Undecylenoyl Phenylalanine
A synthetic brightening active. The maker links it to evening skin tone and working on dark spots; independent data are limited. Well tolerated.
Evidence by route
Topical application
A brightening active. Safe; independent data limited.
- CIR Cosmetic Ingredient Review safety assessment
How to read tiers A–F
- BLimited evidence. One RCT or several controlled studies with limitations
Tolerability and safety
- Irritation potential
- Low
- Allergen risk
- Low
- Pregnancy
- Safe
- Suitable for
- Normal, Dry, Combination, Oily, Sensitive
About this ingredient
Undecylenoyl Phenylalanine is a synthetic active that combines undecylenic acid with the amino acid phenylalanine. It goes into depigmenting formulas with the idea of interfering with the signalling that stimulates melanocytes, which would help even out tone and fade dark spots. On efficacy a caveat is needed. Some brand studies point to improved tone, but independent data are limited. It is a supporting brightening active: reasonable within a routine, useful as a complement to other better-documented brighteners, not a replacement for them. Results, when they come, are gradual. For topical use it is not meaningfully absorbed, so it can be used during pregnancy and breastfeeding without restriction, unlike more problematic brighteners such as hydroquinone. It is well tolerated: irritation and allergy potential are low, with no comedogenicity rating. It suits sensitive skin. As with any spot treatment, it is best paired with daily sun protection so you do not lose the gains.
Frequently asked questions
Is Undecylenoyl Phenylalanine safe during pregnancy?
Undecylenoyl Phenylalanine is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
What skin types is Undecylenoyl Phenylalanine for?
Undecylenoyl Phenylalanine suits: normal, dry, combination, oily, sensitive.
What is Undecylenoyl Phenylalanine and what does it do in cosmetics?
A synthetic brightening active.
What's the INCI name for Undecylenoyl Phenylalanine?
The INCI name is Undecylenoyl Phenylalanine. It may also appear as: Sepiwhite.
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