What Is Sh-Polypeptide-28?
Sh-Polypeptide-28 is a lab-crafted version of a human peptide that matches the protein sequence of prolactin. Scientists start by designing a gene identical to the one in our bodies then insert it into E. coli bacteria. During fermentation the bacteria read this gene and build the peptide chain, which can reach up to 227 amino acids and may form natural disulfide bonds or pick up simple sugar groups called glycosylations. After fermentation the peptide is purified, filtered and carefully dried to create a stable cosmetic ingredient.
Peptides first caught the beauty industry’s attention in the 1990s for their ability to signal skin and hair cells. As production methods improved chemists learned they could recreate complex human proteins safely through biotechnology, opening the door for ingredients like Sh-Polypeptide-28. Today it appears in leave-on hair treatments, strengthening masks, scalp serums and premium conditioners where brands look for high-performance actives that support healthy-looking hair.
Sh-Polypeptide-28’s Cosmetic Benefits/Uses
In personal care formulas Sh-Polypeptide-28 plays one key role.
Hair conditioning: This peptide can bind to the hair shaft helping smooth the cuticle, reduce static and improve manageability. By supporting a healthier surface it leaves strands feeling softer and looking shinier which is especially helpful for damaged or chemically treated hair.
Who Can Use Sh-Polypeptide-28
Because Sh-Polypeptide-28 is a lightweight conditioning peptide it is gentle enough for all scalp and hair types including oily, dry, color treated and chemically processed strands. It does not clog pores or add heavy residue so even those with sensitive or breakout-prone scalps can usually use it without trouble.
The peptide is made by fermenting bacteria and is not taken from animals so formulas that use it are generally suitable for vegans and vegetarians. Always check the full ingredient list though as other components in a finished product might not meet the same standard.
No research shows that topical Sh-Polypeptide-28 poses a risk to women who are pregnant or breastfeeding. Absorption through the skin is expected to be minimal yet this is not medical advice and anyone who is expecting or nursing should still ask a doctor before adding new products to a routine.
The ingredient does not increase photosensitivity so it will not make skin or scalp more prone to sunburn. It also plays nicely with most common hair care actives including proteins silicones and mild acids.
Potential Side Effects/Adverse Reactions
Reactions to Sh-Polypeptide-28 vary from person to person. The points below outline potential side effects but most users will not notice any problems when the ingredient is formulated and used correctly.
- Minor scalp redness or itching
- Mild burning or tingling right after application
- Rare allergic contact dermatitis
- Eye irritation if rinsed or rubbed into the eyes
If any of these reactions occur stop using the product and consult a healthcare professional if symptoms persist or worsen.
Comedogenic Rating
Rating: 0 / 5 (non-comedogenic)
Sh-Polypeptide-28 is a large, water-soluble protein that sits on the surface of hair strands rather than penetrating deeply into skin follicles. Its molecular size and solubility mean it does not trap oil or debris, which are the main factors that encourage clogged pores. Because of this profile it is considered safe for acne-prone or breakout-prone users.
As a fermented, highly purified peptide it typically appears at low concentrations in finished formulas, further lowering any pore-clogging risk.
Summary
Sh-Polypeptide-28 is a bio-engineered version of the human prolactin peptide used in cosmetics for one standout purpose: hair conditioning. By lightly coating the hair shaft it smooths the cuticle, reduces static and boosts softness and shine, particularly in damaged or chemically treated hair.
While not yet a household name, it is gaining traction in high-end leave-on treatments and scalp serums where brands seek science-backed actives that differentiate their products.
Current data suggests the ingredient is well tolerated for most users with minimal risk of irritation or sensitization. As with any new cosmetic, patch testing a small area first is a smart way to ensure personal compatibility before full use.