Peptides

Bis-Sh-Decapeptide-9 Porphyra 334

INCI: BIS-SH-DECAPEPTIDE-9 PORPHYRA 334

Reviewed by Kate · Last updated 2 Jun 2026

Also known as: Bis-sh-decapeptide-9 Porphyra 334

A UV-protective peptide from marine algae that defends against photoaging and oxidative stress

Best For Skin Types

All, Sensitive, Mature

Addresses

Photoaging, Fine lines, Dryness, Sensitivity

Usage Frequency

Daily

What Is Bis-Sh-Decapeptide-9 Porphyra 334?

Bis-Sh-Decapeptide-9 Porphyra 334 is a mycosporine-like amino acid (MAA) extracted from Porphyra yezoensis, a species of edible red algae. In nature, these compounds help marine organisms survive intense UV exposure. The ingredient functions as both a UV filter and an antioxidant in skincare formulations, working to protect skin from environmental damage.

This peptide combines multiple protective mechanisms in a single ingredient, making it relevant for both prevention and treatment of sun-induced skin changes. It's typically used in concentrations suited to support overall skin resilience rather than replace dedicated sunscreen products.

Benefits for Your Skin

How It Works

The ingredient operates through two main pathways. First, its molecular structure absorbs UV radiation directly, converting light energy into harmless heat before it can damage skin cells. Second, it scavenges free radicals—unstable molecules created by sun exposure and pollution—preventing them from triggering inflammatory cascades and breaking down structural proteins.

In fibroblasts (the cells that produce collagen), research indicates it may suppress matrix metalloproteinase-1 (MMP-1), an enzyme responsible for collagen breakdown during photoaging. This dual action—preventing damage and supporting repair—positions it as a preventative anti-ageing agent rather than a treatment for existing damage.

Clinical Evidence & References

In vitro studies demonstrate that porphyra-334 scavenges reactive oxygen species, increases antioxidant enzyme activity, and reduces MMP-1 expression in skin cells. Research also shows it can suppress the production of advanced glycation end-products and promote collagen expression in fibroblast cultures. These findings suggest a protective effect against photoaging mechanisms.

Most evidence comes from laboratory and cell-based models rather than human clinical trials. Whilst the theoretical benefits are sound and supported by mechanistic research, long-term efficacy data in living skin remains limited. The ingredient appears well-tolerated, though large-scale safety and efficacy studies in diverse populations would strengthen the evidence base.

How to Use

This ingredient is typically found in serums, moisturisers, and targeted treatments rather than rinse-off products, allowing prolonged contact with skin. It works well in layered routines—apply after cleansing and toning, before heavier creams or oils. Combine with dedicated broad-spectrum sunscreen for complete photoprotection, as this ingredient complements rather than replaces SPF products. Use consistently as part of a morning or evening routine for best results.

Safety & Precautions

Bis-Sh-Decapeptide-9 Porphyra 334 is generally well-tolerated and not known to cause sensitisation or irritation. It is suitable for sensitive skin types, though as with any new product, a patch test is advisable before full application.

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