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This article summarizes published evidence — FDA-approved drug labels and the randomized trials behind them, each cited below. It is written by journalists, not clinicians, and has not been reviewed by a physician. Talk to a doctor or a board-certified dermatologist before starting or stopping any treatment. Full medical disclaimer.
What the status labels on this page mean
- FDA-approved
- The FDA reviewed the evidence and approved this drug for pattern hair loss.
- FDA-cleared
- Allowed on the market through the 510(k) route because it is judged similar to a device already sold — not the same as the FDA independently approving its effectiveness.
- Off-label
- An FDA-approved drug being prescribed for something other than what it was approved for. Legal and common, but the hair loss use has not been through FDA review.
- Compounded
- Mixed to order by a pharmacy. Not FDA-approved, and not reviewed by the FDA for safety, effectiveness or quality.
- Supplement
- A dietary supplement. The FDA does not approve supplements before they go on sale, and claims about them are not FDA-evaluated.
What this page found
- Exactly two drugs are FDA-approved for pattern hair loss: oral finasteride FDA-approved and topical minoxidil FDA-approved. Everything else in this category is off-label, compounded, a cleared device, or a supplement.[1, 4, 5]
- They work on different things. Finasteride reduces the hormone that shrinks follicles. Minoxidil acts locally on the growth phase of follicles that are still there.
- The headline number for finasteride is +107 hairs in a one-inch circle versus placebo at 12 months, and +138 at 24 months, from the trial program in the FDA label.[1, 2]
- The most important line in either label is about stopping: for minoxidil, the FDA label says you will likely lose the new hair within three to four months of quitting.[4]
- Neither drug regrows a follicle that is gone. Both are better at holding a line than redrawing one.
The only two approved drugs, and why that matters
Pattern hair loss has one of the clearest regulatory pictures in consumer health, and almost none of the marketing reflects it. Two drugs have been reviewed by the FDA and approved for it: finasteride taken as a tablet, and minoxidil applied to the scalp.[1, 4, 5] That is the entire approved list.
This matters because most of what is sold for hair loss is one of those two molecules delivered a different way, at a much higher price, in a form the FDA has not approved. Knowing what the two originals do is what lets you evaluate everything else.
What DHT does to a follicle
Pattern hair loss is a hormonal process acting on genetically susceptible follicles. The hormone is dihydrotestosterone, or DHT, which the body makes from testosterone using an enzyme called 5-alpha-reductase.
In susceptible follicles, DHT drives miniaturization: with each growth cycle the follicle produces a slightly finer, shorter, less pigmented hair, and spends less of its cycle actively growing. The follicle does not vanish overnight. It shrinks by degrees, until what it makes is a barely visible vellus hair rather than a terminal one. That is why the thinning looks gradual and why the pattern is so consistent between people.
Two consequences follow, and they explain almost everything about how these drugs behave. First, the earlier you interrupt the process, the more follicles are still capable of producing a terminal hair. Second, because the driver is ongoing, removing the treatment lets the process resume.
Finasteride: reducing the signal
Finasteride inhibits 5-alpha-reductase type II, the enzyme that converts testosterone into DHT. Less DHT reaching susceptible follicles means less miniaturization pressure on them.
The drug is a 1 mg daily tablet, approved for men only. The FDA label states plainly that it is not indicated for use in women, and finasteride is contraindicated in women who are or may become pregnant.[1] We cover why in our guide to female pattern hair loss.
What the trial found
Kaufman KD, Olsen EA, Whiting D, et al. Journal of the American Academy of Dermatology, 1998
- Design
- Double-blind, placebo-controlled randomized trial, two years
- Participants
- 1,553 men aged 18–41
- Main result
- Hair count in a one-inch circle was 107 hairs higher than placebo at 12 months and 138 higher at 24 months. In investigator assessment, 65% of treated men were rated as having increased hair growth versus 37% on placebo; a panel reviewing photographs rated 48% improved versus 7%. In the placebo group, 58% continued to lose hair.[1, 2]
Stated limitation: The trial enrolled men aged 18–41 with mild to moderate vertex hair loss. It does not tell you what happens in older men, in more advanced loss, or in women.
Sources: FDA-approved label for PROPECIA[1] and the published trial[2].
A five-year extension followed 1,215 of those men and reported that the improvement was maintained while the placebo group kept losing ground.[3] We have not been able to obtain the year-by-year hair counts from the full text, so we are not quoting three- and five-year numbers.
Minoxidil: acting on the follicle directly
Minoxidil started life as an oral drug for severe high blood pressure. It is a vasodilator — it widens blood vessels — and unexpected hair growth turned out to be one of its effects.[9] Applied to the scalp, it appears to shorten the resting phase of the hair cycle and push follicles back into an active growth phase, and it increases local blood flow around them.
Topical minoxidil is sold over the counter as a 2% solution and a 5% solution or foam. The 5% strength is the one with the better trial result in men.
What the trial found
Olsen EA, Dunlap FE, Funicella T, et al. Journal of the American Academy of Dermatology, 2002
- Design
- Randomized, placebo-controlled trial, 48 weeks
- Participants
- 393 men aged 18–49: 5% (n=157), 2% (n=158), placebo (n=78)
- Main result
- 5% minoxidil was significantly superior to both 2% and placebo on non-vellus hair count, produced 45% more hair regrowth than 2% at week 48, and worked faster. Itching and local irritation were more common at 5%.[6]
Stated limitation: Absolute hair counts per group are not given in the abstract and we could not obtain the full text, so we report the relative figure the study reported rather than inventing an absolute one.
Source: published trial[6].
What the trials actually measured
Hair counting in these studies is done in a small marked area of scalp — typically a circle one inch across — not across the whole head. That is a legitimate way to run a trial, but it means the headline numbers describe density in a defined patch, not a total.
| Finasteride 1 mg oral | Minoxidil 5% topical | |
|---|---|---|
| FDA status for hair loss | FDA-approved (men only)[1] | FDA-approved (OTC)[4, 5] |
| Mechanism | Reduces DHT by inhibiting 5-alpha-reductase type II | Acts locally on the hair growth cycle; vasodilator |
| Route | Daily tablet, prescription | Applied to the scalp, over the counter |
| Headline trial result | +107 hairs vs placebo at 12 months; +138 at 24[1, 2] | 45% more regrowth than 2% at 48 weeks[6] |
| Trial size | 1,553 men[2] | 393 men[6] |
| Approved for women? | No — label states it is not indicated for women[1] | Yes, 5% aerosol approved for women in 2014[5] |
How long it takes, and what happens when you stop
Straight from the FDA-approved label
On timing: results “may occur at 3 months” with once-daily use, and for some people “at least 6 months” of use may be needed.[4]
On stopping: if you stop using it, “normal hair loss will start again” and “you will likely lose the new hair you have grown in three to four months.”[4]
Women’s Rogaine 5% Topical Aerosol Drug Facts label, 2019.
That second line is the part worth reading twice. These are not courses of treatment with an end date. The honest way to think about starting either drug is that you are deciding whether to keep doing something indefinitely — which is also why the annual cost matters more than the monthly price. We priced every route in what hair loss treatment actually costs per year.
What neither drug does
- Neither brings back a follicle that is gone. They act on follicles that are still cycling, however weakly. Scalp that has been completely bare for years is not what these trials studied.
- Neither is a cure. They suppress or counteract an ongoing process. The process resumes when they stop.
- Neither treats non-pattern hair loss. Shedding after illness, childbirth, a crash diet or severe stress is a different mechanism, and a DHT blocker is not aimed at it.
- Neither works the same for everyone. The trial numbers are averages. A minority of participants in the placebo groups also improved, and a minority on the drug did not.
Working out which one you are a candidate for
Both of these are decisions for a clinician who can look at your scalp, and the first question is whether what you have is pattern hair loss at all. Sesame Care is a US marketplace that lists what a consultation costs upfront in cash, including hair loss visits, so you can see the price before you book.
Sesame Care is a US telehealth marketplace that lists upfront cash prices for appointments. The link below is an affiliate link: if you book, we may earn a commission at no extra cost to you.
See hair loss consultation prices →Everything else, and where it sits
Once you know what the two approved drugs are, the rest of the market sorts itself into three groups.
| Product | Status | What that means |
|---|---|---|
| Topical finasteride (sprays, gels, compounded solutions) | Compounded | The FDA states that no topical finasteride formulation is FDA-approved, and issued a safety alert about compounded versions in April 2025.[8] We cover the trial data and the alert in our oral vs topical guide. |
| Low-dose oral minoxidil | Off-label | Minoxidil tablets are approved for resistant high blood pressure and carry a boxed warning at those doses.[9] Using them for hair is off-label. |
| Dutasteride | Off-label | Approved in the US for prostate enlargement, not hair loss. One 917-man 24-week trial found dutasteride 0.5 mg beat finasteride 1 mg on hair count and thickness.[7] |
| Laser caps and combs | FDA-cleared | Cleared through the 510(k) route as similar to existing devices, which is a comparative standard rather than independent proof of effectiveness. |
| Supplements | Supplement | The FDA does not approve supplements before sale and their claims are not FDA-evaluated. |
We could not obtain full texts for several papers behind paywalls, so this article does not quote year three to five hair counts for finasteride, absolute per-group hair counts from the minoxidil trials, or absolute counts from the dutasteride comparison. Where a number is missing here, it is because we could not read it in a primary source, not because it does not exist.
Where to go next
- The Norwood and Ludwig scales — working out what stage you are actually at
- Side effects: what the data shows — rates from the label and the meta-analyses
- What treatment costs per year
- All our hair loss coverage
Frequently asked questions
Do finasteride and minoxidil work together?
They act on different things, so they are commonly prescribed together, and several telehealth services sell them as a bundle. We have not found a large head-to-head trial that isolates how much the combination adds over either drug alone, so we are not going to put a number on it. What is documented is that each one beat placebo in its own trials.
How long before I know if it is working?
The FDA-approved label for Women’s Rogaine 5% says results may occur at three months with once-daily use, and that some people need at least six months. The finasteride trials measured their primary outcomes at 12 and 24 months. Assessing either drug before three to six months is too early.
What happens if I stop?
For minoxidil, the FDA label is explicit: normal hair loss starts again and you will likely lose the new hair you grew within three to four months. Both drugs are treatments you continue, not courses you complete.
Is finasteride stronger than minoxidil?
They are not on the same scale, so the question does not have a clean answer. Finasteride acts on the hormone driving miniaturization; minoxidil acts on the follicle’s growth phase locally. Finasteride is oral and prescription-only; topical minoxidil is over the counter. Their trials used different outcome measures, so the numbers are not directly comparable.
Is dutasteride better than finasteride?
In one 917-man 24-week trial, dutasteride 0.5 mg beat finasteride 1 mg on hair count and hair thickness. But dutasteride is not FDA-approved for hair loss in the US – it is approved for prostate enlargement – so using it for hair is off-label, and that trial ran only 24 weeks.
Does DHT cause all hair loss?
No. The DHT mechanism describes pattern hair loss specifically. Shedding after illness, childbirth, stress or a nutritional problem is a different process, and treatments aimed at DHT are not the answer to it. That is why identifying what you actually have comes before choosing a treatment.
Sources
- U.S. Food and Drug Administration. PROPECIA (finasteride) tablets, prescribing information. 2022. accessdata.fda.gov
- Kaufman KD, Olsen EA, Whiting D, et al. Finasteride in the treatment of men with androgenetic alopecia. J Am Acad Dermatol. 1998;39(4 Pt 1):578-589. PMID 9777765.
- Kaufman KD, et al. Long-term (5-year) multinational experience with finasteride 1 mg in the treatment of men with androgenetic alopecia. Eur J Dermatol. 2002;12(1):38-49. PMID 11809594.
- U.S. Food and Drug Administration. Women’s ROGAINE 5% Minoxidil Topical Aerosol, Drug Facts label. 2019. accessdata.fda.gov
- U.S. Food and Drug Administration. Approval letter, NDA 021812/S-009. 28 February 2014. accessdata.fda.gov
- Olsen EA, Dunlap FE, Funicella T, et al. A randomized clinical trial of 5% topical minoxidil versus 2% topical minoxidil and placebo in the treatment of androgenetic alopecia in men. J Am Acad Dermatol. 2002;47(3):377-385. PMID 12196747.
- Gubelin Harcha W, Barboza Martinez J, Tsai TF, et al. A randomized, active- and placebo-controlled study of the efficacy and safety of different doses of dutasteride versus placebo and finasteride. J Am Acad Dermatol. 2014;70(3):489-498.e3. PMID 24411083.
- U.S. Food and Drug Administration. FDA alerts health care providers, compounders and consumers of potential risks associated with compounded topical finasteride products. 22 April 2025. fda.gov
- U.S. Food and Drug Administration. LONITEN (minoxidil) tablets, prescribing information. 2015. accessdata.fda.gov
Affiliate disclosure: this page contains affiliate links. We may earn a commission when you buy through them, at no additional cost to you. Commissions never determine what we cover or what the evidence sections say. Read our full affiliate disclosure.
How we researched this: every figure on this page is sourced to a numbered reference below. For this article those sources are FDA-approved drug labels and approval letters, an FDA safety communication, and published randomized controlled trials. Where a figure could not be verified from a primary source, we say so in the text rather than estimating. We do not test products and we do not practice medicine. See our review methodology.
