Avobenzone
Skincare ingredient, decoded — every claim sourced.
What it is
An organic (chemical) UV filter that absorbs UVA light, the wavelengths most associated with the look of premature skin aging and uneven tone. It is the most widely used dedicated UVA filter in US sunscreens.
How it works
Avobenzone (a dibenzoylmethane derivative) absorbs UVA light, with peak absorption around 357 nm, covering most of the UVA range that other older filters miss. It works by sitting mainly in its enol form, which absorbs the high-energy UVA photon and re-releases that energy as harmless heat. The catch: under UV light some of the molecule shifts (via keto-enol tautomerism) into a longer-lived excited keto state that can break down, so a fresh layer steadily loses UVA-absorbing power. This is why cosmetic formulas pair it with photostabilizers that quench that excited state, such as octocrylene, bemotrizinol (Tinosorb S), bisoctrizole (Tinosorb M) or ecamsule (Mexoryl SX), so the protection lasts across real-world sun exposure.
Works well with
Octocrylene (photostabilizer)Bemotrizinol / Tinosorb SBisoctrizole / Tinosorb MEcamsule / Mexoryl SXAntioxidants (vitamin E, vitamin C) as supportive stabilizers
Introduce carefully alongside
Uncoated zinc oxide or titanium dioxide (in mixtures, uncoated mineral filters can accelerate avobenzone photodegradation under UV; particle coatings reduce this)Iron / ferric salts (can cause discoloration and destabilize it)Octinoxate (octyl methoxycinnamate) without an added stabilizer (the two undergo concomitant photolysis, so each speeds the other's breakdown)
Who should take care
Anyone with a known allergy or photoallergy to avobenzone or other dibenzoylmethane filters should skip it; it is among the more frequently reported sunscreen photoallergens (oxybenzone is the single most reported), though true reactions remain uncommon and are often traced to other ingredients in the formula. People who prefer purely mineral (zinc oxide / titanium dioxide) sunscreens, or who react to the photostabilizers it is usually paired with, may also want to choose alternatives. Not a reason for fear, just a personal-fit note.
🔒 IN THE APP
The dose that actually works — and is it right for your skin?
The concentration that actually makes a difference, and whether this fits YOUR skin profile, lives in the MHS BLOOM app.
Sources
- FDA Final Administrative Order OTC000006 — Sunscreen Drug Products for OTC Human Use (avobenzone permitted up to 3%)
- EU Regulation (EC) No 1223/2009, Annex VI — Butyl Methoxydibenzoylmethane permitted as UV filter up to 5%
- Gholap A.D., Sayyad S.F., Hatvate N.T., et al. Drug Delivery Strategies for Avobenzone: A Case Study of Photostabilization. Pharmaceutics, 2023 (peak absorption ~357 nm; keto-enol tautomerism; photostabilization strategies)
- Avobenzone — overview (ScienceDirect): CTFA data submitted to FDA showing about a 36% loss of UV absorbance after ~1 hour of sun exposure when unstabilized
- Ginzburg A.L., Blackburn R.S., Santillan C., Truong L., Tanguay R.L., Hutchison J.E. Zinc oxide-induced changes to sunscreen ingredient efficacy and toxicity under UV irradiation. Photochemical & Photobiological Sciences, 2021 (DOI 10.1007/s43630-021-00101-2 — zinc oxide mixtures lower UVA protection and degrade organic filters under UV)
- Sayre R.M., Dowdy J.C., Gerwig A.J., Shields W.J., Lloyd R.V. Unexpected Photolysis of the Sunscreen Octinoxate in the Presence of the Sunscreen Avobenzone. Photochemistry and Photobiology, 2005;81(2):452-456 (DOI 10.1562/2004-02-12-RA-083.1 — concomitant photolysis of avobenzone and octinoxate)
- Ekstein S.F., Hylwa S. Sunscreens: A Review of UV Filters and Their Allergic Potential. Dermatitis, 2023 (DOI 10.1097/DER.0000000000000963 — oxybenzone is the most frequently reported contact/photocontact allergen among UV filters)
- DermNet — Allergy to avobenzone (most reactions arise from co-formulated photostabilizers; pure-avobenzone allergy rare)
This is not medical advice at all — cosmetic information only. Not suitable during pregnancy or breastfeeding; always consult your doctor.