Spironolactone for Acne: Evidence, Side Effects & What to Ask

Spironolactone is a prescription pill that dermatologists use off-label for acne in adult women, and it now has a solid randomized trial behind it. In the UK’s SAFA trial, women taking it reported clearer skin and better acne-related quality of life than those on placebo, with the difference growing by 24 weeks. The 2024 American Academy of Dermatology (AAD) guideline gives it a conditional recommendation. It isn’t safe in pregnancy and it isn’t for everyone, so it’s a conversation to have with a clinician. This page is meant to help you have that conversation.

What is spironolactone, and how does it work on acne?

Spironolactone was developed as a blood-pressure and fluid-retention drug. Its official US label (Aldactone prescribing information) lists heart failure, high blood pressure, fluid buildup and a hormone condition called primary hyperaldosteronism. Acne isn’t on the list, so using it for acne is “off-label,” which is common and legal but worth knowing.

For acne, what matters is its anti-androgen effect. Androgens (hormones such as testosterone) drive oil production. According to StatPearls (NCBI Bookshelf), spironolactone “may reduce sebum production by blocking the binding of dihydrotestosterone to its androgen receptors,” and it also lowers testosterone production. StatPearls describes it as an alternative for “adult females with persistent and/or late-onset acne,” the pattern I cover in hormonal acne in adults. The AAD notes dermatologists have prescribed it for acne for many years, and that it isn’t prescribed for acne in men because of side effects; StatPearls notes that in men these include breast enlargement (gynecomastia) and loss of libido.

What did the SAFA trial find?

For years, spironolactone’s use for acne rested mostly on experience and small studies. That changed with SAFA, published in the BMJ in 2023. It was a pragmatic, double-blind, placebo-controlled trial run across England and Wales. It enrolled 410 women aged 18 or older who’d had facial acne for at least six months, bad enough that a clinician would consider oral antibiotics. Participants took 50 mg a day of spironolactone or a matching placebo for six weeks, then 100 mg a day up to week 24, and could keep using topical treatments. Their average age was 29.

Here’s what the published results showed:

The authors concluded that spironolactone “improved outcomes compared with placebo, with greater differences at week 24 than week 12,” and called it “a useful alternative to oral antibiotics for women with acne.” That matters because guidelines are trying to cut antibiotic use; the AAD guideline recommends “limiting systemic antibiotic use.”

A few honest caveats. The week-12 difference was modest, so this is a slow-burn treatment; most of the benefit showed up by six months. Even with it, only about one in five women met the strict clinician-rated “success” definition at week 12. And the trial population was mostly white (7% of participants were from other ethnic groups), so we know less about how it performs in other groups.

What does the 2024 AAD guideline say?

The 2024 AAD acne guideline (Reynolds et al., JAAD) lists spironolactone among its conditional recommendations, while benzoyl peroxide, topical retinoids, topical antibiotics and oral doxycycline get strong ones. The AAD’s announcement describes hormonal therapies such as spironolactone as conditionally recommended “to address hormonal causes of acne.” A conditional recommendation means it’s a good option for some people, and the choice should depend on your situation and preferences. That’s exactly why it belongs in a conversation with your clinician rather than a one-size-fits-all rule.

What are the side effects?

The AAD lists common side effects as painful periods, irregular periods, breast tenderness and breast enlargement, with fatigue, headache and dizziness less common. It adds that these may decrease when spironolactone is combined with a birth control pill. The FDA label also lists irregular or absent periods, breast pain and dizziness. In SAFA, headaches were the side effect that stood out.

What about cancer? You may have read about a tumor warning. The AAD says that although warnings arose from animal studies, the evidence in humans doesn’t support an increased risk of breast cancer. A 2022 meta-analysis in JAMA Dermatology of seven studies found no meaningful association between spironolactone and breast cancer, though its authors noted the certainty of evidence was low. The current Aldactone label carries no boxed warning.

Is spironolactone safe in pregnancy?

No. The AAD lists spironolactone among acne treatments that “can cause serious birth defects.” The FDA label explains that, based on its mechanism and animal studies, it “may affect sex differentiation of the male during embryogenesis.” The AAD’s spironolactone page says birth control is essential while taking it. If you’re breastfeeding, the label notes an active breakdown product has been found in breast milk in low amounts, so discuss it with your clinician.

Do you need potassium blood tests?

This is where advice genuinely varies. Spironolactone can raise blood potassium (hyperkalemia), and the label says that risk is higher with kidney problems, potassium supplements, potassium-containing salt substitutes, or drugs that raise potassium, such as ACE inhibitors and angiotensin receptor blockers.

But in healthy young women, the risk looks very low. A 2015 JAMA Dermatology study of 974 healthy young women taking spironolactone for acne found just 13 abnormal results among 1,802 potassium tests (0.72%), about the same as the background rate of 0.76%, and 6 of those 13 were normal on retesting. The authors concluded routine potassium monitoring is unnecessary for healthy young women on spironolactone for acne. A smaller 2019 study suggested age may matter: hyperkalemia occurred in 2 of 12 women aged 46 to 65, compared with 1 of 112 women aged 18 to 45.

In practice, some clinicians check potassium and kidney function at the start and some don’t. StatPearls advises routine blood work, and the AAD patient page says blood tests are needed before starting and advises skipping coconut water and potassium supplements. Your age, kidney health and other medicines should decide what’s right for you.

What to ask your clinician about spironolactone

1. Is my acne a good fit? For example, persistent adult acne that hasn’t responded well to topical treatments.
2. What dose will I start on, and how long before we judge it? SAFA used 50 mg then 100 mg a day, and the clearest benefit appeared around 24 weeks.
3. Do I need blood tests? Ask whether your age, kidney function or other medications change the answer.
4. Which of my medicines or supplements interact? Mention blood pressure drugs, potassium supplements, salt substitutes, and anything else you take.
5. What contraception should I use, and should spironolactone be combined with a birth control pill?
6. What should I keep using on my skin? Spironolactone works best as part of a plan; see my adult hormonal acne routine for the topical side.
7. What’s the plan if I want to get pregnant?

For realistic timelines across treatments, see how long acne treatments take.

Frequently asked questions