Oral finasteride 1 mg for male pattern hair loss
Finasteride is a daily tablet that lowers dihydrotestosterone (DHT), the hormone that shrinks hair follicles in men with genetic hair loss. It is FDA-approved for male pattern hair loss in men only. It slows loss and regrows some hair for many men, it has real side effects that deserve a straight conversation, and it works only while you keep taking it.
Information current as of November 10, 2026. Educational only. Confirm everything here with your own clinician before starting, stopping or changing any medication.
At a glance
Drug class
5-alpha-reductase inhibitor. It blocks the enzyme that turns testosterone into DHT.
How it is taken
One 1 mg tablet by mouth once daily, with or without food. The label says daily use for three months or more is needed before any benefit shows.
Approval status
FDA-approved (Propecia and generics) for male pattern hair loss in men. Dutasteride for hair loss is off-label.
Who it is for
Adult men with pattern thinning at the crown or mid-scalp who want to slow loss. It is not for women or children.
Main cautions
Sexual side effects, reports of depression and suicidal thoughts, lower PSA readings, and risk to a male fetus if a pregnant woman handles crushed tablets.
What it is
How finasteride works on a balding scalp
Male pattern hair loss runs in families. In men who carry the genes, scalp follicles are sensitive to DHT. DHT shortens each growth cycle, and the hair that grows back is thinner and shorter each time. This is called miniaturization.
Finasteride blocks type II 5-alpha-reductase, the enzyme that converts testosterone to DHT. Less DHT in the scalp means less miniaturization. Finasteride lowers both serum and scalp DHT (Kaufman 1998). It does not remove the underlying genetic tendency. If you stop, DHT comes back and the thinning resumes.
The label limits the approval to male pattern hair loss in men, and it says efficacy in bitemporal recession (the temples) has not been established. Finasteride also does not treat the shedding some people see after rapid weight loss or illness. That is a different process; we cover it in our post on hair loss and GLP-1 medicines.
Who it is for
Who is a fit, and who is not
The usual candidate is an adult man with a family pattern of thinning at the crown or the front and mid-scalp. A physician should confirm the pattern first, because thyroid disease, low iron, scalp conditions and some medicines also thin hair.
- Not for women who are or may become pregnant. The label contraindicates it in that group, and it is not indicated for women at all.
- Not for children.
- Not for anyone allergic to finasteride.
- Use extra thought if you have had depression, anxiety or a sexual problem in the past, if you are trying to conceive, or if you are over 40 and have not had a PSA check.
The adult dose on the label is 1 mg once daily. Taking more does not work faster; the patient leaflet says so directly. Topical finasteride products are not FDA-approved, and we use the oral tablet.
The evidence
What the trials show, with the numbers
The key trials ran for one to two years in young men. Two 1-year studies enrolled 1,553 men aged 18 to 41 with vertex hair loss, comparing finasteride 1 mg with placebo (Kaufman 1998). Of those, 1,215 men continued double-blind for a second year. Counted in a 1-inch circle of balding crown (baseline about 876 hairs), men on finasteride had 107 more hairs than placebo at one year and 138 more at two years. Men on placebo kept losing hair.
The label describes three 12-month studies in 1,879 men and a five-year extension. Only 323 men on finasteride and 23 on placebo reached year five, so the long-term data are thinner than the headline numbers suggest.
A network meta-analysis of 23 studies found that finasteride 1 mg grew less total hair at 24 weeks than dutasteride 0.5 mg, and less terminal hair than oral minoxidil 5 mg (Gupta 2022). Those were indirect comparisons across different trials, so treat them as a rough guide.
What this means in practice
Most men on finasteride slow or stop their loss, and some regrow hair, mainly at the crown. Results vary, the effect is gradual, and nobody can promise how much hair you will keep or regain.
Side effects
Sexual side effects
The label reports drug-related sexual side effects in year one of the hair loss trials. Decreased libido was 1.8% on finasteride versus 1.3% on placebo. Erectile dysfunction was 1.3% versus 0.7%. Ejaculation disorder was 1.2% versus 0.7%. Pooled, 3.8% of 945 men on finasteride reported at least one, against 2.1% of 934 on placebo. Most of these resolved after stopping, and in most men who kept going; the label says new reports fell to 0.3% or less by year five.
Treat that with caution. A 2015 review of 34 finasteride hair loss trials found none with adequate safety reporting. In 26 of 34 the safety follow-up lasted a year or less, and only 31% of 5,704 men prescribed low-dose finasteride in one health system would have qualified for the pivotal trials (Belknap 2015). Real-world rates may be higher than the trial table.
If you notice any change in erections, libido or ejaculation, tell your physician early. Erectile function has its own treatments; see our tadalafil page.
Side effects
Mood changes and post-finasteride syndrome
The current label lists depression and suicidal ideation and behavior among postmarketing reports. It also lists sexual dysfunction that continued after treatment was stopped, including erectile, libido, ejaculation and orgasm problems. The label says these were reported voluntarily from a population of uncertain size, so their frequency and a causal link cannot be established.
Some men and some researchers use the name post-finasteride syndrome for persistent sexual, mood and sleep symptoms after stopping. It is not an established diagnosis, and how often it occurs is not known. A small case series of six men who died by suicide after taking finasteride found a common pattern of insomnia and persistent sexual dysfunction, and its authors say it cannot prove causation (Irwig 2020).
I take these reports seriously because the harm can be severe and the trial safety data are weak. I will not tell you the syndrome is common either, because nobody knows that. Know the warning signs: new low mood, loss of interest, poor sleep, or a sexual change that bothers you. Stop the tablet and contact me. If you ever have thoughts of harming yourself, call or text 988 or go to an emergency department.
Other reported effects include breast tenderness or enlargement, testicular pain, and reduced semen quality that has improved after stopping. Tell your physician about any breast lump, pain or nipple discharge.
Monitoring
PSA, prostate screening and labs
Finasteride lowers PSA, the blood marker used to screen for prostate cancer. In the hair loss studies in men 18 to 41, mean PSA fell from 0.7 to 0.5 ng/mL at 12 months. In older men on the 5 mg dose for prostate enlargement, PSA falls by about half. In the Prostate Cancer Prevention Trial, the adjustment needed to keep PSA readings comparable rose from about 2 at two years to 2.5 at seven years (Etzioni 2005).
In practice, physicians usually double a PSA value after about six months on finasteride when reading it against normal ranges. The label adds a more important rule: any confirmed rise from your lowest value should be evaluated, even if the number is still in the normal range. Tell every clinician who orders PSA that you take finasteride.
The 5 mg prostate dose also raised the rate of higher-grade prostate cancer in one large trial (Gleason 8 to 10 in 1.8% vs 1.1%), and the label carries that warning for the class. For men starting at 40 or older, a baseline PSA is reasonable.
Safety at home
Pregnancy and handling the tablets
Women who are or may be pregnant
- Finasteride can cause abnormalities of the external genitalia in a male fetus.
- Coated, whole tablets block contact with the drug during normal handling.
- Women who are or may be pregnant should not handle crushed or broken tablets.
- Keep the bottle where a partner or child cannot get to it.
If you and your partner are trying to conceive, raise it before you start. The label notes that semen quality has improved after stopping in men who had poor quality on the drug, so this is a decision to make with your physician.
Timeline
How long to try it, and what happens when you stop
The label says daily use for three months or more is needed before benefit is seen. Most trials judged results at 12 months. I set expectations for a full year, with reviews at six and twelve months. If thinning continues despite steady use, finasteride is not working for you and we talk about other steps.
The label also says continued use is needed to sustain benefit, and that withdrawal reverses the effect within 12 months. This is a long-term decision, not a course. Plan to take it for as long as you want to keep the hair it holds.
Off-label option
Dutasteride
Dutasteride blocks both type I and type II 5-alpha-reductase. In the US it is approved for prostate enlargement, not hair loss, so using it for hair is off-label and the physician decides. In a 24-week trial of 416 men, dutasteride 2.5 mg grew more hair than finasteride 5 mg at 12 and 24 weeks (Olsen 2006). A later network meta-analysis found 0.5 mg of dutasteride grew more total hair than finasteride 1 mg at 24 weeks. Dutasteride carries the same class warnings: sexual effects, mood reports, lower PSA and pregnancy risk.
Related
Finasteride and testosterone therapy
Testosterone is the raw material for DHT. In men who are prone to pattern hair loss, taking testosterone can speed thinning, as we say on our men’s testosterone page. For that reason, hair is worth discussing before you start testosterone. Finasteride lowers DHT, which is why some men use the two together, but that combination has little trial data, and both hair and sexual function still need watching. If you are on both, your PSA readings need the finasteride adjustment above. Our post on low testosterone and TRT covers the rest of that decision.
Summit’s role
What Summit does with finasteride
Summit Men includes oral finasteride or minoxidil, with labs, for men who are a fit. The physician evaluation comes first. Dr. Miranda reviews your history, medicines, sexual and mood history, and labs, then decides whether finasteride, minoxidil or neither suits you.
- Summit is telehealth only. We prescribe the oral tablet; we do not offer topical finasteride.
- Dutasteride is off-label, and Dr. Miranda decides if it makes sense.
- We will not prescribe it to women who are or may become pregnant.
- Costs are on our pricing page. Individual results vary.
Common questions
Questions people ask
Is finasteride FDA-approved for hair loss?
Yes. The 1 mg tablet (Propecia and generics) is FDA-approved for male pattern hair loss in men only. It is not indicated for women. Using it in women is off-label and not appropriate for anyone who is or may become pregnant.
Does finasteride cause erectile dysfunction?
In the label’s year-one trial data, erectile dysfunction was reported by 1.3% of men on finasteride versus 0.7% on placebo. Libido and ejaculation problems were also slightly more common. The label also lists sexual problems that continued after stopping, with an unknown frequency. Tell your physician if you notice a change.
Can finasteride cause depression?
The label lists depression, suicidal ideation and behavior among postmarketing reports. A causal link and the rate are not established. If your mood drops or you sleep poorly after starting, stop the tablet and contact your physician. In a crisis, call or text 988.
Will finasteride affect my PSA test?
Yes. It lowers PSA. Physicians usually double the value after about six months on the drug when they interpret it. Any confirmed rise from your lowest number should be checked, even if it is still in the normal range.
What happens when I stop?
The label says the effect reverses within 12 months of stopping. The hair that finasteride was holding is gradually lost again. Some men have sexual or mood symptoms that last after stopping; tell your physician if that happens.
Sources
Where this comes from
All retrieved November 10, 2026.
- Organon. PROPECIA (finasteride) tablet, prescribing information. DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6f904709-65aa-44ce-b144-b4c8a0416e36
- Kaufman KD, et al. Finasteride in the treatment of men with androgenetic alopecia. J Am Acad Dermatol 1998. https://pubmed.ncbi.nlm.nih.gov/9777765/
- Olsen EA, et al. The importance of dual 5alpha-reductase inhibition in the treatment of male pattern hair loss: dutasteride versus finasteride. J Am Acad Dermatol 2006. https://pubmed.ncbi.nlm.nih.gov/17110217/
- Gupta AK, et al. Relative efficacy of minoxidil and the 5-alpha reductase inhibitors in androgenetic alopecia treatment of male patients: a network meta-analysis. JAMA Dermatol 2022. https://pubmed.ncbi.nlm.nih.gov/35107565/
- Belknap SM, et al. Adverse event reporting in clinical trials of finasteride for androgenic alopecia: a meta-analysis. JAMA Dermatol 2015. https://pubmed.ncbi.nlm.nih.gov/25830296/
- Irwig MS. Finasteride and suicide: a postmarketing case series. Dermatology 2020. https://pubmed.ncbi.nlm.nih.gov/31935720/
- Etzioni RD, et al. Long-term effects of finasteride on prostate specific antigen levels: results from the Prostate Cancer Prevention Trial. J Urol 2005. https://pubmed.ncbi.nlm.nih.gov/16093979/
Confirm with your provider. This page is general education, not medical advice, and it does not diagnose or treat anything. Every medication carries risks and is not right for everyone. Medication is prescribed only after a physician evaluation determines it is appropriate for you. Individual results vary and no outcome is guaranteed. Information current as of November 10, 2026.
Next step
Thinning hair and want a physician’s opinion?
Apply and Dr. Miranda will review your history and labs first, then tell you honestly whether finasteride, minoxidil or neither is a fit.