What Is Rh-Polypeptide-18?
Rh-Polypeptide-18 is a lab made version of a human peptide that comes from the Interleukin-1 Beta gene. Scientists copy the gene from human cells and insert it into harmless E. coli bacteria, which then act like tiny factories and ferment the peptide in large tanks. After fermentation the peptide is purified, checked for quality and readied for use in skincare and hair care formulas.
Chemically, it is a single chain of up to 269 amino acids that may form natural disulfide bonds or pick up light glycosylation during production. In simpler terms, it is a string of the same building blocks found in our own skin and hair proteins, so the body recognizes it and tolerates it well.
Peptides first caught the beauty world’s eye in the late 1990s for their ability to signal skin repair. As biotech methods improved, brands began turning to recombinant peptides like Rh-Polypeptide-18 because they are consistent, vegan friendly and can be produced on a large scale without using animal sources. Today you will spot this ingredient in leave-on hair conditioners, anti-aging serums, calming face creams, sheet masks, scalp treatments and specialty eye products.
Rh-Polypeptide-18’s Cosmetic Benefits/Uses
Below are the main ways Rh-Polypeptide-18 can improve a beauty formula
- Hair conditioning: The peptide can bind lightly to the hair shaft, helping smooth cuticles, reduce frizz and add a soft feel without weight or grease
- Skin conditioning: On skin it supports a hydrated barrier, soothes temporary redness and leaves the surface feeling silky and supple
Who Can Use Rh-Polypeptide-18
Rh-Polypeptide-18 is generally suitable for all skin and hair types, including dry, sensitive, mature and oily skin. Its lightweight, non-occlusive nature means it does not clog pores or leave a heavy residue, so acne-prone users can usually tolerate it well. As it is free of fragrance and common irritants, those with easily upset skin often find it calming rather than aggravating.
The peptide is produced entirely through microbial fermentation without animal-derived raw materials, making it appropriate for vegans and vegetarians.
No data currently suggest that topical Rh-Polypeptide-18 poses a risk to women who are pregnant or breastfeeding. That said this is not medical advice and anyone who is expecting or nursing should run any new skincare or hair care product past a qualified doctor just to be safe.
The ingredient does not absorb ultraviolet light or alter the skin’s normal response to sun, so it is not associated with photosensitivity. It also plays well with most other common actives such as niacinamide, hyaluronic acid and mild exfoliating acids.
Potential Side Effects/Adverse Reactions
Side effects from topical Rh-Polypeptide-18 vary from person to person. The following list covers potential reactions, yet these are unlikely to occur for the average user when the ingredient is properly formulated and preservative-protected.
- Mild transient redness or warmth immediately after application
- Temporary itching or tingling in very sensitive skin
- Rare allergic contact dermatitis in individuals already allergic to certain peptides or fermentation residues
- Stinging if applied to broken or freshly exfoliated skin
If you experience any persistent or worsening irritation stop using the product and seek advice from a healthcare professional.
Comedogenic Rating
Rating: 0 / 5
Rh-Polypeptide-18 is a large, water-soluble peptide that sits on the skin surface without blocking pores or mixing with sebum, so it earns a solid zero on the comedogenic scale. It has no oily or waxy components and is typically used at low percentages, which further reduces any clogging risk. This makes the ingredient friendly for people who are prone to acne or breakouts. The only caveat is that the overall formula counts; if a cream containing the peptide is loaded with heavy butters or comedogenic oils, the finished product could still cause congestion.
Summary
Rh-Polypeptide-18 is a lab-crafted version of a human peptide originally linked to Interleukin-1 Beta. In hair care it lightly binds to the strand, smoothing cuticles for softer, less frizzy hair. On skin it supports barrier hydration, calms temporary redness and leaves a silky after-feel, all while remaining virtually weightless and vegan friendly.
Although not yet a household name, this biotech peptide is gaining traction in premium serums, eye creams and scalp treatments thanks to its reliable performance and clean production method. Most users tolerate it very well, with side effects being rare and mild. Still, everyone’s skin is different, so it is wise to patch test any new product that features Rh-Polypeptide-18 before applying it more broadly.