Serralysin: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: June 30, 2025
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We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Serralysin?

Serralysin is a protein-digesting enzyme produced during the fermentation of the bacterium Serratia marcescens. Although this microbe was first noted in medical research, cosmetic chemists later discovered that the enzyme it releases could soften skin and improve product texture. Modern production starts with a controlled fermentation of the bacteria in large stainless-steel tanks. After the enzyme forms, it is separated, purified and stabilized so it stays active when blended into creams or serums.

Because serralysin is water-soluble and works well at skin temperature, formulators add it to a range of topical products. You will most often see it in sheet masks, gentle exfoliating gels, firming eye treatments, anti-aging lotions and post-procedure soothing creams. Its popularity keeps growing as brands look for milder alternatives to grainy scrubs or strong acids.

Serralysin’s Cosmetic Benefits/Uses

In skin care serralysin offers two main functions that make a formula feel better and work harder for the user.

  • Skin Conditioning: By breaking down dead surface proteins the enzyme helps clear dull debris so fresh skin can show through. This leaves the complexion feeling smoother and looking brighter while also helping other actives absorb more easily.
  • Emollient: Serralysin has a softening effect that can reduce rough patches and boost overall suppleness. When paired with moisturizers it helps lock in hydration giving a velvety after-feel without greasiness.

Who Can Use Serralysin

Serralysin suits most skin types including normal, dry, oily and combination because it works gently at the surface rather than stripping oils. People with very reactive or broken skin should proceed with caution because any active enzyme can heighten sensitivity in compromised barriers.

The ingredient is produced through bacterial fermentation with no animal tissues, so it is generally considered suitable for vegans and vegetarians. Some manufacturers may grow the bacteria on nutrient media that contain dairy or other animal by-products, so strict vegans may want to confirm sourcing with the brand.

Current data shows no specific risks for women who are pregnant or breastfeeding when serralysin is used in topical cosmetics. The enzyme does not penetrate deeply or enter the bloodstream in meaningful amounts. That said, this is not medical advice and anyone who is pregnant or nursing should review new skin care with a qualified health professional.

Serralysin does not make skin more prone to sun damage and has no known effect on photosensitivity. It layers well with most common actives such as niacinamide, ceramides and gentle fruit acids, which makes it easy to fit into existing routines.

Potential Side Effects/Adverse Reactions

Side effects from topical serralysin differ from person to person. The points below outline potential reactions though most users will not experience them if the product has been formulated and stored correctly.

  • Redness or mild stinging in people with very sensitive skin
  • Localized itching if the enzyme stays on the skin longer than directed
  • Dry patches when used too often without enough moisturizer
  • Allergic response such as swelling or hives in rare cases of protein allergy
  • Interaction with open wounds leading to increased irritation if applied on broken skin

If any of these effects occur stop using the product immediately and seek medical guidance if symptoms persist or worsen.

Comedogenic Rating

Comedogenic rating: 0 out of 5.

Serralysin is a water based enzyme with no oils or waxes so it will not clog pores. It dissolves loose surface proteins rather than collecting inside follicles and there are no reports of it sparking blackheads or whiteheads.

This makes it appropriate for people who are prone to acne or breakouts.

If a product combines serralysin with heavy butters or thick silicones the overall formula could still feel pore blocking. Always scan the full ingredient list when congestion is a worry.

Summary

Serralysin acts as a skin conditioning and emollient ingredient. It breaks down dead protein buildup to reveal a smoother brighter layer underneath while leaving a soft hydrated feel.

The enzyme is popping up more often in sheet masks eye creams and mild peel gels yet it remains a niche addition compared with staples like glycolic acid or niacinamide.

Topical use is generally safe with only mild irritation risks for very sensitive skin. Even so it pays to patch test any new product that features serralysin before adding it to your routine.

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