What Is Peg-6 Sesqui(Benzotriazolyl T-Butyl Hydroxyphenylpropionate)?
Peg-6 Sesqui(Benzotriazolyl T-Butyl Hydroxyphenylpropionate) is a synthetic ingredient made by attaching short chains of polyethylene glycol (PEG-6) to a UV-absorbing molecule called benzotriazole t-butyl hydroxyphenylpropionate. The PEG part keeps the ingredient water-friendly while the benzotriazole section soaks up harmful light. Chemists first explored this blend in the late 1990s when the beauty industry started looking for ways to protect product color and active ingredients from breaking down in daylight. It is produced through a multi-step reaction that links the PEG chains to the benzotriazole core under controlled temperature and pH, followed by purification and drying.
You will most often spot this ingredient in leave-on products such as facial moisturizers, daily sunscreens, anti-aging serums, tinted creams and hair care creams that sit on the surface. It can also appear in rinse-off items like shampoos or shower gels when the brand wants extra shelf stability.
Peg-6 Sesqui(Benzotriazolyl T-Butyl Hydroxyphenylpropionate)’s Cosmetic Benefits/Uses
The main role of this ingredient is Light Stabilizer, meaning it helps the whole formula stay effective and look the same even when exposed to sunlight. By absorbing and scattering UV rays it slows down color fading, keeps fragrances intact and protects sensitive actives such as vitamins from breaking apart. This support lets the product perform as promised for a longer time while sitting on your bathroom shelf or during day-to-day wear.
Who Can Use Peg-6 Sesqui(Benzotriazolyl T-Butyl Hydroxyphenylpropionate)
This light stabilizer is generally well tolerated by most skin types including oily, dry, normal and combination skin because it sits on the surface and has a low likelihood of clogging pores or altering skin balance. People with highly sensitive or compromised skin should monitor use since the polyethylene glycol portion can sometimes heighten penetration of other ingredients that could irritate already fragile skin.
The molecule is fully synthetic and made without animal by-products so it is suitable for vegans and vegetarians. Cruelty status, however, depends on the individual brand’s testing policies.
No data suggests specific risks for women who are pregnant or breastfeeding when this ingredient is used topically and in the small amounts found in cosmetics. Absorption through intact skin is minimal, yet this is not medical advice and anyone expecting or nursing should show the product to a doctor before use just to be safe.
Peg-6 Sesqui(Benzotriazolyl T-Butyl Hydroxyphenylpropionate) does not cause photosensitivity. In fact it helps absorb UV light which can add a minor supportive shield for formulas, though it does not replace a dedicated sunscreen.
Potential Side Effects/Adverse Reactions
Responses to topical Peg-6 Sesqui(Benzotriazolyl T-Butyl Hydroxyphenylpropionate) vary from person to person. The points below outline potential, yet unlikely, reactions when the ingredient is formulated correctly.
- Mild redness or itching in very sensitive skin
- Rare contact allergy resulting in localized rash or hives
- Transient stinging if the product reaches the eyes
- Occasional breakout or folliculitis in individuals prone to congested pores
If any adverse reaction occurs discontinue use and seek advice from a qualified healthcare professional.
Comedogenic Rating
Rating: 1 / 5
The molecule is large and mainly sits on the skin surface while the PEG portion keeps it water friendly so it is unlikely to mix with skin oils or block pores. No published data links this light stabilizer to acne flare-ups and real-world reports of congestion are scarce. For most users including those prone to blackheads or pimples the risk of pore clogging is very low.
Suitable for acne-prone skin.
Because the ingredient can slightly enhance penetration of other formula components it is wise to consider the overall product when judging breakout potential rather than this single stabilizer.
Summary
Peg-6 Sesqui(Benzotriazolyl T-Butyl Hydroxyphenylpropionate) acts as a light stabilizer that absorbs and scatters UV rays to guard the entire formula against color fading fragrance loss and active degradation. The PEG side keeps the molecule dispersible in water based systems while the benzotriazole core does the heavy lifting by soaking up damaging light.
It is a niche additive used mostly by brands that want extra product longevity so you will not find it in every lotion or serum yet it appears with growing frequency in modern multitaskers like day creams and tinted moisturizers.
Topical safety is high with only rare reports of mild irritation. As with any new cosmetic it is smart to patch test first especially if you have sensitive or reactive skin.