What is Propylene Glycol?
Propylene glycol (PG) is a colorless, odorless, viscous liquid with remarkable versatility. It's a solvent (dissolves other ingredients), a humectant (draws moisture to skin), and a preservative booster. You'll find it in moisturizers, serums, foundations, deodorants, toothpaste, hair products, and even in foods and pharmaceuticals.
Because it's cheap, effective, and well-tolerated by most people, propylene glycol has become one of the most common ingredients in personal care. That very ubiquity is part of the problem: if you're allergic, avoiding it requires vigilance.
Why does Propylene Glycol cause reactions?
Propylene glycol can cause both irritant and allergic contact dermatitis. As an irritant, it may cause stinging or dryness in people with damaged or sensitive skin, especially at high concentrations or in occlusive formulations. As an allergen, it sensitizes some people through repeated exposure, leading to true allergic contact dermatitis.
The American Contact Dermatitis Society named it Allergen of the Year 2018 because patch test positivity rates had been climbing. The more products contain PG, the more people are exposed — and the more sensitization occurs. Leave-on products (moisturizers, serums) pose greater risk than rinse-off products because exposure time is longer.
Propylene glycol can also enhance the penetration of other ingredients, which may increase the risk of sensitization to other allergens in the same product.
In Indian products 🇮🇳
Propylene glycol is extremely common in Indian skincare and cosmetics. Budget and premium brands alike use it as a workhorse ingredient. Popular moisturizers, serums, and makeup from both international and domestic brands typically list it in the first half of the ingredient list.
Indian dermatologists report propylene glycol as a meaningful allergen in patch test series. If you've tried multiple "sensitive skin" products and still experience reactions, PG could be the shared culprit. Look for brands like Minimalist, The Derma Co, or other options that offer PG-free formulations.
How to avoid Propylene Glycol
- Read every label — PG appears under "Propylene Glycol," "1,2-Propanediol," or "Propane-1,2-diol." It's often in the first 10 ingredients.
- Check all product categories — Don't overlook deodorant, toothpaste, hair gel, or medications. Topical steroids and other prescription creams sometimes contain PG.
- Use ingredient apps — Apps like CosDNA or INCIDecoder can flag PG. AllerNote's ingredient checker can help identify it across your routine.
- Request patch testing — If you suspect PG allergy, a dermatologist can confirm with patch testing. Avoidance is much easier once you have a clear diagnosis.
- Beware of "propylene glycol-free" claims — Some products replace PG with similar compounds (e.g., butylene glycol, pentylene glycol) that may cross-react in highly sensitive individuals.
Safer alternatives
- Humectants: Glycerin, hyaluronic acid, sodium hyaluronate, sorbitol, and xylitol can provide similar moisture-drawing effects without PG.
- Solvents: Ethanol, propanediol (different from propylene glycol), or water-based formulations without glycols.
- Brands: Look for "propylene glycol-free" or "sensitive skin" lines. Some Korean and Japanese brands offer glycol-free options. Always verify by reading the full ingredient list.