Cysteine/Oligomeric Proanthocyanidin
INCI: CYSTEINE/OLIGOMERIC PROANTHOCYANIDIN
Reviewed by Daisy · Last updated 14 Aug 2026
A protein-derived conditioning agent that supports skin's natural resilience
Best For Skin Types
All, Dry, Sensitive, Mature
Addresses
Usage Frequency
Daily
What Is Cysteine/Oligomeric Proanthocyanidin?
Cysteine is a semi-essential amino acid, whilst oligomeric proanthocyanidins (OPCs) are plant-derived polyphenols found in sources such as grape seed and pine bark. When combined in a cosmetic formulation, this pairing functions primarily as a skin conditioner, working to improve the texture and feel of the skin surface.
The cysteine component contributes to the structure of keratin and collagen in the skin, whilst the proanthocyanidins are recognised for their antioxidant properties. Together, they aim to support the skin's natural barrier function and overall conditioning.
How It Works
Cysteine acts as a building block for the skin's structural proteins, particularly keratin and collagen. By providing this amino acid, formulations can support the skin's inherent ability to maintain firmness and elasticity.
The oligomeric proanthocyanidins work through their antioxidant mechanism, binding to free radicals and reducing oxidative stress within skin cells. This may help protect the skin from environmental damage and support the skin's natural repair processes.
Clinical Evidence & References
Research on cysteine in skincare is limited, though the amino acid is known to play a structural role in skin proteins. Some evidence suggests topical amino acid delivery can support skin conditioning, though results vary depending on formulation and concentration.
Proanthocyanidins have been studied for their antioxidant potential, with some research indicating benefit in protecting skin from UV-induced damage. However, evidence for specific cosmetic outcomes remains modest, and more research is needed to establish efficacy thresholds in skincare products.
How to Use
This ingredient is typically found in serums, moisturisers and conditioning treatments. Apply to clean skin as part of your regular routine. Since it functions as a conditioning agent, layering with other actives (such as vitamin C or niacinamide) is generally compatible, though it is always wise to introduce new products gradually.
Safety & Precautions
Frequently Asked Questions
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