Spironolactone for acne: what the evidence shows

Spironolactone is a generic blood pressure and heart failure pill that clinicians prescribe off-label for hormonal acne in adult women. It isn’t FDA-approved for acne. The best evidence comes from SAFA, a 2023 trial of 410 women, in which 82% on spironolactone reported their acne had improved after 24 weeks, against 63% on placebo. Here is what the trial found, how the drug is dosed, who should avoid it and what it costs online as of October 18, 2026.

How spironolactone works on acne

Spironolactone’s label describes it as an aldosterone antagonist, approved for heart failure, high blood pressure, edema from cirrhosis or kidney disease, and primary hyperaldosteronism (label). The same label notes its anti-androgenic properties: it blocks some of the effects of male-type hormones. That anti-androgen effect is the reason it is used for acne in women.

The SAFA trial tested it specifically as an alternative to oral antibiotics for women whose acne was bad enough to warrant them (Santer et al.).

What the SAFA trial found

SAFA was a double-blind, placebo-controlled phase 3 trial run across England and Wales and published in the BMJ in 2023. It enrolled 410 women aged 18 and over who had had facial acne for at least six months; their average age was 29. Women could keep using topical treatments.

Three things stand out. The benefit grew with time: the gap in self-reported improvement was small and not significant at 12 weeks, and clear at 24. Investigators, who rated skin without knowing the treatment, judged spironolactone a success three times as often at 12 weeks. And there were no serious adverse reactions, though headaches were more common.

The authors concluded that spironolactone “is a useful alternative to oral antibiotics for women with acne.”

Spironolactone or an oral antibiotic?

SAFA was built around a real choice. Every woman in it had acne that her clinician judged bad enough for oral antibiotics, the usual next step after creams. Spironolactone beat placebo on the trial’s quality-of-life score at 12 weeks (an adjusted difference of 1.27 points on a 30-point scale) and by more at 24 weeks (3.45 points), and the authors called it a useful alternative to antibiotics. The trial didn’t compare spironolactone with an antibiotic directly, so it can’t say which works better, only that spironolactone works.

Questions to ask before you start

• Could I become pregnant while taking it, and what contraception should I use?
• Do my kidneys, blood pressure or other medicines make high potassium more likely?
• Do I take potassium supplements, salt substitutes, an ACE inhibitor or an ARB?
• Will you check my potassium, and when?
• What topical should I keep using alongside it, and when will we judge whether it’s working?

Dose and how long it takes

In SAFA, women took 50 mg a day for the first six weeks, then 100 mg a day until week 24. Your prescriber sets your own dose.

Plan on about six months to judge it. SAFA’s own numbers show most of the difference from placebo arriving between week 12 and week 24. In SAFA, participants could keep using their topical treatments, and the online providers that prescribe spironolactone also sell topicals such as tretinoin, azelaic acid and clindamycin.

Side effects and who should avoid it

Spironolactone has no boxed warning on its current label, but it has real precautions.

• Pregnancy. Avoid it. The label says spironolactone may affect the sexual development of a male fetus, based on how it works and on animal studies, and advises avoiding it in pregnant women.
• High potassium. It can raise potassium. The label contraindicates it in people with high potassium, Addison’s disease or who take eplerenone, and says to check potassium within a week of starting and regularly after. The risk rises with kidney problems, potassium supplements, salt substitutes and drugs such as ACE inhibitors and ARBs.
• Blood pressure and kidneys. As a diuretic, it can cause dehydration, low blood pressure and worse kidney function, especially with other drugs that do the same.
• Hormonal effects. The label lists irregular periods or no periods, breast and nipple pain and, in men, breast enlargement.
• Everyday effects. Dizziness, headache, tiredness, nausea and leg cramps are among the reactions listed.

Tell the prescriber about every medicine and supplement you take, and whether you could become pregnant. See our spironolactone for acne medication guide for the full label summary.

Topical spironolactone

Some providers sell spironolactone as a cream or gel. Wisp lists a topical spironolactone for acne from $39 a month for 3 months. Topical versions are compounded by a pharmacy and are not FDA-approved; the FDA doesn’t review compounded drugs for safety, effectiveness or quality (FDA). SAFA tested tablets, so its results don’t tell you how a topical version performs.

Getting spironolactone online and what it costs

Spironolactone is generic and cheap. These are the prices online providers list, read on October 18, 2026:

Scroll sideways to see the full table

Nurx bills the tablets for 3 months at a time, and Wisp sells its oral spironolactone as a one-time order or a subscription. Nurx also takes insurance for prescriptions, which can bring the tablets to $0, though its $40 consult isn’t billed to insurance. Both providers offer other acne treatments in the same account: Nurx lists clindamycin solution at $20 a month and tretinoin at $30, and Wisp lists generic tretinoin from $28.

For more options, see our ranking of the best online acne treatment, or the full online prescription skin care list.

Is spironolactone right for you?

It is worth asking about if you are an adult woman with acne that hasn’t cleared on topicals, or if you’d rather avoid long courses of oral antibiotics, which is the comparison SAFA was designed around. It is not a fit if you are pregnant or trying to be, have kidney problems or high potassium, or take medicines that raise potassium. A clinician will weigh those against the benefit.

The bottom line

Spironolactone is an off-label but well-studied option for women with acne: in the SAFA trial, 82% reported improvement at 24 weeks, against 63% on placebo, with no serious adverse reactions. It takes months to work, must be avoided in pregnancy and can raise potassium. Generic tablets cost $15 a month at Nurx plus a $40 consult, as of October 2026. Start at our skin care hub to compare providers.