What Is Polyester-28?
Polyester-28 is a synthetic polymer created by linking siloxane units with fatty acid dimers and propylene glycol esters. The full chemical description, “Siloxanes and Silicones di-Me 3-hydroxypropy group-terminated polymers with C18-unsaturated fatty acid dimers and propylene glycol bis(2-octyl-1-dodecyl)esters,” reveals three key building blocks: silicone segments that give flexibility, long-chain fatty acids that add richness and propylene glycol esters that improve spreadability. Chemists first explored this hybrid structure in the early 2000s while searching for lightweight alternatives to heavy waxes and oils. Because the silicone backbone resists water and the fatty acid branches love it, the finished polymer forms a breathable shield on skin or hair, making it attractive to beauty formulators.
Manufacturing begins with a controlled reaction where dimethicone molecules are “capped” with hydroxypropyl groups. These capped silicones are then coupled with dimerized C18 fatty acids and esterified with propylene glycol derivatives. The stepwise process is carried out in closed reactors at moderate temperatures, yielding a clear viscous fluid that is filtered and quality-checked before it is shipped in drums.
You will most often see Polyester-28 in leave-on facial moisturizers, hair serums, foundations, primers, sunscreens, sheet masks and soothing after-sun gels. Brands favor it when they want a soft touch finish without the greasiness of mineral oils.
Polyester-28’s Cosmetic Benefits/Uses
Polyester-28 is prized mainly for one job in formulas
As a film former it lays down an invisible flexible layer that locks in moisture, smooths rough texture and helps active ingredients stay put longer. The film also scatters light slightly creating a soft-focus effect on skin while reducing frizz and adding gloss on hair.
Who Can Use Polyester-28
Polyester-28 is generally suitable for all skin types. Its light breathable film helps dry skin hold water while not feeling heavy on oily or combination skin. Sensitive users also tend to tolerate it because the polymer is inert and fragrance free. Those with extremely acne prone skin who struggle with any kind of coating agent may want to monitor how their skin responds.
The ingredient is fully synthetic and does not come from animal sources so it is considered vegan and vegetarian friendly. Most suppliers also list it as cruelty free but consumers should still check the finished brand’s stance on animal testing.
Current safety data show no known risks for pregnant or breastfeeding women when Polyester-28 is used topically. The molecule is large and unlikely to penetrate deeply. That said this is not medical advice and anyone who is pregnant or nursing should run all skincare products past a qualified doctor first to be on the safe side.
Polyester-28 does not cause photosensitivity and can be worn during the day without raising sun sensitivity. It also plays well with common actives like retinol or vitamin C because it forms a stable, non reactive layer.
Potential Side Effects/Adverse Reactions
Side effects from topical Polyester-28 vary from person to person. The points below cover potential reactions but most users will not experience them when the ingredient is formulated and applied correctly.
- Mild skin irritation such as redness or itching in individuals who are highly sensitive to silicones
- Temporary clogged pores or small breakouts in users who are very prone to acne and who apply heavy layers repeatedly
- Contact dermatitis triggered by an allergy to a co-ingredient in the same product, not the polymer itself
- Eye irritation if the product accidentally gets into the eyes
- Buildup on hair shafts leading to dullness if not washed out over time
If any of these effects occur stop using the product and seek advice from a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 1 / 5
Polyester-28 earns a low score because its large silicone-fatty acid structure sits mainly on the surface and does not mix with skin’s natural sebum, making it less likely to clog pores. While the light occlusive film can trap debris if layered heavily on already congested skin, typical use in well-balanced formulas poses little risk.
Overall this ingredient is usually fine for acne-prone users, though extremely blemish-sensitive individuals may prefer to limit thick or overnight applications.
Worth noting: formula context matters. When combined with heavy butters or waxes, total pore-blocking potential can rise, so assess the whole product not just one ingredient.
Summary
Polyester-28 is a synthetic film former that locks in moisture, improves texture and helps actives stay put by creating a flexible breathable shield on skin or hair. It smooths rough spots, softens light and boosts gloss without the greasy feel of traditional oils.
Although not a headline-grabbing star, it has carved out a steady place in primers, tinted moisturizers and shine-boosting hair serums where a weightless silky finish is valued.
Current research shows it is low-irritation, non-sensitizing and vegan friendly. Still, skin is personal so it is wise to patch test any new product containing Polyester-28 before full use.