Common Name(s): Hydroxytryptophan,hydroxytryptophan (5-htp),serotonin precursor,mood-skin neurocosmetic active
CAS Number: N/a
DESCRIPTION
What It Does: Provides skin serotonin pathway support through 5-htp precursor delivery to skin neurons, delivering neurocosmetic calming activity through dermal serotonin modulation and antioxidant protection from the tryptophan indole chromophore.
Why It's Used: Skin is an active serotonin-synthesising organ — skin cells express tryptophan hydroxylase and aromatic amino acid decarboxylase for local serotonin synthesis. topical 5-htp supplementation supports this pathway for anti-stress skin calming from the local serotonin axis.
How It Works: 5-htp → aromatic amino acid decarboxylase (aaad) → serotonin (5-ht) in skin cells. serotonin in skin: 5-ht2a receptor on keratinocytes → pi3k → proliferation/differentiation balance; 5-ht1a on sensory neurons → camp → reduced substance p release → anti-inflammatory calming. the indole chromophore provides radical scavenging from n-h donation.
Typically Found In: Neurocosmetics,anti-stress skin care,anti-inflammatory
TECHNICAL DETAILS
Primary Category: Active ingredient – antioxidant
Secondary Functions: Free radical scavenging,anti-aging
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 0.01%–1%
SOURCING & ETHICS
Vegan Status: Yes
Halal Status: Yes
Source Notes: Plant-derived extract or synthetic.
SKIN COMPATIBILITY
Irritancy Rating: 1/5 – very low
Comedogenicity Rating: 0/5 – non-comedogenic
Sensitivity Concerns: Non-irritating; well-tolerated.
Safe for Sensitive Skin: Yes
SAFETY & COMPATIBILITY
Safety Profile: Excellent safety profile. ewg score: 1.
Works Well With: Vitamin c,vitamin e,ferulic acid,spf,other antioxidants
Avoid Combining With: No significant incompatibilities
SCIENTIFIC NOTE
5-htp blood-brain barrier concern: oral 5-htp crosses the bbb causing significant cns serotonin increase — topical application is limited to skin serotonin pathway modulation with minimal systemic exposure, providing the neurocosmetic calming without central serotonergic effects.
Last Verified: 2026-03-22
Primary Sources: Cosing database,5-hydroxytryptophan serotonin neurocosmetics anti-stress review