What Is sh‑Polypeptide‑7 and Why Is It Used in Some Advanced Hair Serums and Treatments?

In recent years, many premium hair serums and scalp treatments have introduced an ingredient called sh‑Polypeptide‑7, which marketing often presents as a cutting‑edge peptide for hair growth and scalp regeneration. When we first encounter such claims, the natural question is whether this ingredient is supported by real scientific evidence or whether it belongs more to the realm of cosmetic marketing language. To understand why sh‑Polypeptide‑7 appears in these formulations, we must examine what it is at a molecular level, how it is supposed to work, and what current research actually confirms or fails to confirm.

sh‑Polypeptide‑7 is the cosmetic ingredient (INCI) name for recombinant human somatotropin — that is, human growth hormone itself, not a small fragment of it. The EU cosmetic-ingredient database (CosIng) describes it as a single-chain recombinant human peptide made by fermentation in E. coli from a synthesized copy of the human somatotropin gene, of up to 217 amino acids. The “sh” prefix means “synthetic human”: the protein is not extracted from human tissue but made by bacteria that carry the human gene. At this size it is a full protein hormone rather than a short peptide.

Proteins control many biological processes, including cell growth, repair, and signaling between tissues. Because peptides can imitate certain biological signals, cosmetic science has increasingly explored them as ingredients in skin and hair products.

The connection between sh‑Polypeptide‑7 and hair health stems from the biological role of human growth hormone. Growth hormone influences cell regeneration and stimulates the release of insulin‑like growth factor‑1, often called IGF‑1. IGF‑1 plays an important role in tissue repair and has been shown in laboratory research to affect hair follicle activity. Hair follicles are small organs embedded in the scalp that cycle through phases of growth, rest, and shedding. Their function depends heavily on specialized cells known as dermal papilla cells, which regulate hair fiber production by sending chemical signals to surrounding cells. Growth factors such as IGF‑1 and fibroblast growth factors have been shown in experimental settings to stimulate these cells and encourage the growth phase of the hair cycle.

Manufacturers of cosmetic products containing sh‑Polypeptide‑7 suggest that this peptide can imitate some of the signaling effects of natural growth hormone, thereby supporting the scalp environment and potentially encouraging healthier hair follicles. These are the manufacturers' claims; they have not been tested in a published human trial.

In controlled laboratory conditions, various peptides and growth factor fragments have demonstrated the ability to influence cell behavior. However, there is a significant difference between observing molecular activity in cells grown in a laboratory dish and achieving meaningful biological effects when a substance is applied to the human scalp.

One of the major scientific concerns is penetration. The outer layer of the skin, known as the stratum corneum, acts as a protective barrier that prevents most large molecules from entering deeper tissues. Peptides, depending on their size and chemical properties, often struggle to pass through this barrier in significant amounts. Large proteins usually cross intact skin poorly, but this has not been measured for sh‑Polypeptide‑7. It is not known whether it reaches the hair follicle cells where it would need to act. Some clinics apply products containing it after microneedling, laser or exfoliation, which bypasses the skin barrier; no published study describes the effects or the safety of a recombinant growth hormone applied this way. Ask a doctor before applying any product to microneedled or lasered skin.

When we examine the research literature directly, we find that there are currently no high‑quality clinical trials that specifically investigate sh‑Polypeptide‑7 as a topical treatment for hair growth in humans. What exists instead is a broader body of research on peptides, growth factors, and hair follicle biology.

For example, a 2005 study from Kyoto University modified a small peptide (pep7, taken from a protein called epimorphin) and reported that the modified peptide induced hair follicle regeneration in mice. The study involved animals, not humans, and the peptide was not sh‑Polypeptide‑7.

A 2010 paper by researchers at Helix BioMedix, the company that makes the peptide, reported that a wound-healing peptide fragment (hexapeptide‑7) stimulated skin-cell growth and collagen production in the laboratory. In a small study of 32 women (mean age 54), the authors reported improved forehead wrinkles and skin texture. The study was run by the manufacturer, and it does not involve hair follicles or sh‑Polypeptide‑7.

Clinical research into hair regeneration has also explored complex mixtures of growth‑related proteins. A company-sponsored (Histogen) phase 1 trial published in 2011 gave a single injection into the scalp of a cell-derived mixture containing Wnt-pathway factors and follistatin to 26 men with male pattern hair loss. It reported more hair growth at the treated sites than at placebo sites at 12 and 52 weeks. It was a single injection, not a topical product, it included only men, and it did not test sh‑Polypeptide‑7.

sh‑Polypeptide‑7 appears in the EU CosIng cosmetic-ingredient inventory, with the listed functions “anti-sebum” and “skin protecting”. A CosIng listing is not an approval. In the US, the FDA does not pre-approve cosmetic ingredients or require proof that they work, and whether a product may make a given claim depends on how it is marketed. US federal law also separately restricts the distribution of human growth hormone for uses other than an authorised medical use under a doctor's order (21 U.S.C. 333(e)). We do not state whether any particular product is lawful.

When we critically evaluate all available information, a clear pattern emerges. The theoretical basis for using sh‑Polypeptide‑7 is rooted in legitimate biological concepts related to growth hormone signaling and peptide activity. However, the leap from laboratory science to real‑world cosmetic effectiveness has not yet been supported by strong clinical evidence. There is currently no published human trial demonstrating that sh‑Polypeptide‑7 alone, applied topically in a cosmetic serum, leads to measurable hair regrowth or prevents hair loss.

What we therefore need to know as informed consumers or researchers is that sh‑Polypeptide‑7 exists within a gray zone common in advanced cosmetic science. It is based on real molecular biology, but its practical benefits for hair growth remain largely theoretical. Claims that it changes hair follicles have not been supported by controlled human studies, and its safety on the scalp has not been studied. People who are pregnant, breastfeeding, or have diabetes, a history of cancer or a hormone (endocrine) condition should ask a doctor before using a growth-hormone-derived product. In summary, sh‑Polypeptide‑7 is recombinant human growth hormone used in some hair products because of its proposed signaling properties. Scientific research shows that peptides and growth factors can influence hair biology in experimental settings, but there is no direct clinical evidence proving that sh‑Polypeptide‑7 itself promotes hair growth in humans. Its presence in cosmetic products reflects innovation in formulation rather than confirmed therapeutic effectiveness.

References

Hirai, Y., Takebe, K., & Nakajima, K. (2005). Structural optimization of pep7, a small peptide extracted from epimorphin, for effective induction of hair follicle anagen. Experimental Dermatology, 14(9), 692–699. https://pubmed.ncbi.nlm.nih.gov/16098129/

Falla, T. J., & Zhang, L. (2010). Efficacy of hexapeptide‑7 on menopausal skin. Journal of Drugs in Dermatology, 9(1), 49–54. (Authors affiliated with the manufacturer, Helix BioMedix.) https://pubmed.ncbi.nlm.nih.gov/20120425/

Zimber, M. P., Ziering, C., Zeigler, F., Hubka, M., Mansbridge, J. N., Baumgartner, M., Hubka, K., Kellar, R., Perez-Meza, D., Sadick, N., & Naughton, G. K. (2011). Hair regrowth following a Wnt- and follistatin containing treatment: Safety and efficacy in a first-in-man phase 1 clinical trial. Journal of Drugs in Dermatology, 10(11), 1308–1312. https://pubmed.ncbi.nlm.nih.gov/22052313/

European Commission. (n.d.). CosIng – Cosmetic ingredient database: SH-POLYPEPTIDE-7 (substance 87422). https://ec.europa.eu/growth/tools-databases/cosing/details/87422

21 U.S.C. § 333(e). Prohibited distribution of human growth hormone. https://www.law.cornell.edu/uscode/text/21/333

Cosmileeurope. (n.d.). SH‑Polypeptide‑7 ingredient profile. https://cosmileeurope.eu/inci/detail/14380/sh-polypeptide-7/

U.S. Food and Drug Administration. (n.d.). Cosmetic ingredient regulation and safety overview. https://www.fda.gov/cosmetics/cosmetic-ingredient