Acetyl S-Silkworm Oligopeptide-1 Sp Amide: 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 23, 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 Acetyl S-Silkworm Oligopeptide-1 Sp Amide?

Acetyl S-Silkworm Oligopeptide-1 Sp Amide is a modified protein fragment that comes from silkworm silk. Scientists take a short chain of amino acids found in silk, change the N-terminus into an amide, then add an acetyl group to improve stability and skin affinity. The result is a lightweight peptide that blends smoothly into water-based or emulsion formulas.

The idea of using silk in beauty care dates back centuries because silk threads were known to leave hands soft after weaving. Modern labs isolated the helpful peptides in silk during the 1990s, and further tweaks like acetylation made them more effective and less prone to breaking down in a jar. Today this ingredient is produced by fermenting safe strains of bacteria that create the silkworm-identical peptide, which is then purified and chemically acetylated under mild conditions.

You will mainly spot Acetyl S-Silkworm Oligopeptide-1 Sp Amide in lightweight serums, oil-control moisturizers, sheet masks, soothing gels, and multi-tasking anti-aging creams. Its gentle nature also makes it a popular pick for leave-on treatments aimed at combination or sensitive skin.

Acetyl S-Silkworm Oligopeptide-1 Sp Amide’s Cosmetic Benefits/Uses

This peptide pulls double duty by caring for the skin surface while helping keep excess oil in check. Key benefits include:

  • Anti-Sebum: Helps regulate surface oil so skin looks fresh longer and makeup stays put
  • Skin Conditioning: Supports a smooth hydrated feel that can soften fine lines and rough patches
  • Emollient: Adds a light silky layer that reduces moisture loss without clogging pores
  • Skin Protecting: Forms a breathable film that shields against daily pollutants and minor irritants

Who Can Use Acetyl S-Silkworm Oligopeptide-1 Sp Amide

This peptide suits most skin types. Its oil balancing nature makes it a natural fit for oily and combination skin while the light emollient effect offers extra slip for normal and mildly dry skin. Extremely dry or eczema-prone skin may still benefit but will usually need a richer occlusive cream on top to lock moisture in.

Although the ingredient is inspired by silkworm silk it is produced through microbial fermentation with no animal-derived raw material so it is considered suitable for vegans and vegetarians. Those avoiding any insect related references for ethical or cultural reasons should read labels carefully but no animal parts are present.

The molecule is not known to penetrate deeply or enter the bloodstream in measurable amounts so it is generally viewed as low risk for pregnant or breastfeeding women. This is not medical advice and anyone expecting or nursing should clear all skincare choices with their health professional first just to be safe.

Acetyl S-Silkworm Oligopeptide-1 Sp Amide does not increase photosensitivity and can be worn day or night. It also layers well with acids retinoids vitamin C and common sunscreen filters without degrading them.

Potential Side Effects/Adverse Reactions

Reactions to topical Acetyl S-Silkworm Oligopeptide-1 Sp Amide differ from person to person. The following are potential side effects only and in well formulated products most users will not notice any issues.

  • Mild transient redness or warmth right after application
  • Light itching or tingling in sensitive individuals
  • Rare allergic contact dermatitis resulting in rash or swelling
  • Occasional clogged pores or small breakouts in very acne-prone skin if combined with heavy occlusives

If any persistent discomfort swelling or rash occurs stop using the product and consult a qualified healthcare professional.

Comedogenic Rating

Rating: 1/5. Acetyl S-Silkworm Oligopeptide-1 Sp Amide is a small water-soluble peptide that lays down only a thin breathable film and contains no heavy oils or waxes, so it shows very little tendency to clog pores. Most formulations that use it are lightweight serums or gels further lowering any occlusive risk.

In practical terms it is generally fine for acne-prone or breakout-prone skin. Only when paired with thick butters or poorly chosen occlusives could it contribute to congestion.

Because the ingredient helps regulate surface sebum it may even improve an oily complexion when used in well balanced formulas.

Summary

Acetyl S-Silkworm Oligopeptide-1 Sp Amide acts as an anti-sebum agent skin conditioner emollient and protective film former. Its acetylated amide structure boosts stability and affinity so it can sit on the skin surface where it lightly binds water smooths texture tempers excess oil and creates a soft barrier against irritants.

The peptide is still a niche addition compared with headline actives like hyaluronic acid or niacinamide but is slowly gaining traction in K-beauty style serums and oil-control moisturizers thanks to its silky feel and gentle oil balancing effect.

Current safety data labels it low risk with minimal irritation potential for most users. Even so it is smart to patch test any new product containing this peptide to rule out individual sensitivities and enjoy its benefits with confidence.

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