Sh-Oligopeptide-91 Sp: 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-Oligopeptide-91 Sp?

Sh-Oligopeptide-91 Sp is a lab-made fragment of a naturally occurring human protein called ARS Interacting Multi-Functional Protein 1. Scientists reproduce just 15 of its 312 amino acids to create a small, stable peptide that is easy to work with in skincare formulas. Because it is synthesized entirely in the lab, no animal or plant sources are involved, making it a vegan-friendly ingredient with consistent purity from batch to batch. Production starts with automated peptide synthesis, where each of the 15 amino acids is linked in the precise order dictated by the original human protein. After assembly, the chain is purified, tested for identity and strength then blended into a cosmetic-grade powder or solution.

The interest in this peptide for cosmetics began when researchers noticed certain fragments of larger proteins could interrupt steps in the skin’s pigment-production pathway. Over the past decade formulators have explored these mini proteins as gentler alternatives to older brightening agents like hydroquinone. Today you can spot Sh-Oligopeptide-91 Sp in leave-on serums, spot correctors, brightening masks and all-over facial lotions aimed at evening skin tone.

Sh-Oligopeptide-91 Sp’s Cosmetic Benefits/Uses

In topical products this peptide serves one main purpose: bleaching. By interfering with the biochemical signals that lead skin cells to make melanin it helps fade the look of existing dark spots and discourages new discoloration. When used consistently in a well-formulated product it can promote a clearer, more uniform complexion while being milder than many traditional lightening agents.

Who Can Use Sh-Oligopeptide-91 Sp

This peptide is generally suitable for all skin types, including dry, normal, combination and oily skin, because it is lightweight and non-occlusive. Sensitive or barrier-impaired skin can also tolerate it in most cases, yet very reactive complexions should introduce it gradually and look for formulas free of added fragrance or strong exfoliating acids.

Because the ingredient is produced entirely through synthetic peptide technology with no animal or plant derivatives, it is appropriate for vegans and vegetarians who wish to avoid animal-derived components in their skincare routines.

There is no specific research suggesting harm to pregnant or breastfeeding women when the peptide is applied topically. Still, safety data during pregnancy and lactation is limited, so this information is not medical advice and anyone who is expecting or nursing should confirm product use with a qualified healthcare professional.

Sh-Oligopeptide-91 Sp is not known to induce photosensitivity, so it will not make skin more prone to sunburn. Daily sunscreen is still recommended to protect fading dark spots from returning, but the peptide itself does not boost UV sensitivity.

Potential Side Effects/Adverse Reactions

Responses to topical Sh-Oligopeptide-91 Sp differ from person to person. The points below list potential side effects, yet most users will not encounter them when the ingredient is properly formulated and used as directed.

• Mild redness or warmth at the application site

• Temporary stinging or tingling during the first few uses

• Dryness or slight flaking if layered with strong exfoliants

• Localized allergic reaction such as itching, swelling or small hives

• Interaction irritation when combined with high-strength retinoids or chemical peels

If any of these effects occur discontinue use and consult a healthcare professional if symptoms persist or worsen.

Comedogenic Rating

Rating: 0 / 5 – Sh-Oligopeptide-91 Sp is a tiny water-soluble peptide that does not contain heavy oils, waxes or fatty acids that can clog pores. It stays on the skin surface long enough to do its brightening job then is either absorbed or rinsed away without leaving an occlusive film. Because it is produced in a pure lab setting contaminants that might block pores are also unlikely.

Suitable for acne-prone or breakout-prone skin.

Keep in mind that the finished product formula matters too. If the peptide sits inside a rich cream packed with butters the overall product could still feel heavy even though the peptide itself is pore-friendly.

Summary

Sh-Oligopeptide-91 Sp is a lab-synthesized 15-amino-acid fragment that targets uneven skin tone by calming the signals that trigger excess melanin. In skincare it is prized for gentle bleaching action that can fade dark spots and help stop new ones from forming, all while being kinder to skin than harsh lighteners like hydroquinone.

It is not a headline ingredient yet, showing up mainly in niche brightening serums and spot correctors rather than mass-market lines, but interest is growing as consumers look for peptide-based alternatives to older actives.

Current data points to a high safety margin with low irritation risk. As with any new cosmetic, patch test a small area first to make sure your skin agrees with the full formula before applying it all over.

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