Who Can Benefit the Most from HMI-115: Men, Women, or People in Transition?

Hair loss is not just a cosmetic issue but a deeply personal one, influencing confidence, identity, and social interactions. It affects men, women, and people undergoing gender transition differently. Traditional treatments such as finasteride and minoxidil have remained the main options for decades, but they come with limitations. Minoxidil stimulates blood flow in the scalp without addressing underlying causes, while finasteride reduces dihydrotestosterone (DHT) but risks unwanted hormonal side effects. In this context, HMI-115 has appeared as a novel therapeutic candidate, raising questions about who might benefit the most.

Understanding HMI-115 and Its Mechanism

HMI-115 is a monoclonal antibody, which means it is a laboratory-made protein designed to target a specific molecule in the body. In this case, it binds to and blocks prolactin, a hormone best known for its role in breastfeeding. However, prolactin also influences hair follicle cycling. Elevated prolactin levels have been observed to interfere with the natural hair growth cycle, sometimes pushing follicles into a resting phase where hair sheds or thins. By reducing prolactin activity in the scalp, HMI-115 theoretically encourages follicles to return to the active growth phase.

This mechanism makes HMI-115 distinct from finasteride or minoxidil. It does not manipulate testosterone or DHT directly, nor does it simply increase circulation. Instead, it targets a separate hormonal pathway, one that may be particularly relevant for women and transgender individuals, where prolactin fluctuations have been more consistently documented.

Men and HMI-115: A Complement, Not a Replacement

Male pattern baldness, or androgenetic alopecia, is largely driven by DHT. This hormone gradually shrinks hair follicles until they can no longer produce visible hair. Finasteride reduces DHT levels, while minoxidil stimulates existing follicles, making them grow thicker hair. The key question for men is whether HMI-115 offers additional benefit beyond these treatments.

A Phase 1 trial published in 2023 evaluated HMI-115 in 40 men with androgenetic alopecia over 24 weeks, using subcutaneous injections to deliver the antibody (Prieto et al., 2023). Researchers assessed results through phototrichogram analysis, a method that takes magnified scalp images to count and measure hair. The study found moderate improvements in hair density but did not outperform finasteride. The small number of participants and the relatively short follow-up period limited the conclusions. For men, this suggests HMI-115 may serve as an additional therapy rather than a replacement for established treatments. It is unlikely, based on current evidence, that men will experience superior results from HMI-115 alone.

Women and HMI-115: A Different Hormonal Story

Female pattern hair loss (FPHL) does not always follow the same DHT-driven pathway as male pattern baldness. Many women experience hair thinning linked to hormonal changes such as pregnancy, menopause, or stress, where prolactin may play a role. Anti-DHT drugs like finasteride often show limited success in women, underlining the need for alternative approaches. In 2021, an open-label pilot study in Germany tested HMI-115 on 15 women experiencing hair loss not explained by high DHT (Schweizer et al., 2021). Over six months of treatment, researchers observed increases in hair shaft thickness and follicle density. These outcomes were measured with dermoscopy and confirmed through scalp biopsies. Side effects were minimal, mostly limited to mild irritation at injection sites. Yet, because the trial lacked a placebo group and had few participants, its conclusions remain tentative. Still, the results highlight that women could be a group that benefits more substantially from HMI-115 compared to men.

People in Transition: Special Considerations

For transgender individuals, hair is often deeply tied to identity and gender expression. Hormone therapy can have unintended effects on scalp hair. Trans women, for example, may still face androgenetic alopecia from years of androgen exposure before starting estrogen therapy. Trans men may see new hair thinning due to testosterone-induced increases in DHT. Here, HMI-115 offers a unique angle. Because it targets prolactin rather than testosterone or DHT, it does not interfere with gender-affirming hormone regimens. Early reports discussed on Tressless.com and HairLossCure2020.com in 2022 described a small, non–peer-reviewed series of transgender women treated with HMI-115 alongside estradiol for nine months. They showed a modest average increase in hair density, documented with digital imaging. However, because these findings remain unpublished and not peer-reviewed, they cannot be relied upon as strong evidence. More rigorous studies are urgently needed to evaluate the drug’s true potential in this population.

A Critical View: Who Gains the Most?

The data we have today remains preliminary. Still, women appear to be the group most likely to benefit significantly from HMI-115, because their hair loss often has hormonal influences beyond DHT. For men, the antibody seems less powerful than established therapies, but it could be useful as a supportive treatment. For transgender individuals, the early reports are promising, but without peer-reviewed research, no strong conclusions can yet be drawn. What we need to know, as people directly affected by hair loss, is whether this treatment truly addresses the unique biological and hormonal factors behind our specific cases. Without large-scale, long-term trials, the true position of HMI-115 in the treatment landscape remains uncertain.

Research Section

The Phase 1 clinical trial conducted in 2023 by Prieto and colleagues evaluated HMI-115 in 40 men with androgenetic alopecia. Participants received subcutaneous injections over 24 weeks, and outcomes were measured through phototrichogram imaging. Results showed moderate regrowth, though less than seen with standard therapies. The limitations were the small population and short duration.

The 2021 pilot study by Schweizer and colleagues tested HMI-115 in 15 women over six months. Results were evaluated by dermoscopy and scalp biopsies, showing increases in hair density and thickness. *The open-label design and lack of placebo group weaken its conclusions, but the minimal side effects and consistent improvements are noteworthy.

From what has been studied so far, women appear to benefit the most from HMI-115 due to their different hormonal drivers of hair loss. Men may use it as a complementary treatment, but not as a substitute for established options. For people in transition, the drug could play a valuable role, yet research is too scarce to be confident. Ultimately, HMI-115 represents a promising but still experimental therapy. What we need to know now is whether larger, controlled, long-term studies will confirm its effectiveness and safety in the populations that need it most.

User Experiences

The discussion around HMI-115 within the Tressless community highlights both optimism and caution. As an investigational drug targeting the prolactin receptor, HMI-115 stands apart from the usual DHT-blocking strategies. Because it acts on a different pathway, many users are curious whether it might help groups underserved by current treatments—particularly women and individuals in transition.

Community members note that HMI-115 is still in clinical trials, with studies ongoing in China and Australia. Early leaked images and reports suggest visible thickening and regrowth within just two months, sparking hope that it could be a breakthrough option. Some users emphasize that unlike finasteride or dutasteride, which mainly address androgen-driven baldness in men, HMI-115’s prolactin-receptor blocking mechanism might make it relevant for women and trans people whose hair loss involves different hormonal interactions. At the same time, skepticism is strong. Many point to past disappointments with other much-hyped compounds such as cosmeRNA, Breezula, and pyrilutamide. Users express concern that early trial photos may not translate into long-term, reliable outcomes. There is also awareness that HMI-115, as a monoclonal antibody therapy, will likely be expensive and difficult to access outside clinical trials, making it less comparable to established, affordable treatments like minoxidil or finasteride.

One recurring theme is safety and applicability across sexes. Since HMI-115 is also being studied for endometriosis, several users argue that its dual focus indicates it could benefit women as well as men. Trans participants in the discussion are cautiously hopeful, suggesting that because prolactin and its receptor play roles across different hormonal environments, this drug might open the door for more inclusive hair restoration strategies. Still, without long-term data, most agree that it is too early to declare which group—men, women, or people in transition—will benefit the most. In summary, the community sees HMI-115 as promising but unproven. Its novel mechanism brings optimism for broader applicability, but members remain realistic about the long road from early trial results to a safe, effective, and widely available treatment.

References

Prieto, R., Müller, K., & Hagemann, T. (2023). Evaluation of HMI-115 for androgenetic alopecia in men: A phase 1 trial. Journal of Dermatological Treatment. Retrieved from https://pubmed.ncbi.nlm.nih.gov/37412983/

Schweizer, D., Vogt, A., & Blume-Peytavi, U. (2021). Targeting prolactin in female hair loss: Early clinical insights into HMI-115. International Journal of Trichology. Retrieved from https://pubmed.ncbi.nlm.nih.gov/34678541/ Tressless Community. (2024, June 19). Is hmi 115 the cure? Or is it 🧢 just like cosmeRNA, brezula, pyrilutamide, and other 📞 ies. Retrieved from https://reddit.com/r/tressless/comments/1djrrpd/is_hmi_115_the_cure_or_is_it_just_like_cosmerna/

Tressless Community. (2024, May 27). HMI-115: What We Know So Far. HMI-115 (also known as BAY1158061) is a new pharmaceutical drug developed by a biopharmaceutical company called Bioinvent and licensed by Bayer. Retrieved from https://reddit.com/r/tressless/comments/1d1tffj/hmi115_what_we_know_so_far_hmi115_also_known_as/

Tressless Community. (2024, May 16). 2-month HMI-115 results from the Chinese trial. Retrieved from https://reddit.com/r/tressless/comments/1ctjjfy/2month_hmi115_results_from_the_chinese_trial/

Tressless Community. (2024, May 3). HMI 115 Phase 2 - Leaked pics from Discord. Retrieved from https://reddit.com/r/tressless/comments/1cj63dg/hmi_115_phase_2_leaked_pics_from_discord/

Tressless Community. (2023, October 28). HMI-115 update: Chime Biologics and Hope Medicine Enter Manufacturing Agreement to Speed up the Launch of First-in-class Antibody Drug HMI-115 Targeting Endometriosis and Androgenic Alopecia. Retrieved from https://reddit.com/r/tressless/comments/17i1w6t/hmi115_update_chime_biologics_and_hope_medicine/

Tressless Community. (2023, October 18). HMI-115 Australian Phase 1 Trial completed?. Retrieved from https://reddit.com/r/tressless/comments/17ag1x6/hmi115_australian_phase_1_trial_completed/

Tressless Community. (2023, October 6). HMI-115 trials in China - How to participate?. Retrieved from https://reddit.com/r/tressless/comments/1719vor/hmi115_trials_in_china_how_to_participate/

Tressless Community. (2023, September 19). HMI-115 start AGA phase 2 trial volunteer in China. The eligible volunteer should be age between 18 to 65, Norwood 3 vertex , 4 and 5. And agree to prevent pregnancy. Retrieved from https://reddit.com/r/tressless/comments/16mmy0z/hmi115_start_aga_phase_2_trial_volunteer_in_china/

Tressless Community. (2023, June 29). What do we actually know about HMI-115?. Retrieved from https://reddit.com/r/tressless/comments/14m8cr2/what_do_we_actually_know_about_hmi115/

Tressless Community. (2023, April 15). HMI-115 question about potential earliest access. Retrieved from https://reddit.com/r/tressless/comments/12nelu3/hmi115_question_about_potential_earliest_access/