What role does Osteopontin play in protecting and repairing hair follicles?

When exploring why hair follicles weaken or disappear, many people turn to explanations involving hormones, nutrition, or blood circulation. But what if another molecule, one less commonly mentioned, was quietly influencing whether our follicles survive or collapse? That molecule is osteopontin (OPN). Initially studied in bone health and immune responses, osteopontin has more recently drawn attention in hair research after mouse studies linked it to the activation of hair stem cells. The critical question for us is whether osteopontin truly protects follicles in a meaningful way, or whether its effects are indirect and overstated.

What is osteopontin and why does it matter?

Osteopontin is a glycoprotein, which means it is a protein molecule combined with sugar chains. This structure makes it especially good at attaching to other cells and transmitting signals. In biological terms, it works as a signaling molecule. It alerts cells when to survive, when to divide, and when to repair damage. Because hair follicles are exposed to constant cycles of growth and rest, along with stress from inflammation and oxidative molecules known as free radicals, researchers have asked whether a protein like osteopontin affects how follicles respond. That question has not been answered for human hair loss.

How might osteopontin affect hair follicles?

The follicle cycle—anagen (growth), catagen (regression), and telogen (rest)—is a vulnerable process. When inflammation, hormonal shifts, or oxidative stress interfere with this cycle, follicles risk entering premature rest or shrinking permanently. In many tissues, osteopontin acts through integrins (proteins that link cells to their surrounding support structures) and CD44 receptors (involved in tissue repair). In the best-documented hair study, described below, osteopontin acting on CD44 switched on hair stem cells in mice. Whether osteopontin protects human follicles from stress or damage has not been shown.

Research evidence: osteopontin in follicle biology

In 2023, Wang and colleagues reported in Nature that clusters of aged (senescent) pigment cells in mouse skin moles release osteopontin, and that osteopontin acting on the CD44 receptor pushes hair stem cells out of rest. Injecting osteopontin, or overexpressing it genetically, produced strong hair growth in mice, and removing osteopontin or CD44 removed the effect. The authors also reported that osteopontin is overexpressed in human hairy moles and that it stimulated growth in human hair follicles studied outside the body. This is a mechanism study in mice and isolated human follicles, not a treatment study in people. Some authors are connected to a company developing the finding commercially, as the paper discloses (Wang et al., 2023).

A human-tissue study points the other way. In 2020, Alam and colleagues tested an osteopontin-derived peptide, FOL-005, on organ-cultured human hair follicles, human scalp skin, and human scalp skin grafted onto mice. The peptide pushed follicles early into the regression (catagen) phase, and the authors proposed it as a possible treatment for unwanted hair growth. The work was co-authored by the company developing the peptide (Alam et al., 2020).

A critical look at current findings

If we step back, we must recognize that the research so far is promising but not definitive. The two main studies point in opposite directions, and neither tested a treatment in people. However, most of the evidence is indirect. Studies are short-term, often lasting weeks, whereas human hair loss evolves over years. Populations are limited to mice or cultured cells, not large groups of people. Another concern is that osteopontin is not follicle-specific. It is involved in processes as broad as cancer progression, tissue fibrosis, and immune system regulation. This raises potential risks: stimulating osteopontin to help hair might unintentionally worsen other conditions. What we need to know, then, is not only whether osteopontin protects hair follicles but also whether it can be safely targeted in humans. To date, no clinical trial of an osteopontin-based therapy for hair loss has been published in a journal. The peptide's developer, Follicum, tested a topical FOL-005 formulation for 16 weeks in 210 men with hair loss; its 2021 top-line press release reported no significant difference from placebo (p=0.83), and the results have not been published in a journal. Until better evidence exists, osteopontin remains a research subject, not a medical treatment.

Could osteopontin shape future treatments?

Interest in osteopontin comes mainly from the mouse finding that it can switch on hair stem cells. If that effect could be reproduced safely in people, it might offer a new approach, but this has not been shown. However, without precise delivery methods and safety assurances, such therapies remain speculative. What we need to understand next is how osteopontin can be applied specifically to hair follicles without triggering unwanted effects elsewhere in the body.

Whether osteopontin protects human hair follicles is not known. In mice it activated hair growth (Wang et al., 2023); in human scalp tissue, an osteopontin-derived peptide did the opposite (Alam et al., 2020). However, until human clinical data are available, we must regard osteopontin not as a guaranteed protector of follicles but as a potentially significant yet unproven factor. For those of us seeking reliable answers on hair loss, the current state of research offers hope but also caution.

User Experiences: Osteopontin and Hair Follicle Protection

In the Tressless community, discussions about osteopontin often center on its potential role in regulating the hair cycle and influencing new therapeutic approaches. Osteopontin is a multifunctional protein involved in tissue repair, inflammation, and cell signaling, and researchers have investigated whether it helps maintain or disrupt hair follicle health.

Community members point out that companies like Coegin Pharma are exploring osteopontin-derived peptides such as FOL-005, designed to modify hair follicle activity. Some users hope these peptides could compete with finasteride, but no published trial supports that: the developer’s own topical trial initially reported no significant benefit over placebo. Community posts report plans to sell the peptide as a cosmetic rather than a drug. A cosmetic does not go through drug-level review of efficacy or safety, and many users question results for that reason.

Another angle of discussion highlights delivery methods. Posters debate whether technologies like iontophoresis and sonophoresis—which use electrical currents and sound waves to push compounds deeper into the skin—might enhance the penetration of osteopontin-based treatments. This reflects broader interest in how peptides, which typically struggle to cross the skin barrier, might finally become viable for topical therapy. However, not all sentiment is hopeful. Some contributors warn that osteopontin-related peptides may end up being more effective at suppressing hair growth rather than stimulating it, depending on how they interact with growth factors such as FGF7. This is why several community members emphasize the importance of careful clinical testing before relying on osteopontin-based products.

In summary, osteopontin is seen by the community as both a potential breakthrough and a source of uncertainty. While ongoing trials and biotech interest keep the conversation alive, users remain cautious, waiting to see whether these therapies will truly support follicle protection and regrowth, or whether their role will be more aligned with controlling unwanted hair growth.

References

Wang, X., Ramos, R., Phan, A. Q., et al. (2023). Signalling by senescent melanocytes hyperactivates hair growth. Nature, 618(7966), 808–817. PMID: 37344645. https://pubmed.ncbi.nlm.nih.gov/37344645/

Alam, M., Bertolini, M., Gherardini, J., et al. (2020). An osteopontin-derived peptide inhibits human hair growth at least in part by decreasing fibroblast growth factor-7 production in outer root sheath keratinocytes. British Journal of Dermatology, 182(6), 1404–1414. PMID: 31487385. https://pubmed.ncbi.nlm.nih.gov/31487385/

Follicum AB. (2021, May 6). Follicum reports top-line results from Phase IIa study of FOL-005 for treatment of hair loss (alopecia) [Press release]. https://news.cision.com/follicum/r/follicum-reports-top-line-results-from-phase-iia-study-of-fol-005-for-treatment-of-hair-loss--alopec,c3341890

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Tressless Community. (2024, September 15). Coegin Pharma to release Follicopeptide (FOL005) by Q2 2025. Retrieved from https://reddit.com/r/tressless/comments/1fh9yhi/coegin_pharma_to_release_follicopeptide_fol005_by/

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