What Is Polyester-16?
Polyester-16 is a synthetic polymer that starts with four building blocks: dimethyl sodiosulfoisophthalic acid, dimethyl terephthalate, ethylene glycol and isophthalic acid. When these small molecules react together they form long, flexible chains. The final material is turned into its sodium salt form so it can mix well with water-based formulas.
The idea of using polyester chemistry in beauty products grew out of the textile industry where similar polymers create smooth durable fibers. In the 1990s formulators noticed that certain sulfonated polyesters could form clear breathable films on skin and hair. Over time the recipe was refined into what we now call Polyester-16, which earned a place in rinse-off cleansers and leave-on products for its gentle feel and quick-dry finish.
Manufacturing begins in large stainless steel reactors. The four starter ingredients are heated under precise temperature and pressure until they link together. After purification the thick resin is neutralized with a small amount of sodium, dried then milled into a fine powder or dissolved in water for easy use by cosmetic chemists.
Today Polyester-16 shows up in facial masks, liquid and bar cleansers, micellar waters, makeup setting sprays, light lotions, styling gels and some long-wear foundations where a flexible film helps pigment stay put.
Polyester-16’s Cosmetic Benefits/Uses
This ingredient earns its spot on an ingredient list for two main reasons
- Film forming: Once applied it dries into a thin invisible layer that locks moisture in, holds active ingredients where they are needed and gives makeup and hair products longer wear without a heavy feel
- Cleansing: The sulfonated parts of the polymer attract oil and dirt while the sodium salt makes it water loving, so it lifts grime from skin or hair and rinses away cleanly leaving a soft finish
Who Can Use Polyester-16
Polyester-16 is gentle enough for most skin types. Dry and normal skin benefit from the light breathable film that helps hold moisture while oily and combination skin appreciate that the polymer feels weightless and rinses clean without leaving a greasy residue. Very sensitive or allergy-prone skin can usually tolerate it but anyone with a known sensitivity to synthetic polymers should proceed carefully.
The ingredient is man-made and contains no animal by-products so it is suitable for both vegans and vegetarians.
Current data shows no specific risks for women who are pregnant or breastfeeding when Polyester-16 is used in topical products. This is not medical advice and anyone who is expecting or nursing should run all skincare choices past a qualified doctor to be safe.
Polyester-16 does not make skin more reactive to sunlight and therefore is not considered photosensitising. It can be worn in daytime products without raising concern as long as normal sun protection habits are followed.
There are no known interactions with common actives like retinoids, vitamin C or exfoliating acids. It layers well in multi-step routines and washes out of hair without interfering with color treatments.
Potential Side Effects/Adverse Reactions
Side effects from topical Polyester-16 vary from person to person. The points below list potential reactions yet they are uncommonly reported. When the ingredient is used at the levels allowed in cosmetics most users experience no problems.
- Temporary redness or warmth on very reactive skin
- Mild itching or tightness if the film is applied too thickly
- Flaking or buildup on hair shafts with heavy repeated use
- Contact dermatitis in individuals allergic to synthetic polyesters
- Eye stinging if the product is accidentally rubbed into the eyes before it dries
If any uncomfortable reaction occurs stop using the product and consult a healthcare professional or pharmacist for further guidance.
Comedogenic Rating
Rating: 1/5
Polyester-16 forms a breathable water-friendly film that sits on top of skin rather than sinking into pores. The polymer chains are too large to clog follicles and they rinse off cleanly in wash-off formats. Leave-on products that also contain heavy oils could still pose a clogging risk but Polyester-16 itself is low on the scale.
Suitable for acne-prone or breakout-prone users in most formulas.
Because the ingredient can trap other materials underneath its film, overly rich creams or makeup layered beneath it might contribute to congestion for some users. Choosing lightweight companions minimizes that possibility.
Summary
Polyester-16 is mainly a film former and mild cleanser. It builds a thin flexible layer that locks in moisture, keeps pigments or actives where they belong and boosts wear time. Its sulfonated sections attract oil and dirt while the sodium salt side loves water so it lifts grime and rinses away without residue.
The polymer enjoys moderate popularity. It shows up in setting sprays, micellar waters and long-wear makeup but is less common than silicones or traditional surfactants because it is newer and costs more to produce.
Current safety data marks Polyester-16 as low risk with only rare reports of irritation or allergy. As with any new cosmetic ingredient it is smart to patch test a product before full use to be safe.