Sh-Polypeptide-91: 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 Sh-Polypeptide-91?

Sh-Polypeptide-91 is a lab-designed fragment of hyaluronate synthase 3, the enzyme that naturally helps our skin make hyaluronic acid. Scientists produce it through controlled fermentation, then refine and stabilize the peptide so it can be blended into skincare formulas. Interest in this ingredient grew as researchers looked for gentler ways to prompt the skin to boost its own moisture levels, leading cosmetic chemists to adapt the biotech process for beauty products. Today Sh-Polypeptide-91 appears in lightweight serums, hydrating creams, sheet masks, eye treatments and targeted anti-aging blends where extra moisture and antioxidant support are welcome.

Sh-Polypeptide-91’s Cosmetic Benefits/Uses

This multitasking peptide supports skin health in several ways:

  • Antioxidant – helps neutralize daily environmental stressors, which can keep skin looking brighter and more even
  • Humectant – attracts water to the skin surface, giving a plumper, more hydrated feel without heaviness
  • Skin Conditioning – smooths and softens the outer layer so skin feels comfortable and looks refreshed

Who Can Use Sh-Polypeptide-91

Thanks to its lightweight, water-loving nature Sh-Polypeptide-91 suits nearly every skin type including dry, oily, combination and sensitive. It adds moisture without clogging pores so even acne-prone skin usually tolerates it well. People with extremely reactive skin should still scan the full ingredient list of the finished product to check for other triggers.

The peptide is produced by fermentation and refined in the lab, so no animal-derived material is involved. This makes it a vegan- and vegetarian-friendly option.

No data suggest that topical Sh-Polypeptide-91 poses a risk to pregnant or breastfeeding women, yet out of caution anyone who is expecting or nursing should show the product to a healthcare professional before adding it to a routine. This is not medical advice.

The ingredient does not make skin more sensitive to sunlight and can be worn day or night. It layers well with most common actives such as vitamin C, niacinamide or retinoids and is fragrance-free in its raw form, which further lowers the chance of irritation.

Potential Side Effects/Adverse Reactions

Responses to any skincare ingredient differ from person to person. The following list covers potential side effects connected to topical Sh-Polypeptide-91, but most users should not expect to run into these issues if the product is well formulated and used as directed.

  • Mild redness or warmth shortly after application
  • Temporary stinging on very dry or compromised skin
  • Itchiness or rash in those with a specific peptide allergy
  • Rare clogged pores if the finished formula contains heavy oils alongside the peptide

If any of these reactions occur stop using the product and consult a healthcare professional for guidance.

Comedogenic Rating

Rating: 0 (non comedogenic)

Sh-Polypeptide-91 is a small water soluble peptide so it does not form an occlusive film or leave heavy residue that could trap oil or dead cells inside pores. The molecule lacks fatty chains that typically raise comedogenic potential. It is usually blended into lightweight, fast absorbing bases which further lowers the chance of congestion. For these reasons people who are prone to acne and breakouts can generally use products containing Sh-Polypeptide-91 without added concern.

If a formula pairs the peptide with rich oils, waxes or heavy silicones the overall product may feel more occlusive, but this would be due to those other ingredients not the peptide itself.

Summary

Sh-Polypeptide-91 is a lab made fragment of hyaluronate synthase 3 that acts as an antioxidant, humectant and skin conditioner. It helps neutralize free radicals, draws moisture into the skin and smooths the surface for a refreshed look all while feeling weightless.

The peptide is still a niche addition so it is not as common as classics like hyaluronic acid or vitamin C, yet its multitasking benefits are making it steadily more popular in modern serums masks and eye creams.

Available safety data points to a very low risk of irritation, no known hormonal issues and no photosensitivity. Even so, patch testing a new product that contains Sh-Polypeptide-91 is always a smart way to make sure your skin agrees with the full formula.

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