Finasteride

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Finasteride and Propecia specs

Finasteride and Propecia specs

Finasteride is a treatment for male hair loss. It’s the generic version of the branded Propecia. Finasteride is a 5-Alpha-Reductase inhibitor, which means it stops too much testosterone from being changed into dihydrotestosterone (DHT). DHT shrinks your hair follicles and makes your hair grow more slowly. This can lead to hair loss.

Finasteride was first used in 1992 to treat benign prostate hyperplasia (BPH), or an enlarged prostate, at a dose of 5mg. Since 1998, 1mg of Finasteride or Propecia has also been used to treat male pattern hair loss. It’s the oldest 5-Alpha-Reductase inhibitor developed to treat people, and it’s still being used. That’s because we know it really works.

Since it’s been around for a while, we know quite a lot about the efficacy of the drug. Many men are able to use the drug for several years, and find it effective at helping them maintain their hair.

Here, we’ll explain the rates of effectiveness, as well as other details like possible side effects and how to use it.

Alexandra Cristina Cowell
Medically reviewed by
Alexandra Cristina Cowell, Writer & Clinical Content Reviewer
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Reviewed on Jul 1, 2025. by Dr Alexandra Cristina Cowell Writer & Clinical Content Reviewer Next review due on Jul 1, 2028.
Alexandra Cristina

Last updated on Sep 09, 2025.

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Propecia and Finasteride - what’s the difference?

Propecia is a branded product and Finasteride is the generic version. If you’re wondering what that means, there isn’t too much of a difference. They both contain 1mg of the active ingredient finasteride, which is the part that matters when it comes to your hair.

Propecia has a recognisable name and packaging that comes with their licence to sell their brand of finasteride. Generic forms of Finasteride might sometimes look a little different, or be produced in different places. The finasteride ingredient is the most important thing, so whether it’s used in a branded product or in a generic, it works in the same way and will be just as effective.

So, if you’re not sure how to pick between Propecia and generic Finasteride, it’s really up to you. Some people prefer branded versions because they are always the same size, shape and colour. Other people like to use the generic versions of treatments like finasteride, as they usually cost less.

How does it work?

Male pattern hair loss is also called androgenetic alopecia. It’s related to male sex hormones, namely dihydrotestosterone (DHT). The function of DHT can be linked to helping you build muscle and maintain a healthy sex life. But DHT also affects the growth and health of hair follicles, and too much of it can make you start to lose the hair on your head as you age.

Finasteride’s mechanism of action is to partly block an enzyme called 5-A-R. This enzyme helps your body convert free or excess testosterone into DHT. This conversion of testosterone into DHT is a natural process, but not what you want if you’re losing hair.

Hair loss caused by DHT will begin affecting most men by the time they’re into their thirties. It affects up to 50% of men by the age of 50. Finasteride lowers your levels of DHT by stopping the conversion. This helps hair growth and stops you from losing more hair.

What else does Finasteride do?

Finasteride also comes in a 5mg dose, which is used to treat benign prostatic hyperplasia (BPH). BPH is an enlarged prostate, due to hormone changes as you get older. It isn’t cancerous, but it can cause uncomfortable symptoms such as difficulty urinating.

Finasteride reduces the size of the prostate in people with BPH. If you want to learn more about treating BPH with Finasteride, we have a page on it.

How to take Finasteride

Propecia or Finasteride for hair loss should be taken once a day. Taking it more than once won’t make it work better, and it’s not good for you. Swallow the tablet whole, make sure you don’t crush or chew it.

There’s no best time to take Finasteride, and you can take it with or without food. Try to take it around the same time every day though. Setting an alarm can help you remember when it’s time to take it.

How effective is Finasteride?

Finasteride and Propecia are effective at fighting male hair loss. Two year-long trials found that taking 1mg of Finasteride per day both reduced hair loss and increased hair growth significantly. Finasteride works longer-term too, with a 10 year study finding that 86% of men taking it had increased or stable hair growth over the years.

They measured this by both examining the hair and through asking the participants. Most of the men taking part were positive about the effects of Finasteride on their hair. So not only is Finasteride effective at improving the fullness of your hair, you’ll be sure to notice the difference.

Will it work on my temples or hairline?

Finasteride works best on the top of your head, and that’s where you’ll see the most growth. Finasteride should still work on your hairline and temples though. You’ll just need some hair there already for it to work with.

Although even if you don’t, it’s important to remember that Finasteride doesn’t just help you grow more hair. It also stops your hair from thinning. Finasteride could be a good choice to stop your temples or hairline from receding more, while giving you a thicker head of hair.

How long does Finasteride take to work?

Hair growth is a slow process for everyone, even without male hair loss. Every hair on your head goes through its own life cycle, where it grows slowly for a few years and then rests for a few months. Healthy hair will usually only grow one centimetre a month. Then, it falls out and starts growing again. Hair loss caused by DHT disrupts this process. It makes the growing phase even shorter and the hair itself often grows patchy and weak.

Finasteride will start working on your scalp very quickly, immediately working on the DHT levels affecting the follicles on your scalp. But due to the slow process of growing, it can still take a while to realise it’s working.

It often takes three months to start seeing results from Finasteride or Propecia. The full benefits can take a year to show.

How long does Finasteride stay in your system?

If you stop taking Finasteride, it should completely leave your system within a week. This is because it has a short half-life of only five or six hours. The half-life of a medication is the time it takes for a drug's active ingredient to reduce by half in the body.

After you’ve stopped taking Finasteride, your hair loss will begin again. You’ll probably lose any hair you have gained in nine to twelve months. Without Finasteride, your DHT levels will return to how they were without taking it.

Do Propecia or Finasteride pills expire?

Like most medicines, Propecia and Finasteride tablets both expire after a certain time. Make sure you check the expiry date on the packaging before you use Finasteride. Don’t take tablets after the expiry date has passed, because they will not be as safe or effective.

Can you get Finasteride on prescription?

Finasteride and Propecia are both available on prescription only. This means you’ll need to talk to a trained clinician before you take it and get their approval. It’s not the right treatment for everyone, so they’ll have to check it’s safe and right for you to use.

Prescription medications can only be dispensed by licensed pharmacies. If you’re buying Finasteride online, make sure that registered professionals are prescribing it to you. You should also check that the site is registered with the GPhC (General Pharmaceutical Council). You can make sure of this by looking out for this symbol with a unique white number on it.

You can also get a Finasteride prescription by booking an appointment with a GP. However, you can’t get Propecia or generic finasteride on the NHS, so you’ll need to get a private prescription. This is often expensive, as you will generally have to pay for a pharmacist’s charge and the cost of the medicine.

Common side effects

medically-reviewedDHT is a bit like a more potent testosterone. This means limiting DHT can be great for hair growth, but it can sometimes affect your sex life. One potential side effect can cause some people to find it harder to get an erection or find they have a lower sex drive while taking Finasteride.

Although this is rare, in some cases Finasteride has been associated with low mood or depression. If you’re experiencing new or worsening symptoms of low mood, you should stop taking Finasteride immediately and talk to your doctor.

Most people won’t experience any side effects, but be sure to seek medical advice if you have any worrying symptoms. We have a page with all the information you need to know on side effects.

What about post-finasteride syndrome (PFS)?

Post-finasteride syndrome, or PFS, refers to a range of persistent sexual, neurological, and physical side effects that a small number of men report experiencing after they’ve stopped taking the medication.

Currently, PFS is not a universally recognised medical diagnosis, and its causes and commonality are both subject to ongoing debate within the medical community. While the vast majority of men who take finasteride don’t get these side effects, or find that their side effects resolve after stopping the drug, it’s good to be aware of these reported concerns before starting treatment so you know what to look out for. If you experience any persistent or worrying symptoms while taking or after stopping finasteride, speak with your doctor right away.

Could Finasteride or Propecia be right for me?

If you’re wondering whether Finasteride or Propecia could help your with your hair loss, speak to a clinician. Although finasteride is a proven hair-loss treatment, it’s not always effective or suitable for everyone. By assessing the extent of your hair loss, as well as your health needs and history, a registered clinician will be able to help you understand whether the treatment could be safe, suitable and effective for you.

And remember, finasteride isn’t a miracle cure for hair re-growth. Many men who take it find that it mostly just works to prevent any further hair loss — so if you’re looking for something to completely reverse extensive hair loss, finasteride probably isn’t the right choice for you. You’ll need to manage your expectations or seek out alternative options.

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This page was medically reviewed by Dr Alexandra Cristina Cowell, Writer & Clinical Content Reviewer on Jul 01, 2025. Next review due on Jul 01, 2028.

Last updated on Sep 09, 2025.

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