Common Name(s): Oxothiazolidinecarboxylic acid,oxothiazolidinecarboxylic acid (otc),cysteine pro-drug,glutathione precursor anti-aging
CAS Number: N/a
DESCRIPTION
What It Does: Replenishes intracellular glutathione through sc-penetrant cysteine delivery โ the oxothiazolidine ring providing 10-20ร better sc penetration than free cysteine (which is oxidised on skin surface), enabling efficient intracellular gsh synthesis for anti-aging antioxidant protection.
Why It's Used: Otc solves the fundamental delivery limitation of cysteine โ the free thiol oxidises within minutes of skin contact to the sc-impermeant disulfide, while otc's stable ring form penetrates the sc and is cleaved intracellularly by 5-oxoprolinase releasing free cysteine for gsh synthesis.
How It Works: Otc 5-membered thiazolidine ring: stable at neutral ph, resistant to surface oxidation. intracellular 5-oxoprolinase cleaves the c-s bond releasing l-cysteine โ glutathione synthetase (gcl + gs) โ l-ฮณ-glutamylcysteinylglycine (gsh). intracellular gsh: peroxidase cofactor for hโoโ reduction; conjugation of electrophilic xenobiotics; maintenance of protein thiol redox state.
Typically Found In: Anti-aging,antioxidant,glutathione support
TECHNICAL DETAILS
Primary Category: Active ingredient โ 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: 0.1%โ3%
SOURCING & ETHICS
Vegan Status: Yes
Halal Status: Yes
Source Notes: Plant-derived extract or synthetic.
SKIN COMPATIBILITY
Irritancy Rating: 1/5 โ very low
Comedogenicity Rating: 0/5 โ 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
Glutathione decline with age: skin gsh decreases ~1-2% per year after age 20 โ the cumulative 60-80% decline by age 60 represents a primary driver of age-related oxidative stress accumulation. otc provides the most efficient topical route to intracellular cysteine for gsh replenishment.
Last Verified: 2026-03-22
Primary Sources: Cosing database,oxothiazolidinecarboxylic acid otc cysteine pro-drug glutathione review