Two questions bring anyone to this subject: does it stop, and does it grow back. The honest answer to both is that it depends entirely on which treatment you pick — and the gap between the options is not small. It is 89 randomised trials against two.
Male pattern hair loss is driven by dihydrotestosterone, the potent form of testosterone. Follicles that are genetically sensitive to DHT miniaturise: each cycle produces a finer hair, until it produces nothing. That mechanism is why most of what is sold for hair does nothing — it is not aimed at the thing causing the problem.
Every option, and the trials behind it
Counts run against PubMed on 1 September 2026, restricted to randomised controlled trials. The exact searches are printed further down so you can repeat any of them in about a minute.
| Treatment | Randomised trials | What it does |
|---|---|---|
| Minoxidil, topical FDA-approved | 89 | The most-studied option there is. Works on the growth phase, not on DHT. |
| Finasteride, oral 1 mg FDA-approved | 48 | Blocks the conversion of testosterone to DHT, which is the mechanism driving the loss. |
| Microneedling adjunct | 9 | Studied mostly with minoxidil rather than against it. |
| Low-level laser FDA-cleared | 8 | Cleared, not approved — a lower bar. Effects are real but small. |
| Dutasteride off-label for hair | 7 | Same mechanism as finasteride, approved for prostate rather than hair. |
| Saw palmetto supplement | 6 | Sold as a natural DHT blocker. Six trials against finasteride's 48. |
| Biotin supplement | 2 | The best-selling hair supplement in the world. |
| Rosemary oil cosmetic | 2 | Everywhere on social media. Two trials. |
Read that column from the bottom and the picture is uncomfortable. The products a person can buy off a shelf tonight — biotin, rosemary oil, saw palmetto — carry two, two and six trials. The two treatments with 89 and 48 are the two the FDA has approved, and both require a prescription in most places.
The biotin problem
Biotin is the best-selling hair supplement in the world. A review in Skin Appendage Disorders went looking for the evidence and found 18 reported cases of biotin improving hair or nails.
Every single one had a deficiency underneath it
In all 18 cases the patient had an underlying pathology causing poor hair growth — inherited or acquired biotin deficiency, brittle nail syndrome, uncombable hair syndrome. Biotin corrected the deficiency. There is no evidence it does anything in someone who is not deficient, and deficiency is rare.
That is the shape of most of this market: a real effect in a small group with a specific problem, sold to everyone else as a general solution.
What the two approved treatments actually do
Finasteride works on the cause. It inhibits the enzyme that converts testosterone into DHT, which lowers the signal telling those follicles to miniaturise. It is the only widely available treatment aimed at the mechanism rather than the symptom.
Minoxidil works on the growth phase instead, extending the period a follicle spends producing hair. It does nothing about DHT, which is why the two are frequently studied together rather than against each other.
The 2017 systematic review and meta-analysis in the Journal of the American Academy of Dermatology assessed these against placebo for hair density, thickness, and growth, and reported that minoxidil and finasteride are the only treatments the FDA recognises as treatments for androgenetic alopecia. Low-level laser is cleared rather than approved, which is a lower regulatory bar.
Which means the first step is not a purchase
There is a second reason to stop before buying anything, and it is the one most people get wrong.
Pattern loss is not the only kind. Telogen effluvium — shedding triggered by rapid weight change, illness or stress — looks alarming, is diffuse rather than patterned, and resolves on its own over months without any product at all. The follicles are resting, not dying. Buying finasteride for it is money spent on the wrong condition.
Telling the two apart is a clinical question. It is also the only question worth answering before spending anything, because the answer decides whether treatment is necessary or pointless.
Both of the two that work need a prescription
That is the conclusion of the table above, and it is not a sales line — it is why minoxidil and finasteride have 89 and 48 trials while everything on the shelf has two. The FDA approved them; the shelf products were never put through the same test.
Which also means the first step is not a purchase. Whether you have pattern loss that needs treating or shedding that resolves by itself decides whether any of this applies to you at all, and that is diagnosable in a consultation rather than guessable from an article.
Which one you have is the whole question, and it is not one an article can answer. Hims connects you with licensed providers who can tell them apart, covering the whole category rather than selling you one drug before anyone has looked. What gets prescribed, if anything, is their call.
The Iron Verdict earns a commission if you subscribe. It changes nothing above — including the part that says the common type needs no treatment at all.
Find out which one you have →Available in the United States only. This is not medical advice, and nothing here is a recommendation to take any medication.
The searches, so you can check the table
Paste any of these into PubMed exactly as written. The counts drift as trials report; where this page and PubMed disagree, PubMed is right and this page is out of date.
"minoxidil" AND "androgenetic alopecia" AND randomized controlled trial[pt]
"finasteride" AND "androgenetic alopecia" AND randomized controlled trial[pt]
"microneedling" AND "androgenetic alopecia" AND randomized controlled trial[pt]
("low-level laser therapy" OR "photobiomodulation") AND "androgenetic alopecia"
AND randomized controlled trial[pt]
"dutasteride" AND "androgenetic alopecia" AND randomized controlled trial[pt]
("saw palmetto" OR "serenoa repens") AND alopecia AND randomized controlled trial[pt]
"biotin" AND ("hair loss" OR alopecia) AND randomized controlled trial[pt]
"rosemary" AND alopecia AND randomized controlled trial[pt]
References
- Adil A, Godwin M. The effectiveness of treatments for androgenetic alopecia: A systematic review and meta-analysis. J Am Acad Dermatol 2017;77(1):136–141.e5. PMID 28396101.
- Patel DP, Swink SM, Castelo-Soccio L. A Review of the Use of Biotin for Hair Loss. Skin Appendage Disord 2017;3(3):166–169. PMID 28879195.
- Almohanna HM, et al. The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatol Ther (Heidelb) 2019;9(1):51–70. PMID 30547302.
- Trial counts: PubMed, queried 1 September 2026, filtered to randomised controlled trials.
This page reports published research. It is not medical advice, contains no doses, and is not a recommendation to take any medication. What is appropriate for you is a conversation with a clinician who can examine you.