Dutasteride

Dutasteride is a capsule taken by mouth that belongs to a group of medications called 5-alpha reductase (5-AR) inhibitors. It’s licensed to treat benign prostatic hyperplasia (BPH), but can also be used off-label to treat male pattern hair loss, also commonly known as male pattern baldness.

Dutasteride is a generic medication containing the active ingredient dutasteride. It can also be found under the brand name Avodart.

Dutasteride treats male pattern hair loss by reducing the hormone dihydrotestosterone (DHT).

DHT causes male pattern hair loss by shrinking hair follicles gradually (over 5 to 15 years), in a process called miniaturisation. As your hair follicles shrink, hair starts to become thinner, before the hair follicle closes completely, causing baldness.

DHT is converted in your body from testosterone by enzymes called 5-alpha reductase. Dutasteride blocks these enzymes from working properly, lowering DHT levels. This helps to:

• stop the follicles from shrinking further, preventing any more hair loss
• encourage regrowth of thicker, healthier hair

How long does dutasteride take to work?

Dutasteride will start working straight away, but it can take some time for your hair to start regrowing. You should start noticing improvements in around 3 months, with the best results seen after 6 months of daily use.

How long does dutasteride last?

Dutasteride has a long half-life (how long it takes for half of the medication to leave your system) of around 3 to 5 weeks when taken as a daily treatment. This means it can remain in the body for up to 4 to 6 months after stopping treatment, though its effects will reduce over time.

Dutasteride works for as long as you take it. If you stop taking it, your hair will go back to how it was before treatment in around 6 months.

How effective is dutasteride?

In a clinical trial of men aged 20 to 50 years old, dutasteride 0.5mg was shown to significantly improve hair growth over 24 weeks, increasing both hair count and width when compared to finasteride and a placebo.

In studies looking at the reduction of DHT, dutasteride was shown to lower DHT levels by 90% after 2 weeks of daily treatment.

The standard dose of dutasteride for hair loss is one 0.5mg capsule taken once daily at any time of day. Swallow the capsule whole with water. It can be taken with or without food, but should be taken at the same time each day. Do not take more than the recommended dose.

How long do you need to take dutasteride for?

Dutasteride for male pattern hair loss is a long-term treatment. This means as long as it remains safe for you to take, it can be used for as long as you want to treat hair loss.

It might take some time to notice results with dutasteride, so it’s important to keep taking your capsule every day. Usually, you should see results within 3 to 6 months. It can help to take some progress photos of your hair to see the difference.

If you stop taking dutasteride, hair loss will return within 6 months.

You can get dutasteride tablets for hair loss privately through online services like Asda Online Doctor. It’s not available for hair loss on the NHS as it’s an off-label use, and cannot be bought over the counter.

Can I buy dutasteride online?

Yes, you can get a prescription for dutasteride from Asda Online Doctor. To use our hair loss service and access effective, prescription treatments, simply:

1. Complete our quick and confidential online consultation, which will ask about your hair loss symptoms and medical history.
2. One of our UK-registered doctors will review your answers and, if suitable, issue a prescription for dutasteride.

We offer a convenient, 100% confidential service, with no need for a face-to-face doctor visit. Your dutasteride tablets will be discreetly delivered to your home or can be collected from your nearest Asda Pharmacy for your convenience.

Can I buy dutasteride over the counter?

No, dutasteride is not available to buy over the counter because you need a prescription.

Can I get dutasteride on the NHS for hair loss?

No, you cannot get dutasteride on the NHS for hair loss. You can get it on the NHS to treat an enlarged prostate, but hair loss is an off-label prescription which can currently only be accessed through private providers.

Like all medications, dutasteride can cause side effects. Your doctor will check your medical history before prescribing to make sure it’s safe for you to take.

Common side effects (may affect up to 1 in 10 people) include:

• difficulty getting or maintaining an erection (erectile dysfunction)*
• reduced sex drive (libido)*
• ejaculation problems, such as a reduced amount of semen during sex*
• breast enlargement or tenderness (gynecomastia)
• dizziness when taken with tamsulosin – a medication used to treat an enlarged prostate, so this is not likely if you’re taking dutasteride for hair loss

*These side effects may persist after stopping treatment. Speak to your doctor straight away if you get these symptoms.

Uncommon side effects (may affect up to 1 in 100 people) include:

• hair loss (usually from the body) or hair growth
• heart failure (the heart becomes less efficient at pumping blood around the body) – symptoms include shortness of breath, extreme tiredness, and swelling in the ankles and legs (oedema)

Other side effects have also been reported on dutasteride, but it’s not yet known how often they occur. Other side effects include:

• swelling and pain in the testicles
• depression

Rarely, dutasteride can cause a serious allergic reaction. If you get any of the following symptoms, this is a medical emergency, and someone must call 999 straight away:

• skin rash or hives (a nettle-type rash)
• swelling of the face and throat
• difficulty breathing
• collapse

For more information on side effects, please see the patient information leaflet that comes with your medication.

How long do dutasteride side effects last?

Dutasteride side effects may last a few weeks to a few months as your body adjusts to the medication, but some can last as long as you take it. Temporary hair shedding (hair loss) can happen when you first start dutasteride, but it usually gets better after a few months and is a sign the medication is working.

Certain side effects, such as changes in sex drive, and erection and ejaculation problems, have been known to continue even after you stop taking dutasteride. These changes are usually reversible but can take a few weeks to months to resolve. It’s important to discuss any concerns you have with your doctor before taking dutasteride, especially if you’re planning to have a baby.

What to do if you get dutasteride side effects?

If you get any dutasteride side effects, you must speak to your doctor and monitor them closely. If any are persistent, severe, or affecting your life, dutasteride may not be the right hair loss treatment for you. In a medical emergency, such as a serious allergic reaction or severe depression that is causing suicidal thoughts, go to A&E or call 999.

If you get erection problems while using dutasteride, you may be able to use erectile dysfunction treatment. Speak to your doctor for more information, or if you’re prescribed dutasteride through Asda Online Doctor, message one of our doctors for free through your online account for support and advice.

Are there any permanent side effects?

There’s no research to suggest that dutasteride side effects are permanent. Dutasteride can sometimes affect your fertility even after you stop taking it, such as causing ongoing erection or ejaculation problems, lowering your sex drive, or affecting your sperm quality and count. However, this is reversible in most cases, but recovery can take several months.

Dutasteride may not be suitable for everyone, as it can interact with certain medications or underlying health conditions. These interactions could reduce the effectiveness of the drug or make dutasteride unsuitable.

Do not take dutasteride if you:

• are allergic to dutasteride, other 5-alpha reductase inhibitors, or any other ingredients in the capsules
• are under 18
• are a woman
• have severe liver disease

Before taking dutasteride, speak to your doctor if you have:

• any liver problems
• an upcoming blood test for PSA (prostate-specific antigen), which can be used to test for prostate cancer – dutasteride may affect the results as it can lower PSA in your blood
• or have ever had depression – while evidence is still limited on the link between dutasteride use and depression, it belongs to the same medication group as finasteride, which has been known to cause severe depression

In a clinical study of men at high risk of prostate cancer, those taking dutasteride developed a serious form of prostate cancer more often compared to men who did not take it. While taking dutasteride, it’s recommended that you see your GP for a PSA test and prostate exam before taking it, and at regular intervals during treatment.

These checks can help detect any signs of a prostate problem early on, and how often you need them will depend on your prostate cancer risk and age.

Dutasteride and other medications

Make sure to tell your doctor or pharmacist if you're on any other medications, as some can interact with dutasteride and increase the chance of side effects. These include:

• verapamil or diltiazem, for high blood pressure
• ritonavir or indinavir, for HIV
• itraconazole or ketoconazole, for fungal infections
• nefazodone (an antidepressant)
• alpha-blockers, for enlarged prostate or high blood pressure

If you're taking any of these, let your doctor know, as your dose might need to be changed.

Dutasteride and pregnancy

Dutasteride should not be taken or handled by a person who is pregnant or breastfeeding. The active ingredient in the capsules can be absorbed through the skin and may affect the normal development of the baby. While you’re taking dutasteride, small amounts may also be present in your semen. If your partner is pregnant or breastfeeding, use condoms and avoid any semen coming into contact with them.

Dutasteride and fertility

Dutasteride can affect your fertility while taking it, and for several months after stopping. Clinical studies show it decreases sperm count, semen volume, and sperm motility (the ability for sperm to swim through the female reproductive tract).

Dutasteride is not the only hair loss treatment available. At Asda Online Doctor, if dutasteride is not suitable, or you want to try a different medication, we also prescribe finasteride.

Dutasteride vs finasteride

Finasteride 1mg is a generic, unbranded daily tablet that belongs to the same medication group as dutasteride: 5-alpha-reductase inhibitors. This means it works in the same way by reducing levels of DHT, the hormone that causes male pattern hair loss. Propecia 1mg is the branded version of finasteride, containing the same active ingredient and working in the same way.

In clinical trials comparing dutasteride vs finasteride, dutasteride 0.5mg resulted in greater increases in hair count and hair width at week 24 compared to finasteride 1mg and placebo, with similar safety profiles.

In a 2025 meta-analysis comparing 33 male pattern hair loss treatment studies, dutasteride 0.5mg was found to be the most effective option, over finasteride tablets and topical treatments.

Other hair loss treatments

You can also get over-the-counter hair loss tablets or treatments that are applied directly to the scalp, such as topical minoxidil, commonly found under the brand name Regaine for Men. Hair loss supplements may also help if you’re not getting the right nutrition in your diet for your scalp and hair health, but there is no large-scale evidence to show how effective supplements are for male pattern hair loss, and they cannot regrow your hair.

You can usually use over-the-counter hair loss treatments alongside medicated treatments like dutasteride, but speak to your doctor first.

Is there also a topical version of dutasteride?

Yes, some companies have compounded dutasteride capsules to create a topical version. This means they have taken the medication in the capsules to create a topical version of the treatment through a special process for use on the scalp. However, the use of topical dutasteride is not licensed in many countries and may not be safe if bought from an unlicensed company.

Can you take dutasteride and minoxidil together?

Yes, studies show that taking dutasteride and minoxidil together can improve the thickness of hair. You should always speak to your doctor before using any other treatments alongside dutasteride.

Is dutasteride safe?

Yes, dutasteride is safe as long as it’s been prescribed by a doctor and they know your medical history and any medications you take. It’s also important to have regular prostate checks to reduce the risk of developing serious prostate problems.

It may not be safe to take dutasteride if you’ve not been prescribed it, you get it from an unregulated source, or you take more than you’ve been prescribed.

Can you switch from finasteride to dutasteride?

Yes, if finasteride is not the right treatment for you, you may be able to switch to dutasteride instead. If you get side effects from finasteride, you may not get them from dutasteride, as every person reacts differently to each active ingredient. They do, however, belong to the same medication group, so if you cannot take finasteride due to a certain medical condition or medication, dutasteride may also not be suitable.

Can women take dutasteride?

No, women should not take dutasteride, and it’s very important that women who are pregnant, trying to get pregnant, or are breastfeeding do not come into contact with the capsules. This also includes not coming into contact with your semen if you take dutasteride, as it can be absorbed through the skin and small amounts of the medication can pass through your semen.

Can dutasteride regrow hair on a receding hairline or temples?

It depends. Dutasteride can regrow hair on a receding hairline or temples if the hair follicles are still present. It cannot regrow hair in bald places as it cannot create new hair follicles. If you’re not sure, speak to your doctor, who may be able to examine your hair and provide further information.

Other treatments are available if this is the case, such as a hair transplant or the use of a toupee.

Is there a difference between Avodart and generic dutasteride?

Not really. Avodart is just the branded version of dutasteride. The manufacturer is different, and branded medications are usually more expensive, but the active ingredient and medication are the same, and they work in the same way.