What Is Glycereth-31?
Glycereth-31 is a water-loving liquid made by attaching about 31 units of ethylene oxide to glycerin, the same gentle humectant found in plants and many skincare staples. This process, called ethoxylation, turns simple glycerin into a smoother more flexible ingredient that mixes well with both water and oil. First explored in the late twentieth century as chemists looked for milder alternatives to harsh solvents, Glycereth-31 quickly earned a spot in personal care labs thanks to its soft feel and strong moisture-binding talent.
To manufacture it, glycerin is placed in a reactor, combined with controlled amounts of ethylene oxide gas then neutralized and purified. The result is a clear slightly viscous liquid that dissolves fast in water and stays stable over a wide pH range. Because of these traits you will often see it in facial masks, lightweight moisturizers, soothing after-sun gels, cream cleansers, micellar waters, anti-aging serums and even hair conditioners where it helps hold hydration and improve texture.
Glycereth-31’s Cosmetic Benefits/Uses
Formulators prize Glycereth-31 for several practical roles that improve how a product feels acts and lasts
- Humectant – attracts water from the environment and from deeper skin layers then locks it at the surface giving skin a plump comfortable feel without greasiness
- Skin Conditioning – smooths rough patches and supports the skin barrier which can reduce the look of fine lines and flakiness
- Cleansing – boosts the mild cleansing power of surfactants helping wash away dirt and makeup while staying gentle on skin
- Viscosity Controlling – fine tunes the thickness of gels lotions or micellar waters so they spread easily yet stay stable on the shelf
Who Can Use Glycereth-31
Thanks to its mild nature and water-binding skill Glycereth-31 suits nearly every skin type including dry thirsty skin that craves moisture, oily or breakout-prone skin that wants light hydration, combination skin and most sensitive complexions because it has no fragrance or harsh solvents. Only those with a known allergy to polyols or a severely compromised barrier should proceed with extra caution as even gentle humectants can occasionally draw water out of very damaged skin.
The glycerin used to make Glycereth-31 is typically sourced from vegetable oils so the finished ingredient is generally suitable for vegans and vegetarians. If a formula is labeled vegan you can assume the supplier has confirmed a plant origin.
Current safety data show no reproductive or developmental concerns from topical use and the molecule is too large to penetrate deeply, so products with Glycereth-31 are widely considered safe for people who are pregnant or breastfeeding. This is not medical advice and anyone expecting or nursing should still run new skincare past a doctor to be safe.
Glycereth-31 does not increase photosensitivity so it will not make skin more prone to sunburn. As always daily sunscreen is recommended for overall skin health.
Potential Side Effects/Adverse Reactions
Responses to any cosmetic ingredient differ from person to person. The issues below are possible yet uncommon when Glycereth-31 is correctly formulated and used in typical amounts
- Mild transient redness or tingling in very sensitive skin, usually subsiding quickly once the product dries
- Rare allergic contact dermatitis presenting as itching or small bumps when an individual is specifically sensitized to polyethoxylated compounds
- Stinging on broken or freshly exfoliated skin because humectants can pull water from deeper layers toward the surface
- Eye irritation if a high concentration gets into the eyes, more likely in cleansing products than in leave-on skincare
If any irritation or other negative effect occurs stop using the product and seek guidance from a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 0 (non-comedogenic). Glycereth-31 is a large water-soluble molecule that does not sit in pores or form an occlusive film, so it is highly unlikely to trap sebum or debris. It also rinses off easily when used in cleansers and remains lightweight in leave-on formulas, further reducing any pore-clogging risk. In practical use and in the available literature no link has been found between Glycereth-31 and increased blackheads or breakouts.
Because of this low rating, products featuring Glycereth-31 are generally suitable for acne-prone or breakout-prone skin.
One point worth noting is that the overall comedogenicity of a finished product depends on the full recipe. If Glycereth-31 is paired with heavy oils or waxes, those other ingredients could still trigger congestion even though Glycereth-31 itself will not.
Summary
Glycereth-31 acts as a humectant, skin conditioner, gentle cleanser booster and viscosity controller. Its chain of ethylene oxide units grabs water molecules and keeps them near the skin surface, softening and smoothing without greasiness. The same structure helps stabilize surfactant micelles in cleansers and fine-tunes the texture of gels and lotions so they feel silky yet stay shelf-stable.
While not as famous as hyaluronic acid or traditional glycerin, Glycereth-31 is quietly popular among formulators looking for a no-nonsense hydrator that also improves spreadability. You will most often spot it in mid-priced facial mists, light moisturizers and micellar waters rather than in headline marketing claims.
Current safety data show it to be low risk for irritation, sensitization or systemic absorption, which is why it appears in sensitive-skin lines and baby care. Still, skin can be unpredictable, so performing a small patch test with any new product is a smart precaution before full-face use.