Propylene Glycol



Propylene Glycol at a glance

  • Functions as a humectant (hydrating ingredient)
  • Can enhance the delivery of key actives into skin
  • Plays a role in keeping formulas from melting in high heat or freezing in low temps
  • Used in thousands of personal care products with a proven track record of safety
  • Also known as 1,2-propanediol

Propylene Glycol description

Propylene glycol is a humectant (hydrator) that can enhance the delivery of key active ingredients into skin. It also plays a role in keeping formulas from melting in high heat or from freezing in low temps. Also known as 1,2-propanediol, propylene glycol is used in thousands of personal care products with a proven track record of safety. As a raw material, it is a clear, purified liquid that is produced synthetically. There are some websites that state propylene glycol is really industrial antifreeze and that it is a strong skin sensitizer. They further point out that the Material Safety Data Sheet (MSDS) on propylene glycol warns users to avoid skin contact. As ominous as this sounds, it’s far from the reality of how propylene glycol is used in cosmetics formulations. The Cosmetic Ingredient Review Board and other groups have analyzed the toxicology data and exposure studies concerning topical application of propylene glycol as commonly used in cosmetics. Their conclusion was that it is safe and does not pose a health risk to consumers. Concentrations of up to 73% have been reported with leave-on products; for rinse-off products, higher concentrations are permissible.

Propylene Glycol references

  •, Accessed April 2021, ePublication
  • Archives of Dermatological Research, November 2019, pages 337-352
  • Critical Reviews in Toxicology, April 2013, pages 363-390
  • International Journal of Toxicology, September-October 2012, pages 245S-260S
  • Skin Pharmacology and Applied Physiology, 2001, pages 72-81

Peer-reviewed, substantiated scientific research is used to assess ingredients in this dictionary. Regulations regarding constraints, permitted concentration levels and availability vary by country and region.

Ingredient ratings


Proven and supported by independent studies. Outstanding active ingredient for most skin types or concerns.


Necessary to improve a formula's texture, stability, or penetration.


Generally non-irritating but may have aesthetic, stability, or other issues that limit its usefulness.


There is a likelihood of irritation. Risk increases when combined with other problematic ingredients.


May cause irritation, inflammation, dryness, etc. May offer benefit in some capability but overall, proven to do more harm than good.


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Not rated

We have not yet rated this ingredient because we have not had a chance to review the research on it.