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Moumoujus

PHENYLALANINE.

Valuable CAS 63-91-2 / 150-30-1 / FRAGRANCE, HAIR CONDITIONING, SKIN CONDITIONING

Phenylalanine is an essential amino acid recognized for its multifaceted role in skin health. While it serves as a precursor for melanin, its derivative, Undecylenoyl Phenylalanine, is a precision ingredient effectively used to address various forms of hyperpigmentation. Beyond pigment regulation, it contributes to overall skin conditioning, hydration, and protection.

Summary

Skin conditioning Humectant Antioxidant Skin brightening Collagen boosting Soothing

Science

Mechanism of Action

Phenylalanine, an essential amino acid, serves as a direct precursor to melanin, the skin's primary pigment. Its derivative, Undecylenoyl Phenylalanine, precisely targets melanin production by acting as an alpha-melanocyte-stimulating hormone (MSH) antagonist. This action hinders MSH binding to its receptor (MC1R) on melanocytes, effectively stopping the melanin creation process. Additionally, phenylalanine itself helps the skin retain moisture, contributing to a more hydrated appearance, and plays a role in maintaining the skin's natural barrier. It is also involved in boosting collagen production for firmer skin, provides antioxidant protection against environmental damage, and possesses soothing properties.

Research

Clinical Evidence

High confidence
Effective range 1–2%
Optimal

1-2% for its derivative, Undecylenoyl Phenylalanine, for hyperpigmentation treatment.

Key findings

  1. 01 A 2% concentration of Undecylenoyl Phenylalanine was found effective in treating age spots (solar lentigines) and melasma.
  2. 02 A combination of 1% Undecylenoyl Phenylalanine with 5% Niacinamide demonstrated superior efficacy in reducing facial hyperpigmentation compared to niacinamide alone.
  3. 03 Topical L-phenylalanine, when combined with UVA light, appears to improve symptoms of vitiligo (concentration not specified in study).

Transparency

Dusting Analysis

Not commonly dusted

Insufficient data in research to determine specific dusting thresholds or common dusting practices for Phenylalanine.

The Formula

Formulation

Solubility
Water (for Phenylalanine itself); its derivative, Undecylenoyl Phenylalanine, is oil-soluble.
Optimal pH N/A
0 7 14

Stability

Phenylalanine is generally water-soluble. L-Phenylalanine may be light-sensitive and acts as a weak acid in solution. No specific optimal pH range for Phenylalanine itself was explicitly found, though a study on its derivative was conducted at pH 5.8.

Synergies

  • Niacinamide (when combined with Undecylenoyl Phenylalanine for enhanced hyperpigmentation reduction)
  • UVA light (when combined with L-phenylalanine for vitiligo treatment)

Safety

Safety Profile

CIR Status
Safe as used
Max tested
0.3%
Sensitization risk Low

The CIR Expert Panel concluded that amino acids, including phenylalanine, are safe for use in cosmetics, with typical cosmetic concentrations (0.00009–0.3%) deemed low enough to prevent significant exposure. The FDA also recognizes amino acids as direct food additives. While consumption is dangerous for individuals with phenylketonuria (PKU), topical cosmetic use is generally considered safe, with patch testing recommended for sensitive skin.

Your Skin

Skin Compatibility

Yes Normal
Yes Dry
Yes Oily
Yes Sensitive
Irritancy Low
Comedogenicity Unknown

Our Assessment

Verdict

Valuable

Phenylalanine and its derivatives offer multifaceted benefits, from potent skin brightening and hydration to supporting skin barrier integrity across all skin types.

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