What Is Peg-15 Glyceryl Triisostearate?
Peg-15 Glyceryl Triisostearate is a lab made ingredient created by attaching about fifteen units of ethylene oxide to glyceryl triisostearate, a molecule that comes from glycerin and isostearic acid, a fatty acid usually sourced from vegetable oils like rapeseed or soybean. The result is a waxy liquid that mixes oil loving and water loving parts in one structure.
Chemists first explored this type of molecule in the late 20th century when the cosmetics industry needed gentler, more versatile alternatives to animal based fats and harsh detergents. The “PEG” section refers to polyethylene glycol, which boosts water solubility, while the glyceryl triisostearate piece gives the ingredient a rich, oil like feel.
Manufacturing starts with food grade vegetable oil that is split to isolate isostearic acid. This acid is reacted with glycerin to form glyceryl triisostearate. The finished fat is then treated with ethylene oxide in a controlled setting to build the PEG chain. Each step is purified and filtered to meet cosmetic safety standards.
Because it can hold oil and water together and leave skin soft, Peg-15 Glyceryl Triisostearate shows up in a wide range of products such as facial cleansers, makeup removers, creamy sunscreens, hydrating masks, body lotions, color cosmetics and anti aging serums. Its smooth texture also helps spread pigments evenly in foundations and lipsticks.
Peg-15 Glyceryl Triisostearate’s Cosmetic Benefits/Uses
This multitasker improves both the feel and stability of many formulas.
- Emollient: Creates a silky, cushioned finish that makes skin feel soft and supple while helping to reduce moisture loss
- Emulsifying: Binds oil and water into a stable blend so creams stay uniform, do not separate and deliver active ingredients evenly
Who Can Use Peg-15 Glyceryl Triisostearate
Because it is lightweight yet richly conditioning, Peg-15 Glyceryl Triisostearate suits most skin types including normal, dry and combination. Those with very oily or easily congested skin might prefer lower-fat formulas since the fatty acid portion could feel heavy in high concentrations.
The ingredient is produced from plant oils and petrochemical ethylene oxide with no animal derived matter, making it appropriate for vegans and vegetarians.
Current safety assessments show no special risks for use during pregnancy or while breastfeeding. This is not medical advice; anyone who is pregnant or nursing should ask a physician before introducing new personal care products just to be safe.
Peg-15 Glyceryl Triisostearate does not cause photosensitivity, so it will not increase the chance of sunburn. It is also fragrance free and rarely interacts negatively with other common actives, which helps it fit smoothly into most routines.
Potential Side Effects/Adverse Reactions
Responses to topical Peg-15 Glyceryl Triisostearate differ from person to person. The effects below are possible but not expected for the average user when the ingredient is properly formulated.
- Mild skin irritation redness or stinging on very sensitive skin, usually short lived
- Contact allergy rare cases of itching or rash due to an immune response to the PEG portion
- Eye irritation watering or discomfort if a product accidentally gets into the eyes
- Pore congestion potential for breakouts in individuals highly prone to acne when used in heavy leave-on products
- Trace 1,4-dioxane contamination an impurity that can form during PEG production but is minimized by reputable manufacturers
Stop using the product and seek medical advice if any of these reactions occur or persist.
Comedogenic Rating
Rating: 2/5
The isostearic acid portion has a mildly oily character that can sit on the skin, while the PEG side improves water solubility and keeps the molecule from feeling overly greasy. Together they land Peg-15 Glyceryl Triisostearate in the low to mid range for pore clogging potential. It is generally fine for acne prone skin when used in light or rinse-off products, but very rich leave-on formulas containing high levels could still trigger breakouts for some.
Final texture, concentration and the presence of other heavy oils in the formula play a bigger role in clogging risk than the ingredient itself.
Summary
Peg-15 Glyceryl Triisostearate acts as an emollient that softens and cushions the skin and as an emulsifier that locks oil and water into a smooth stable blend. Its fatty tail delivers the silky feel while the PEG chain grabs onto water, so the whole molecule bridges the gap between the two phases.
It shows up regularly in cleansers, creams, sunscreens and makeup but it is more of a quiet workhorse than a headline-grabbing active. Formulators like it because it is easy to use, gives good slip and plays well with most other ingredients.
Safety reviews rate it as low risk with only rare irritation or allergy reports. Even so, skin can be unpredictable so testing any new product on a small area first is always smart.