What Is Peg-45 Stearate?
Peg-45 Stearate is a synthetic ingredient made by attaching about 45 units of ethylene oxide to stearic acid, a fatty acid most often sourced from vegetable oils like coconut or palm. This process, called ethoxylation, produces a water loving chain that is then esterified to the oil loving stearic acid, creating a molecule that bridges both water and oil phases. Polyethylene glycol stearates first appeared in cosmetics in the 1950s when formulators were looking for stable alternatives to natural soaps that could handle a wider pH range. Since then Peg-45 Stearate has become a staple in products that need reliable texture and rinse off performance. You will typically see it in facial cleansers, makeup removers, moisturizers, sunscreens, sheet mask essences and creamy foundations where it helps blend water and oil while giving a smooth feel.
Peg-45 Stearate’s Cosmetic Benefits/Uses
Formulators choose Peg-45 Stearate for two main reasons
- Cleansing: Its balanced water and oil affinity helps lift away dirt, excess sebum and makeup while allowing the residue to rinse off easily with water. This makes washes and makeup removers feel gentle yet effective, reducing the need for harsher surfactants.
- Emulsifying: It keeps oil and water mixed evenly so creams and lotions stay uniform from the first pump to the last. A stable emulsion improves product shelf life, texture and overall sensory feel, preventing separation or greasy afterfeel.
Who Can Use Peg-45 Stearate
Peg-45 Stearate is generally well tolerated by most skin types. Its mild cleansing action makes it friendly for normal, dry, oily and combination skin. Sensitive skin usually does fine with it because it is considered a low irritant, but as with any surfactant very reactive skin may prefer formulas that keep its level low and add soothing agents.
The ingredient itself is synthetic, yet its stearic acid portion can come from either plant or animal fat. Many cosmetic suppliers use coconut or palm sources, making the finished material suitable for vegans and vegetarians. Labels or brand FAQs often clarify the origin so those following a strict plant based lifestyle may want to verify sourcing.
There is no evidence that Peg-45 Stearate poses special concerns for pregnant or breastfeeding women when used topically. Still, this is not medical advice. Anyone who is pregnant or nursing should review all skincare choices with a doctor to be safe.
Peg-45 Stearate is not known to cause photosensitivity so it will not make skin more prone to sunburn. It also plays nicely with most other common cosmetic ingredients, including acids, retinoids and sunscreens.
Potential Side Effects/Adverse Reactions
Side effects from topical Peg-45 Stearate vary from person to person. The points below list potential reactions, yet they are uncommon when the ingredient is used at the levels found in finished products.
- Minor skin irritation such as temporary redness itching or stinging, usually in very sensitive skin
- Allergic contact dermatitis in individuals allergic to polyethylene glycols or stearates
- Eye irritation if a cleanser or cream accidentally gets into the eyes
- Dryness or tight feeling when used in high foaming formulas without added moisturizers
If any negative reaction occurs stop using the product and consult a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 1 / 5
Peg-45 Stearate is classified as low comedogenic because its large polyethylene glycol chain keeps the fatty stearic acid portion from building up inside pores. Studies and formulator feedback show little to no clogging even at the higher percentages used in cleansers or creams. The rating reflects that it is still a fatty ester, so a very small risk exists for extremely congestion-prone skin, but overall it is considered safe for breakout-prone users.
Suitable for people who are prone to acne or blackheads thanks to its quick rinse-off nature and low residue.
Comedogenicity can rise if a formula pairs Peg-45 Stearate with heavy occlusive oils and waxes, so the whole ingredient list matters when evaluating a product.
Summary
Peg-45 Stearate is mainly used to cleanse and emulsify. Its water-loving PEG chain lifts dirt and makeup while the oil-loving stearic acid end grabs oily debris, letting everything rinse away easily. The same dual character binds water and oil into a smooth stable emulsion that keeps creams uniform and pleasant to spread.
The ingredient is a reliable workhorse found in face washes, lotions, sunscreens and makeup removers. It is not a trending buzzword yet it remains popular among chemists who need a gentle versatile helper that rarely causes drama.
Safety reviews rate it as low irritant with minimal allergy reports. Most skin types can use it without issues though anyone trying a new product should still patch test first to rule out personal sensitivities.