Finasteride vs Spironolactone

Finasteride: A daily tablet that lowers DHT, the hormone behind male pattern hair loss. It is better at keeping the hair you still have than at bringing back hair that is gone. Spironolactone: A water tablet that blocks male-type hormones as a side effect. In adult women, that side effect is the reason it is prescribed for acne.

Reviewed by Dr. Schwarz, Board-Certified Dermatologist

Which one?At a glance What it treats Diagrams How you take it Results Side effects Safety Cost When you stop Questions

Which one is right for you?

Choose Finasteride if…

Choose to keep the hair you still have in male pattern hair loss — the best-studied tablet for it.

Thinning at the crown or hairline
You'll take it daily for at least a year to judge it
You want a cheap, once-daily tablet

Choose Spironolactone if…

Choose for hormonal acne in adult women as a long-term, low-cost alternative to repeated antibiotic courses.

Adult woman with jawline or cyclical acne
Acne returns after antibiotics
Reliable contraception in place

Use care together

Can you take them together?

Both lower hormone effects and are sometimes combined for female hair loss under specialist care. Both must be avoided in pregnancy.

At a glance

● Finasteride

● Spironolactone

Type

DHT blocker (5-alpha reductase inhibitor)

Hormone-blocking water tablet

What it does

Lowers DHT, the hormone behind male pattern hair loss

Blocks male-type hormones that drive oil

Best for

Male pattern hair loss

Hormonal acne in adult women

Prescription

Yes

Form

Tablet, 1 mg

Tablet

How often

Once daily

Once or twice daily

Course length

Ongoing

Time to results

3–6 months; judge at 12

About 3 months

Main side effect

Sexual side effects in a few people

Passing more urine; irregular periods

Blood tests

None; PSA reads lower

Sometimes

Pregnancy

Never handle broken tablets

Avoid

Cost

Low; generic available

What it treats

Compare uses by strength of evidence. Evidence level describes confidence in a benefit, not its size.

Evidence level

Finasteride

Spironolactone

Strong evidenceMost established uses

AI-generated educational illustration: Crown hair thinning with hair retained around the sides on a light scalp.

Male Pattern Hair Loss

Stops loss in most men and regrows some.

Acne

Reduces hormonal breakouts in women.

Moderate evidenceSome supportive research

—

Hirsutism

Slows unwanted hair growth.

Limited evidenceEarly or small studies

A widened center part with thinning hair on the scalp.

Female Pattern Hair Loss

Used after menopause in some cases.

Female Pattern Hair Loss

May slow thinning.

Not effective

Alopecia Areata

Doesn't act on immune hair loss.

diffuse reduced hair density across the scalp with the frontal hairline retained on light skin.

Telogen Effluvium

Shedding has a different cause.

Male Pattern Hair Loss

Not used in men due to side effects.

How it works

Finasteride mechanism diagram. Reduces DHT production: Blocks 5-alpha reductase, which converts testosterone to DHT. Slows follicle shrinkage: Less DHT reduces the signal that miniaturizes susceptible follicles. Supports hair growth: More hairs enter the growing phase over time. — Open full-size diagram
Diagram explanation and sources
Reduces DHT production: Blocks 5-alpha reductase, which converts testosterone to DHT. Slows follicle shrinkage: Less DHT reduces the signal that miniaturizes susceptible follicles. Supports hair growth: More hairs enter the growing phase over time.
Oral finasteride for androgenetic scalp hair loss. The main target shown is type II 5-alpha reductase. Finasteride reduces DHT production; it does not block androgen receptors. The larger follicle is a conceptual illustration of growth support, not a guaranteed transformation or creation of new follicles.
Source 1 · Source 2 · Source 3

Spironolactone mechanism diagram. Reduces breakouts: Hormone-driven acne gradually improves. Makes less oil: Oil glands release less sebum into follicles. Blocks androgen signals: Limits hormone stimulation of oil-gland cells. — Open full-size diagram
Diagram explanation and sources
Reduces breakouts: Hormone-driven acne gradually improves. Makes less oil: Oil glands release less sebum into follicles. Blocks androgen signals: Limits hormone stimulation of oil-gland cells.
Oral spironolactone acne mechanism overview. Clinical evidence for acne improvement and reduced sebum is complemented by topical receptor studies and cultured sebocyte findings. The receptor is conceptual and intracellular; hormone shapes and oil droplets are not to scale. This is not a direct exfoliant or antibacterial.
Source 1 · Source 2 · Source 3 · Source 4

How you take it

Treatment plan

The dose does not change with weight, and there is no build-up period. What varies is how often people take it.

Starting dose: 1 mg once a day from day one. Nothing to titrate.

Going up: Nowhere useful to go. Higher doses lower DHT a little further without growing more hair, and the 5 mg prostate dose is not a better hair drug.

Going down: Some doctors use 1 mg every other day, or a few days a week, when side effects are the worry. A reasonable compromise on thinner evidence.

Total course: Open-ended. The effect lasts only as long as you keep taking it.

The dose depends on tolerance and blood pressure more than weight. Kidney function sets the ceiling.

Starting dose: Often 25 mg to 50 mg daily, to see how blood pressure and the bladder respond.
Going up: Increased every four to six weeks if tolerated and acne has not responded.
Usual dose: Most settle between 50 mg and 100 mg a day. Higher doses are used, but side effects rise with them.
Total course: No set course. Many women stay on it for years, and stopping too early is the usual reason acne returns.

When to take it

Any time of day, with or without food. Attach it to something you already do — two weeks of forgetting is what ruins this drug, not a bad day. Do not split or crush the 1 mg tablet.

Once daily, with or without food, though food reduces nausea. Take it in the morning — it increases urination for the first week or two. Some doctors split the dose. Drink to thirst; forcing water on a diuretic just means more trips to the bathroom.

If you miss a dose

Take it when you remember, or skip it. Never take two at once. One missed tablet makes no difference. A missed month does.

Take it when you remember, the same day. If it is nearly the next day, skip it.

Monitoring

No routine blood tests are needed for a healthy man taking 1 mg for hair loss. The honest monitoring is photographs — same spot, same light, every few months, because slow change is invisible day to day.

One number does change. Finasteride roughly halves PSA, the prostate blood test. It does not hide a problem, but the result has to be read knowing you are on it, so tell any doctor who orders one. Nothing needs checking on a schedule; the recurring question is whether you still want to take it.

Blood pressure is checked before starting. For healthy women under about 45 with normal kidneys and no interacting medicines, current guidance supports skipping routine repeated potassium tests — abnormal results in this group are rare and rarely meaningful. Potassium and kidney function are checked over 45, with kidney or heart disease, or on drugs that raise potassium.

This is a drug people stay on for years. What drifts is kidney function with age and the medicine list, so the decision gets revisited. A yearly review of dose, blood pressure and other medicines is usual.

When you’ll see results

Approximate windows, not promises.

● Finasteride

● Spironolactone

Months 1 to 3

Months 1 to 3Starting: Nothing visible. Some men shed more at first as short, weak hairs are replaced. Uncomfortable to watch, and it settles.

Months 3 to 6

Months 3 to 6Turning: Shedding slows, and a lower shed rate is often the first sign it is working. Hair feels thicker in the hand before it looks thicker. Sexual side effects, if they happen, show up here.

Months 6 to 12

Months 6 to 12Regrowth: Regrowth appears if it is going to, mostly at the crown and mid-scalp, fine at first and then thickening. Nearly all measured regrowth happens here.

After 12 months

After 12 monthsJudge it here: If your hair has simply held, that is a result — holding is what this drug does best. Trials counted more hairs at one year on the drug and fewer on placebo — part of the difference is loss that did not happen.

Weeks 1 to 2

Weeks 1 to 2More urination, sometimes mild lightheadedness on standing. Skin unchanged.

Weeks 2 to 8

Weeks 2 to 8Oiliness drops. Periods may become irregular at higher doses.

After 12 weeks

After 12 weeksThe fair judgment point. Improvement often continues to six months, so a partial response at three months means continue, not stop.

Side effects

Sorted by what to do about them.

Finasteride

Spironolactone

Common

Lower sex drive or erection problems (a few percent)
Less ejaculate

Common

Passing more urine; thirst
Irregular periods or spotting
Breast tenderness; dizziness on standing

Tell your doctor

Breast tenderness or a lump
Low mood

Tell your doctor

Muscle cramps or weakness

Stop and get care

Swelling of face or throat

Stop and get care

Irregular heartbeat or severe weakness (high potassium)

Safety and who should avoid it

Pregnancy

Never

Anyone pregnant must not handle broken tablets.

Avoid

Reliable contraception is expected.

Breastfeeding

Never

Not for women who could become pregnant.

Ask first

Generally considered compatible; discuss.

Children

Not used

Adults only.

Teens

Used in older teens.

Monitoring

Use care

Tell your doctor before a PSA test — it halves the reading.

Sometimes

Potassium if over 45 or with kidney disease.

Key interactions

None important

—

Check

Potassium supplements, ACE inhibitors, some blood pressure drugs.

Other cautions

Discuss

Any history of depression.

Avoid

Kidney disease; not used for acne in men.

Cost and getting it

Getting it and cost

Generic finasteride 1 mg is inexpensive and widely stocked — one of the cheaper long-term prescriptions in dermatology. Branded Propecia costs considerably more for the same drug.

Telehealth subscriptions bundle the tablet with shipping and a consultation — convenient, and usually more per month than a local generic. Insurance often does not cover it, because hair loss counts as cosmetic, so most people pay cash.

Generic spironolactone is cheap and widely available. Some insurers query acne as an off-label use, but the cost rarely blocks treatment. The liquid form costs far more than tablets.

When you stop

Comes back?

Yes. Gains are lost over about 12 months after stopping.

Acne often returns within months of stopping.

Taper needed?

No.

After the last dose

Wait a month before donating blood.

Periods regulate within a cycle or two.

Common questions

Finasteride:How long before I know if it is working?

Six months for the first honest look, twelve for the verdict. Photographs make that possible.

Finasteride:Do I have to take it forever?

As long as you want the effect. Stopping puts you back on your old path within six to twelve months.

Finasteride:Are the sexual side effects permanent?

For almost everyone they do not happen or they resolve. A minority report symptoms that persisted after stopping, and research has neither confirmed nor ruled that out. Worth discussing before you start.

Finasteride:Can my partner touch the tablets?

Whole, coated tablets are fine. Broken or crushed ones should not be touched by anyone pregnant or who could become pregnant.

Finasteride:Is my hair falling out more since I started?

It can, in the first weeks, as weak short hairs are replaced. It usually settles by month three. Still climbing at four months, get it looked at.

Finasteride:Can I take it with minoxidil?

Yes, a common pairing. They work on different parts of the problem, so the effects add up.

Spironolactone:Do I need regular blood tests?

A healthy woman under about 45 with normal kidneys and no interacting medicines does not need routine potassium testing. If you are older, or have kidney or heart disease, or take drugs that raise potassium, testing is appropriate.

Spironolactone:Do my hormone levels have to be abnormal for it to work?

No. Most women who respond have normal blood tests. What matters is oil gland sensitivity, which is not measurable.

Spironolactone:Will it stop my periods?

It can make them irregular at higher doses. A combined contraceptive pill alongside usually prevents this.

Spironolactone:Can men take it for acne?

Generally avoided — at acne doses it commonly causes breast enlargement and tenderness. Clascoterone cream is the alternative.

Spironolactone:What about the old cancer warning?

Those findings came from rats on very high doses. Human studies have not shown a matching risk at acne doses.

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