DHT Blockers

How Do DHT Blockers Work for Hair Loss?

Male pattern baldness is a common problem that’s experienced by many men in the UK. Because the condition is caused by sensitivity to a hormone called DHT (dihydrotestosterone), medicines that block the effects of this hormone are thought to stop or even reverse the effects of male pattern baldness.

Dr Simran Deo Medical Editor

Medically reviewed by

Dr Simran Deo

Last reviewed: 26 Mar 2020

What is a DHT Blocker?

DHT prevents nutrients from being absorbed by hair follicles, which causes them to shrink and eventually cease to grow hair. There are several natural remedies available online that claim to have a DHT blocking effect, these include:

  • Green tea
  • Nettle
  • Saw palmetto
  • Pumpkin seeds

Although using a natural remedy for male pattern baldness appeals to many men, unfortunately there is no scientific evidence to support the claim that they work.

There are currently just two medicines available that are considered to be effective in treating male-pattern baldness; finasteride and minoxidil. Neither are available on the NHS, although they can be obtained on a private prescription (finasteride) or from a pharmacy over the counter (minoxidil).

How do They Work for Hair Loss?

Because DHT makes hair follicles shrink, using a DHT blocker stops this from happening, which lets the hair follicles grow back to their normal size.

Which DHT Blockers Are There?

There are two main licensed treatments for hair loss caused by male pattern baldness, Finasteride (Propecia) and Minoxidil (Regaine).


Finasteride (Propecia) is a tablet that you take every day. It’s thought to work by stopping testosterone, being converted into dihydrotestosterone (DHT).

There have been studies that have indicated that using finasteride increases the number of hairs as well as improving the appearance of your existing hair.

Propecia isn’t a quick fix - it can take from three to six months before you’ll see any effect from using it and it has to be taken every day. You’ll need to use it long term too, because if you stop using it, the balding process tends to start again within six months to a year.

Minoxidil (Regaine)

Regaine is the name of a minoxidil based lotion that you rub into your scalp every day. It’s available without prescription from pharmacies. Although it’s not clear exactly how it works, it does seem to help hair regrowth in some men.

Regaine is available as a lotion or foam, and in two different strength products. Minoxidil based hair loss products usually contain either 5% or 2% minoxidil.

Regaine is another long term treatment option, and you’ll need to use it every day for several months before you notice any effects on your hair regrowth. Like Propecia tablets, if you stop using the lotion, your balding will start again after a while. Not only that, but any new hairs that have grown since treatment was started are likely to fall out within a couple of months of you stopping using the lotion.

How Effective Are DHT Blockers?

Propecia can lower DHT levels in the scalp by as much as 60 per cent if you take it every day. This stopped the progression of hair loss i n 86 per cent of men who took it during clinical trials. 65 per cent of people who took part in the trial reported a substantial increase in their hair growth.

Although minoxidil (Regaine) has been clinically proven to slow down the progression of hair loss and start hair regrowth, it doesn’t affect the hormonal process of hair loss, and so some experts see it as a temporary solution. There is some evidence that the higher percentage products can be more effective than the lower dose versions, although some studies also showed that there wasn’t any difference between the two as far as effectiveness is concerned.

How Do I Use DHT Blockers?

Propecia is a tablet which you’ll need to swallow whole, with or without food, once a day.

Try to remember to take it at the same time every day.

Regaine solution and foam are usually applied directly to the scalp, twice a day. You mustn’t use it more than twice a day, and always follow the instructions on the pack and/or patient information leaflet. You should also try to use it at the same time each day.

Do DHT Blockers Cause Any Side Effects?

Propecia side effects aren’t common, although like all medicines, they can happen.

Less than one in 100 men who take Propecia might experience a loss of sex drive (libido) or erectile dysfunction. Other reported side effects include:

  • ejaculation problems (such as a lower volume of semen released during sex)
  • enlarged or tender breast areas
  • Increased hepatic enzymes
  • Rash, pruritus
  • pain in the testicles

Regaine may also cause side effects - these are more likely in products containing 5% minoxidil. Side effects aren’t usually serious but if they persist, or you think they are severe, see your doctor.

The most common symptoms are dryness or itchiness where the product is applied, redness and/or a flaky scalp.

Other side effects include:

  • changes in the texture of newly grown hair
  • Increased growth of facial hair
  • increased hair loss
  • itchy eyes
  • Headaches
  • skin reactions - acne and dermatitis

Who Shouldn’t Use DHT Blockers?

If you’re due to have a blood test for prostate-specific antigen (PSA), ask your doctor for advice as you may need to avoid using Propecia. Women, children or adolescents shouldn’t use it.

If you have a heart condition, including angina, ask your doctor’s advice before using Regaine. If any of the below also apply, you shouldn’t use it.

  • If you’re allergic to minoxidil or any other ingredient in Regaine
  • If you have high blood pressure or you’re taking high blood pressure medication
  • If you have psoriasis or any other scalp condition
  • If you have a shaved scalp or are using dressings on your scalp
  • If you’re under the age of 18, or over the age of 65

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