Sh-Polypeptide-34: 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-34?

Sh-Polypeptide-34 is a lab made version of a tiny protein that naturally occurs in the body. Scientists create it by inserting a man-made copy of the human gene for interleukin 13 into friendly strains of E. coli. These bacteria act like miniature factories, churning out the peptide during a controlled fermentation process. After the peptide is harvested it is carefully purified, resulting in a single-chain protein of up to 146 amino acids that may include a few stabilizing disulfide links or sugar side groups. Because the finished material mirrors the building blocks found in skin it fits smoothly into cosmetic formulas.

The idea of borrowing messenger proteins for beauty products took off in the early 2000s when peptide technology became more affordable. Sh-Polypeptide-34 entered the market as brands looked for gentle ways to boost skin comfort and resilience. Today you will spot it in leave-on moisturizers, soothing serums, anti-aging creams, sheet masks and targeted treatments sold for post-procedure care.

Sh-Polypeptide-34’s Cosmetic Benefits/Uses

This peptide is prized for one key role in skincare.

As a skin conditioning agent Sh-Polypeptide-34 helps the surface of the skin feel softer smoother and healthier. It supports the natural barrier so moisture stays in longer and the complexion looks calm and refreshed, which makes it a useful addition to daily hydrators and recovery products.

Who Can Use Sh-Polypeptide-34

Sh-Polypeptide-34 is generally friendly to all skin types. Dry skin appreciates the added conditioning fresh breakouts are not provoked and sensitive complexions tend to tolerate it well because the peptide is modeled after a natural body signal. There are no known reasons for people with oily or combination skin to avoid it either.

The peptide is produced in a lab using bacteria so no animal material is involved. That makes it suitable for vegans and vegetarians.

No data suggests a risk for women who are pregnant or breastfeeding when the ingredient is used in a topical cosmetic product. This is not medical advice and anyone expecting or nursing should check with their doctor before adding new skincare just to be safe.

Sh-Polypeptide-34 does not cause photosensitivity. You can apply it morning or night without worrying that it will make your skin more prone to sunburn.

Potential Side Effects/Adverse Reactions

Reactions to topical Sh-Polypeptide-34 vary from person to person. The effects listed below are possible but most users will never notice them if the product has been made correctly and is used as directed.

  • Mild redness or warmth at the application site
  • Temporary itching or tingling
  • Rare allergic contact dermatitis in people sensitive to fermentation-derived proteins

If you experience any of the above discontinue use and consult a healthcare professional.

Comedogenic Rating

Rating: 0 / 5

Sh-Polypeptide-34 is a large water-soluble protein that has no oily or waxy parts so it cannot block pores. It usually sits on the skin surface or is rinsed away during cleansing which keeps it from building up inside follicles. Because of this it scores a clear zero on the comedogenic scale.

That makes the peptide a safe pick for people who deal with acne or frequent breakouts.

If the finished product also contains heavy oils or rich butters the overall formula could still be pore-clogging so check the full ingredient list if you are very breakout prone.

Summary

Sh-Polypeptide-34 is a lab grown copy of a human signaling protein that serves one main purpose in cosmetics: skin conditioning. It supports the skin barrier so water stays in cells longer and the surface feels smooth calm and healthy. By matching the amino acid pattern found in our own bodies the peptide slips into formulas without causing stress to most complexions.

While not as famous as collagen peptides or well-known actives like vitamin C it has a small loyal following in soothing serums and post-treatment creams. Brands that focus on gentle barrier care pick it for its light feel and low risk profile.

Overall safety is high with only rare reports of mild irritation. As with any new skincare ingredient it is smart to patch test a product that contains Sh-Polypeptide-34 before using it on your whole face especially if your skin is sensitive.

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