Spironolactone (Aldactone) for Hair Loss - How It Works, Effectiveness, Dosage & Side Effects
Last reviewed on 25 July 2026. We review our treatment guides every six months to keep them accurate.
Spironolactone, sold under the brand name Aldactone, is a prescription medicine that blocks the effects of androgens, the hormones that can contribute to hair thinning in women. It is licensed as a diuretic (a "water tablet") for conditions such as high blood pressure and heart failure, and it is used off-label for female pattern hair loss, also known as female androgenetic alopecia. This guide explains how spironolactone for hair loss works, the evidence behind it, typical dosing, how long it takes and the side effects to be aware of. It is written for general information only, so please speak to your doctor or another medical professional before starting or changing any treatment. You can also read the NHS spironolactone page and the British Association of Dermatologists leaflet.
What is Spironolactone?
Spironolactone is a potassium-sparing diuretic, also called an aldosterone antagonist. It is mainly used to treat high blood pressure, heart failure and fluid build-up, and it works in part by blocking aldosterone, a hormone that helps regulate the body's fluid and salt balance (NHS). In the context of hair loss, it is useful because it also has an anti-androgen effect, reducing the influence of the hormones that can shrink hair follicles and lead to thinning.
It is prescribed off-label for female pattern hair loss, particularly in women whose hair loss is linked to raised androgen levels or hormonal conditions such as polycystic ovary syndrome (PCOS). Our guide on PCOS and hair loss covers this in more detail. Rather than directly stimulating new growth, spironolactone works by addressing one of the underlying drivers, excess androgen activity. This makes it an option some doctors consider for women who have not responded well to first-line treatments such as minoxidil for women.
How Does Spironolactone Work for Hair Loss?
Spironolactone acts as an anti-androgen in two ways: it blocks androgen receptors so that hormones such as testosterone and dihydrotestosterone (DHT) cannot bind to them as easily, and it can also reduce the body's production of androgens (British Association of Dermatologists). In female pattern hair loss, these hormones drive the miniaturisation of hair follicles, gradually producing thinner, weaker strands.
DHT is one of the main contributors to androgenetic alopecia. When it binds to receptors in the hair follicle, it shortens the growth cycle and the follicle produces progressively finer, shorter hair. By lowering circulating androgens and limiting their effect at the follicle, spironolactone may slow this process and, in some women, support healthier growth (systematic review).
Who is Spironolactone Suitable For?
Spironolactone is generally prescribed to women with female pattern hair loss, or with hair loss and other symptoms linked to hormonal conditions such as PCOS. It is also used off-licence for acne and for hirsutism (excess facial and body hair) in women (BAD). It is not usually given to men for hair loss, because its anti-androgen action can cause feminising effects such as breast enlargement and tenderness (gynaecomastia) and reduced libido (NHS).
Women with excessive shedding, thinning across the top of the scalp, or diffuse hair loss linked to hormonal factors may be considered for spironolactone, especially where other treatments have not helped or blood tests suggest raised androgen levels. Your doctor is best placed to judge whether it is appropriate for you.
How Effective is Spironolactone for Hair Loss?
Spironolactone is used off-label in females and there are no large randomised controlled trials confirming its benefit for hair, so the evidence is limited and drawn mainly from smaller studies. A 2023 systematic review and meta-analysis found that around 57% of women treated with oral spironolactone saw an improvement in their hair loss. Improvement was more likely when it was combined with minoxidil (about 66%) than when spironolactone was used on its own (about 43%), although the studies varied considerably (Cureus systematic review). The British Association of Dermatologists also notes that, taken long term, spironolactone can reduce shedding and improve the thickness of scalp hair in women with certain types of hair loss (BAD), and a clinic case series of women with female pattern hair loss reported reduced shedding and stabilised or improved density in many patients (JAAD).
Results build slowly and the greatest benefits are usually seen in those who start earlier and keep treatment going consistently. Some women notice less shedding within a few months, while a fuller effect on density can take a year or more.
How Long Does It Take to See Results?
Spironolactone works gradually. For hair, treatment usually needs to be continued for up to six months before any benefit can be seen, and longer for changes in density to show (BAD). Consistency matters, and if treatment is stopped the benefit is generally lost over time and shedding may return. If you are wondering how long it takes for spironolactone to work for hair loss, the honest answer is several months at the very least, so patience is important.
Dosage and Treatment Plan
For skin and hair conditions the usual dose is between 50 mg and 200 mg a day, with higher doses typically needed for hair loss than for acne (BAD). Some doctors use lower doses, such as 25 mg, in combination with low-dose minoxidil, while doses up to around 200 mg a day may be used in more resistant cases, which can increase the chance of side effects (Cureus review). For hirsutism (unwanted facial hair), spironolactone is prescribed within this same 50 to 200 mg range. Exact dosing varies from person to person, so the right dose and any combination with other treatments, such as topical minoxidil or the contraceptive pill, should always be decided by your doctor.
Side Effects and Safety Considerations
Like any medicine, spironolactone can cause side effects. Commonly reported ones include:
Breast tenderness or enlargement
Irregular or changed menstrual periods
Increased urination (its diuretic effect)
Dizziness or light-headedness, particularly when standing up
Feeling tired or low in energy
Breast tenderness and menstrual changes often settle with continued treatment (BAD). Because spironolactone can raise the level of potassium in the blood, a condition called hyperkalaemia, your doctor may arrange a blood test to check your potassium before starting and occasionally during treatment. This is more important for women over 45 or those with heart or kidney problems (NHS).
Spironolactone is not recommended in pregnancy because it can affect the development of a baby's sex organs, particularly in a male fetus. If you are pregnant, think you might be, or are planning a pregnancy, speak to your doctor; it is usually considered safe to try to conceive about a month after stopping. It is also not suitable for people with severe kidney problems, Addison's disease or a history of high potassium levels (NHS).
Alternatives to Spironolactone
If spironolactone is not suitable, or causes side effects, your doctor may discuss other options, including:
Minoxidil: a topical (and sometimes oral) treatment that helps stimulate hair growth; you can compare the forms in our guide to topical versus oral minoxidil.
Finasteride: occasionally prescribed off-label for women, though less commonly than for men.
Low-level laser therapy (LLLT): a non-invasive option that may support regrowth in some people.
Platelet-rich plasma (PRP): PRP injections that may improve thickness and reduce shedding.
Frequently Asked Questions
Can spironolactone cause hair loss?
Spironolactone is a treatment for hair loss, not a cause of it. Some women notice a little extra shedding when starting any hair treatment as the growth cycle adjusts, but this is usually temporary and settles as new hairs come through. If you are experiencing ongoing or heavy hair loss, it is worth speaking to your doctor to check the underlying cause rather than assuming it is the medicine.
How long does it take for spironolactone to work for hair loss?
Treatment usually needs to be continued for up to six months before any benefit is visible, and improvements in density can take a year or longer. It works slowly, so consistency is important.
What are the side effects of spironolactone, including at 25 mg?
Even at lower doses such as 25 mg, possible side effects include breast tenderness, changes to your periods, increased urination and dizziness. Higher doses can make side effects more likely. Because spironolactone can raise potassium levels, your doctor may check your blood during treatment.
What dose of spironolactone is used for facial hair?
For hirsutism (excess facial hair), spironolactone is generally used within the same 50 to 200 mg per day range as for other skin and hair conditions, with the exact dose decided by your doctor. It works gradually over several months.
Can men take spironolactone for hair loss?
Spironolactone is not usually prescribed to men for hair loss because its anti-androgen effect can cause feminising side effects, such as breast enlargement (gynaecomastia). Men are more commonly offered other treatments, so speak to your doctor about the options.
Is spironolactone available on the NHS for hair loss?
Spironolactone is used off-label, which means it is not specifically licensed for hair loss, but it can still be prescribed on the NHS at a doctor's discretion. Whether it is offered will depend on your individual circumstances.
What happens if I stop taking spironolactone?
If you stop, any benefit is generally lost over time and shedding may gradually return, because the medicine controls rather than cures the process. Do not start or stop it without discussing it with your doctor.
Spironolactone can be a helpful option for some women whose hair loss is linked to hormonal factors. If you are considering it, speak to your doctor or a medical professional to discuss whether it is right for you.
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