DHT Blockers for Women: What the Evidence Actually Shows
Last reviewed on 10 July 2026. We review our treatment guides every six months to keep them accurate.
DHT blockers are a group of treatments that lower dihydrotestosterone (DHT) or block its effect. In men they are a mainstay of pattern hair loss treatment. In women the picture is very different and far less settled, and the safety considerations carry more weight. This guide explains what DHT blockers are, what the evidence in women actually shows, and the safety points that matter most, particularly for anyone who is or could become pregnant. It is general information rather than medical advice, so please speak to a doctor or dermatologist about your own situation.
For an independently maintained overview of female pattern hair loss and the treatments used for it, the British Association of Dermatologists' patient information on female pattern hair loss is a good starting point. It is reviewed and updated periodically, so it stays current between our own reviews.
Dihydrotestosterone (DHT) is a hormone made from testosterone. In people who are genetically susceptible, it binds to receptors in scalp hair follicles and gradually shrinks them, a process called miniaturisation, so the hairs they produce become finer and shorter over time. This is well established in male pattern hair loss. In women it is less clear-cut: the role of androgens in female pattern hair loss has been clearly demonstrated only in men and is assumed rather than proven in women, and many women with female pattern hair loss have entirely normal androgen levels. That uncertainty is the reason blocking DHT is not a straightforward answer for women, as the rest of this guide explains.
Which treatments block DHT, and which do not
Not everything used for female hair loss is a DHT blocker, and on a page about DHT blockers the distinction matters.
The true DHT blockers are the 5-alpha-reductase inhibitors: finasteride and dutasteride. They block the enzyme 5-alpha reductase, which converts testosterone into DHT, and so lower DHT levels. As a guide to how much, finasteride 1mg a day lowers DHT in the blood by roughly 70 per cent, though that figure comes from studies in men.
Spironolactone and cyproterone acetate are not DHT blockers. They are anti-androgens that work in a different way, mainly by blocking the androgen receptor so that androgens have less effect, and in the case of cyproterone by also reducing androgen production. This is worth being clear about, because spironolactone is in fact the anti-androgen most often used for female hair loss in UK practice, yet it does not lower DHT in the way a 5-alpha-reductase inhibitor does.
Minoxidil is not a DHT blocker either. It is a hair growth stimulant, and, as set out below, it has the strongest evidence of any medical treatment in women.
What about natural DHT blockers?
Supplements and oils such as saw palmetto, pumpkin seed oil, rosemary oil, nettle root and biotin are widely marketed as natural DHT blockers. The honest position is that good-quality trial evidence for any of them in women is very limited or absent. Most of the research is small, laboratory-based, carried out in men, or looks at oral supplements rather than the products sold for hair. Biotin in particular is not a DHT blocker and only helps hair if you are genuinely deficient, which is uncommon. These products are not a reliable substitute for a proper assessment, and "natural" does not mean risk-free, especially alongside other medicines.
Hair loss in women is worth investigating first
Female hair loss has many causes besides female pattern hair loss, and several are treatable in their own right. Low iron (measured as ferritin), thyroid problems, polycystic ovary syndrome and telogen effluvium (a temporary, often stress or illness related shedding) can all cause or worsen thinning. For that reason it is usually more useful to have the cause assessed, including simple blood tests where appropriate, than to start a DHT blocker on the assumption that DHT is the problem. The NHS, and a GP or dermatologist, are the right first port of call.
Finasteride and dutasteride in women: licensing, evidence and safety
They are not licensed for female hair loss
Neither finasteride nor dutasteride is licensed in the UK for female pattern hair loss. Any use in women is therefore off-label, meaning a specialist is prescribing a medicine outside the conditions it was approved for, after weighing up the alternatives. Finasteride's UK licence covers male pattern hair loss (at 1mg) and benign prostate enlargement (at 5mg); dutasteride is licensed for the prostate.
The evidence in women is weaker than in men
It is only honest to say that the evidence in women does not match the evidence in men. The best-known trial, a 12-month randomised controlled study of finasteride 1mg a day in 137 postmenopausal women, found no benefit over placebo: hair counts, and patient, investigator and photographic assessments, all showed no improvement. Later studies using higher doses, of 2.5mg to 5mg a day, and studies in younger women with signs of raised androgens, have reported more encouraging results, but these were smaller, uncontrolled and lower quality, and no randomised trials of the higher doses in women have yet been carried out. The upshot is that DHT blockers cannot be assumed to work for women the way they do for men, and any possible benefit is usually discussed in premenopausal or higher-androgen women rather than after the menopause. None of the doses mentioned here is a recommendation; they are simply what particular studies used.
Pregnancy: the most important safety point
This is the single most important issue with 5-alpha-reductase inhibitors in women. Because DHT is needed for the normal development of a male baby, finasteride and dutasteride can interfere with that development, in particular the external genitalia, if taken during pregnancy. For this reason they must not be taken by anyone who is pregnant or who might become pregnant. In UK practice finasteride is treated as contraindicated in pregnancy, and it should also be avoided while breastfeeding.
Two further precautions follow from this. Crushed or broken finasteride tablets should not be handled by anyone who is pregnant or could become pregnant, because a small amount can be absorbed through the skin; intact tablets are coated to prevent this. And you should not donate blood while taking finasteride, so that it cannot reach a pregnant recipient through a transfusion. These are standard precautions set out in the product information.
Mood and sexual side effects
In 2024 the UK medicines regulator, the MHRA, introduced patient alert cards for finasteride, and in May 2026 it strengthened the warnings further. Finasteride is associated with depression, suicidal thoughts and sexual dysfunction, and these effects may persist after the medicine is stopped. Much of the reported data comes from men taking finasteride 1mg for hair loss, and a similar warning has been added for dutasteride as a precaution because it works in the same way. Anyone taking finasteride who develops low mood or suicidal thoughts is advised to stop and seek medical advice promptly. You can read the current position in the MHRA's drug safety update. Other reported effects include breast tenderness or enlargement, which is uncommon.
Better-evidenced options for women
Minoxidil
Minoxidil, applied to the scalp, is the treatment with the strongest evidence in women and is generally the first choice. It is a hair growth stimulant rather than a DHT blocker. In the UK only the 2% strength is licensed for women, while the 5% strength is sometimes used on a clinician's advice; neither is available on the NHS. It needs to be used for at least six months before any benefit shows, any benefit lasts only while it is used, and it should be avoided if you are planning pregnancy or breastfeeding. Low-dose minoxidil taken as a tablet is also used off-label in some situations and is a matter for a specialist.
Spironolactone and other anti-androgens
Spironolactone is the anti-androgen most often used for female pattern hair loss in the UK, particularly where there are signs of raised androgens, though it is used off-label and the evidence base is limited. Cyproterone acetate, flutamide and bicalutamide are other anti-androgens that are sometimes used. Like the DHT blockers, spironolactone and cyproterone acetate can affect the development of a male baby and must be avoided in pregnancy and breastfeeding. Which, if any, of these is appropriate is a decision for your doctor based on your own circumstances.
Where surgery and other options fit
No medicine can bring back follicles that have already been lost. In areas of established thinning, a hair transplant may be an option for some women, and it is worth an assessment to understand whether it is suitable. Platelet-rich plasma (PRP) and low-level laser therapy are also offered, but the research behind them is limited. Your clinic can advise on whether any of these routes fits your situation.
Frequently asked questions
Frequently asked questions
Is spironolactone a DHT blocker?
No. Spironolactone is an anti-androgen: it works mainly by blocking the androgen receptor, not by lowering DHT. It is the anti-androgen most commonly used for female pattern hair loss in the UK, but it is a different type of medicine from the DHT blockers finasteride and dutasteride. It is used off-label, and it must be avoided in pregnancy and breastfeeding.
Can I take finasteride if I might become pregnant?
No. Finasteride is contraindicated in pregnancy because it can interfere with the development of a male baby, in particular the external genitalia. It should not be taken by anyone who is pregnant or who could become pregnant, and it should be avoided while breastfeeding. Anyone who could become pregnant should also avoid handling crushed or broken tablets, and should not donate blood while taking it. If pregnancy is a possibility, this needs a frank conversation with your doctor before starting.
Do finasteride and dutasteride actually work for women?
The evidence is much weaker than in men and is genuinely mixed. The best-known trial, in postmenopausal women, found finasteride 1mg no better than placebo. Some smaller, lower-quality studies using higher doses, or in women with raised androgens, have been more positive, but there are no good randomised trials of those higher doses in women. Because they are also unlicensed for this use and carry pregnancy risks, they are not a first choice, and whether they have any place is a specialist decision.
Do saw palmetto or other natural DHT blockers work for women?
There is little good-quality evidence that they do. Most studies are small, laboratory-based, carried out in men, or look at oral supplements rather than the products marketed for hair, and biotin is not a DHT blocker at all. They should not be relied on in place of a proper assessment, and it is worth telling your doctor about any supplements you take, as "natural" does not mean risk-free.
Why did my doctor suggest minoxidil instead of a DHT blocker?
Because in women minoxidil has the strongest evidence of any medical treatment and is usually the first choice, whereas DHT blockers are not licensed for female hair loss, have weaker evidence in women, and carry risks in pregnancy. Minoxidil is applied topically to the scalp, works differently from a DHT blocker, and can be started more straightforwardly, though it too needs several months before any effect is seen.
Is it safe to handle my partner's finasteride tablets?
Handling whole, intact tablets is not considered a risk, as they are coated. The precaution applies to crushed or broken tablets, which anyone who is pregnant or could become pregnant should not handle, because a small amount of the drug can pass through the skin. If in doubt, ask a pharmacist.
The bottom line
For women, "DHT blockers" are not the clear answer they can be for men. Female pattern hair loss is only loosely linked to DHT, finasteride and dutasteride are not licensed for it and carry real risks in pregnancy, and the trial evidence in women is weak, with the best-known study showing no benefit. Spironolactone, the anti-androgen most used in women, is not a DHT blocker at all, and neither is minoxidil, which has the strongest evidence. The most useful first step is to have the cause of your hair loss assessed properly, because there is often something treatable behind it. Any decision about a DHT blocker or an anti-androgen should be made with a doctor or dermatologist who can weigh the evidence and the risks for you.
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