Propylene glycol on an ingredient list: what Healthline and DermNet say

Reviewed October 17, 2026

The short answer

Propylene glycol is a lab-made alcohol found in plenty of moisturizers, deodorants and hair products. Healthline quotes dermatologists who consider it fine for the general population. DermNet, a dermatology reference, treats it as a recognised trigger of allergic skin reactions, though a minority are affected. Both sources advise caution for eczema-prone or touchy skin.

What is it?

DermNet calls it a syrupy, colourless, scentless liquid of low toxicity, serving as moisture-holder, solvent, emulsifier, softener and penetration booster. On labels, per Healthline, you may also see methyl glycol or trimethyl glycol, and per DermNet propane-1,2-diol.

What does it do in a product?

• Healthline: antimicrobial properties help a product last longer.
• Healthline, quoting a dermatologist: in small amounts it boosts a moisturizer because it strongly attracts water.
• Healthline: active ingredients can soak into skin more easily with it present.
• DermNet: it also appears in topical medicines and some foods.

The safety debate

Healthline notes frightening wording online and traces part of it to propylene glycol commonly coming from petroleum and being used in things like antifreeze. Two dermatologists it quotes say the cosmetic form is nothing to worry about and chemically inactive. Healthline also reports that the Environmental Working Group rates it "fair", sees no cancer or developmental risk, and links it to irritation and contact dermatitis from as little as 2 percent.

Contact allergy

• DermNet: true allergy is fairly rare, seen in as many as 3.5% of people tested because of suspected contact dermatitis. The relevant US allergy society named it its allergen of 2018.
• DermNet: roughly 38% of the products in a 2016 allergen database contained it, and it is described as the leading allergen found in topical steroid products.
• DermNet: reactions may be likelier on atopic or otherwise compromised skin, mostly appearing on the face. It also commonly triggers irritation rather than allergy, and in rare cases a body-wide reaction.
• Healthline, quoting a dermatologist: allergic skin reactions are not unusual, particularly with eczema, past allergies or sensitive skin.

Patch testing and what to do

Healthline describes a home test: dab a little product onto nearby skin, leave it a full day or more, then check for swelling, itching or irritation. It says to stop a new product and see a dermatologist for inflammation, bumps, hives, discoloration, itching or stinging. DermNet says a dermatologist can confirm an allergy with patch testing, and that steering clear of it is the main treatment once found. DermNet adds that polyethylene glycol is a different substance and does not cross-react.

How to read it on a label

US cosmetic labels generally list ingredients in descending order of amount, but anything at 1% or less can appear in any order after those above 1%. Its position does not tell you the exact concentration. Judge the whole product, how it feels on your skin, and what changes when you add or drop it.

What not to conclude

This page does not say propylene glycol is safe or unsafe for you. The sources emphasize different things, and DermNet says even the best patch-test strength for it is still debated. If a product with it irritates your skin, stop using it and ask a dermatologist.