sh-Polypeptide-12 is a synthetic recombinant single-chain peptide, an analog of human Interleukin 4 (IL-4), that acts as an antihistamine or immune-suppressor agent to reduce scratching by inhibiting the autoimmune response. It is known under the trade name CG-IL-4; the former INCI designation was Human Oligopeptide-15 (rh-Oligopeptide-15).
sh-Polypeptide-12 lessens skin irritation on the lower part of the legs, which is generally related to circulatory problems. It is effective against psoriasis, an autoimmune condition in which the immune system produces too many immune cells. IL-4 treatment decreases PASI (Psoriasis Area and Severity Index).
In vivo studies showed that sh-Polypeptide-12 activates and induces the proliferation of dermal fibroblasts, enhances the production of GAGs, collagen, and decorin, and accelerates wound healing. Targeted therapies with rh-IL-4 showed promising results in reducing chronic dermal inflammation.
Studies have shown that IL-4 can reduce the production of filaggrin, loricrin, and involucrin, which are involved in skin hydration and barrier function, via the IL-4Rα signaling pathway, a pattern typical of Atopic Dermatitis. Thus, individuals prone to Atopic Dermatitis should use skincare products containing sh-Polypeptide-12 (IL-4-mimetic) with caution and consult a physician if they experience adverse reactions or changes in skin condition.
