Is Topical Bicalutamide a Safer Alternative to Finasteride?

Finasteride has long been one of the most commonly used treatments to combat hair loss in men, especially in cases of androgenetic alopecia, also known as male pattern baldness. Over time, however, significant concerns have emerged regarding its side effects, particularly in its oral form. This has prompted the search for other therapeutic options, including the topical use of drugs that were previously only used systemically. Among these, topical bicalutamide has garnered particular attention. Could this alternative be safer than finasteride? This is the question we aim to explore in depth, based on official research.

What is Finasteride Used For and How Is It Consumed?

Finasteride is an FDA-approved medication for treating androgenetic alopecia in men and is also used for benign prostatic hyperplasia (enlarged prostate). Its mechanism of action involves inhibiting an enzyme called 5-alpha reductase type II, which converts testosterone into dihydrotestosterone (DHT). DHT is the hormone primarily responsible for the miniaturization of hair follicles in male pattern baldness. The most common form of finasteride is oral, typically taken at a dosage of 1 mg per day for hair loss and 5 mg per day for prostate issues. In recent years, it has also begun to be used topically in an effort to limit systemic side effects. In this format, typical concentrations range from 0.25% to 0.5%, equivalent to approximately 2.5 mg to 5 mg per ml of solution, depending on the manufacturer and the vehicle used.

However, it is important to note that even in its topical form, small amounts of finasteride can enter the bloodstream, potentially causing side effects in some individuals.

What is Bicalutamide and How Does It Work on Hair?

Bicalutamide is a non-steroidal antiandrogen originally developed and approved for the treatment of prostate cancer. Its main function is to block androgen receptors, preventing hormones like testosterone or DHT from binding to cells and triggering biological processes. Unlike finasteride, which reduces the production of DHT, bicalutamide works by directly blocking its action on tissues. This mechanism has drawn the attention of researchers in hair dermatology, as androgenetic alopecia is caused precisely by the action of DHT on hair follicles. By preventing this hormone from acting on the scalp, bicalutamide may protect follicles and stimulate hair growth. In its oral form, it is typically used at a dosage of 50 mg per day for more severe hormonal conditions, though this use is not approved for hair loss. In its topical form, studied concentrations generally range from 0.5% to 1% (equivalent to 5 mg to 10 mg per ml).

Is Topical Bicalutamide Safer Than Oral Finasteride?

This is one of the most relevant questions for people who want to treat hair loss without exposing themselves to the side effects associated with oral finasteride. To answer it, we analyzed several scientific studies published in recent years. A 2021 study published in the journal "Skin Appendage Disorders" by Italian researchers evaluated the topical use of bicalutamide in men with androgenetic alopecia. This was a pilot study that included 16 male participants and lasted six months. The subjects applied a 0.5% bicalutamide solution once a day. Results were assessed using photographic hair counts (phototrichogram) and hair density measurements. Researchers found a mild but consistent improvement in hair density, with no systemic side effects such as sexual dysfunction or hormonal changes in blood tests. The main critique of this study is its small sample size and lack of a control group, which limits the strength of its conclusions.

In comparison, oral finasteride has been extensively studied. One of the most cited studies was published in 1998 in the "Journal of the American Academy of Dermatology." This double-blind clinical trial included 1,553 men over a two-year period. Results showed that 83% of participants taking 1 mg of oral finasteride daily halted their hair loss, and many even experienced new growth. However, 1.8% reported sexual side effects such as reduced libido, erectile dysfunction, or decreased ejaculatory volume. While the authors considered these side effects reversible, later studies have noted that, in some cases, symptoms persist after discontinuing the drug (a condition known as post-finasteride syndrome).

What About Topical Finasteride?

A 2020 study published in the journal "Dermatologic Therapy" compared 0.25% topical finasteride to the oral form in 120 male patients over 24 weeks. Both groups showed improvement in hair density, evaluated through digital dermatoscopy, although the topical group reported far fewer systemic side effects. However, low levels of finasteride were detected in the blood of some topical users, indicating partial absorption. This suggests that while it is safer, it is not entirely free from risk.

Another relevant study on the safety of topical bicalutamide was published in 2022 in the "International Journal of Trichology." This observational analysis involved 30 patients (both men and women) with androgenetic alopecia treated with 1% bicalutamide gel over six months. No significant adverse events were reported, and blood tests showed no hormonal changes. Researchers highlighted good skin tolerance and the formula’s stability. Nevertheless, this study was also neither controlled nor randomized, which weakens its scientific weight.

User Experiences: Is Topical Bicalutamide a Safer Alternative to Finasteride?

In the Tressless community, a recurring discussion surrounds whether topical bicalutamide, a non-steroidal antiandrogen, is a safer or more targeted option than oral finasteride for treating androgenic alopecia. While finasteride is an FDA-approved, systemic treatment that works by inhibiting 5-alpha-reductase and reducing serum dihydrotestosterone (DHT), bicalutamide acts by blocking androgen receptors, with potentially fewer systemic hormonal effects when applied topically. But does this theory hold up in practice? Here's what users have reported. In discussions such as this post, one female user noted considering bicalutamide as part of a broader antiandrogen protocol including estrogen and spironolactone. This reflects a trend in the community where topical bicalutamide is often explored by women or trans individuals, particularly when systemic DHT suppression from finasteride is not ideal or causes undesirable effects.

Other users reference bicalutamide in combination with topical estrogens or tretinoin, with the intention of achieving local antiandrogenic activity without affecting testosterone levels or risking systemic sexual side effects. This is a major point of divergence from finasteride, which can alter hormone balance and is sometimes linked to libido changes, erectile dysfunction, and depression. In male users, however, enthusiasm is more tempered. Some note concern about systemic absorption, pointing out that bicalutamide—while effective in prostate cancer treatment—is not officially approved for hair loss, and its long-term safety profile as a topical agent is understudied. Despite this, a few anecdotal cases report perceived hair maintenance or regrowth without finasteride’s typical side effects. An older but still frequently cited post discusses the possible use of bicalutamide and compares its safety to RU58841 and flutamide. While RU58841 and clascoterone are more well-known among topical antiandrogens, bicalutamide has drawn interest due to its strong receptor affinity and non-steroidal mechanism.

Conclusion: Is Topical Bicalutamide Safer Than Finasteride?

Current studies suggest that yes, topical bicalutamide may represent a safer alternative to oral finasteride, particularly for those concerned about sexual side effects. Its mechanism of directly blocking androgen receptors in the scalp, along with limited systemic absorption, makes it a promising option. However, larger, controlled, and long-term studies are still needed to confirm its true effectiveness and full safety profile. Oral finasteride, on the other hand, has years of solid evidence behind it—but also a well-documented history of side effects in some users.

In the meantime, topical finasteride appears to be a middle ground: an option that maintains the efficacy of the oral version while reducing absorption and therefore unwanted effects. Still, even in its topical form, it is not entirely risk-free.

References

• Rossi, A., Anzalone, A., Garelli, V., Maxia, C., Scali, E., Fortuna, M. C., & Carlesimo, M. (2021). Topical bicalutamide in the treatment of androgenetic alopecia: A pilot study. Skin Appendage Disorders, 7(5), 343–349. https://doi.org/10.1159/000516070

• Kaufman, K. D., Olsen, E. A., Whiting, D., Savin, R., DeVillez, R., Bergfeld, W., ... & Finasteride Male Pattern Hair Loss Study Group. (1998). Finasteride in the treatment of men with androgenetic alopecia. Journal of the American Academy of Dermatology, 39(4), 578–589. https://doi.org/10.1016/S0190-9622(98)70007-6

• Caserini, M., Radicioni, M., Leuratti, C., Annoni, O., & Marrè Brunenghi, G. (2020). A randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of a new topical finasteride formulation in men with androgenetic alopecia. Dermatologic Therapy, 33(6), e14137. https://doi.org/10.1111/dth.14137

• Villarreal‐Villagrana, E. M., & Moreno‐Ramírez, D. (2022). Safety and efficacy of topical bicalutamide in male and female pattern hair loss: An observational study. International Journal of Trichology, 14(1), 8–13. https://www.ijtrichology.com/text.asp?2022/14/1/8/341682

• FDA. (2024). Drug Label for Finasteride. U.S. Food and Drug Administration. https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/020788s041lbl.pdf

• Perfect Hair Health. (n.d.). Is topical finasteride safer than oral? Retrieved May 2025 from https://perfecthairhealth.com/topical-finasteride/

• Hair Loss Cure 2020. (n.d.). Bicalutamide for Hair Loss – Topical Anti-Androgens. Retrieved May 2025 from https://www.hairlosscure2020.com/topical-bicalutamide-for-hair-loss/