taking glycerol.
- A diuretic, also called a water pill, which is a medicine used to reduce edema (fluid retention) and blood pressure
- Any product that contains caffeine, which is often found in supplements and medicines for reducing water weight (diuretics), staying awake, headaches, and hangover relief
The interactions between glycerol and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with glycerol is incomplete. Always check with your health care provider before taking glycerol with any medicines.
Dosing
What should I do if I accidentally use too much glycerol?
If you or someone else has used too much glycerol, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.
Glycerol is found in many foods, drinks, cosmetics, and medicines. It is also available as a liquid to drink or place on the skin. Read the product label closely, and speak with a health care provider about how to use glycerol safely. Do not use double or extra doses, even if you miss a dose.
References
- Medicine and Science in Sports and Exercise: “American College of Sports Medicine position stand: exercise and fluid replacement.”
- Archives of Disease in Childhood: “Glycerol intoxication syndrome in young children, following the consumption of slush ice drinks.”
- International Journal of Toxicology: “Safety assessment of glycerin as used in cosmetics.”
- EFSA Journal: “Re‐evaluation of glycerol (E 422) as a food additive.”
- Food Standards Agency (UK): “Slush ice drinks containing glycerol.”
- Frontiers in Nutrition: “Effects of glycerol hyperhidration on the running economy of long-distance runners: a randomized crossover clinical trial.”
- International Journal of Sports of Physiology and Performance: “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.”
- Journal of the International Society of Sports Nutrition: “Effects of pre-exercise glycerol supplementation on dehydration, metabolic, kinematic, and thermographic variables in international race walkers.”
- Journal of Strength and Conditioning Research: “Effects of exercise induced dehydration and glycerol rehydration on anaerobic power in male collegiate wrestlers.”
- World Anti-Doping Agency: “Summary of major modifications and explanatory notes: 2018 prohibited list.”