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Finasteride (propecia) side effects

Finasteride (propecia) side effects
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What is finasteride?

Finasteride is a ‘5-alpha reductase inhibitor’. Finasteride is a hair loss tablet that contains the same active ingredient as the branded version, propecia.

How does finasteride work? 

Finasteride blocks the effect of dihydrotestosterone which is a type of testosterone that shrinks the hair follicles. This means the follicles can continue to allow hair growth, which reduces shedding of hair.

One tablet must be taken every day for as long as you wish to combat hair loss, improvement is usually seen at 3-6 months. It is only available on prescription and is licensed by the UK medical regulatory body, the MHRA. A small number of men may experience side effects, read on to find out more. 

Side effects of finasteride

Uncommon side effects (affects between 1 in 1000 and 1 in 100 people)

  • Depression (if you experience this you should stop finasteride immediately and seek advice from your GP)
  • Decreased libido
  • Erectile dysfunction
  • Ejaculation disorder (this includes decreased volume of ejaculate)

Sexual dysfunction includes erectile dysfunction, reduced libido and reduced volume of ejaculate. In most people these side effects resolve with continued treatment or after stopping finasteride. However, there is a small chance that sexual dysfunction can remain a permanent effect even after stopping finasteride.

Frequency unknown but very rare

  • Hypersensitivity reactions (rash, itchiness, urticaria and swelling of lips, tongue, throat and face)
  • Suicidal thoughts (if you experience this please stop finasteride immediately and seek advice from your GP)
  • Breast tenderness and enlargement (this may contribute to male breast cancer, so if you notice any breast changes please seek advice immediately from your GP)
  • Infertility (if you are planning to father a child you may want to consider stopping treatment)
  • Palpitations
  • Increased liver enzymes
  • Testicular pain

As finasteride shares the same active ingredient as propecia, men can feel confident in using this option once their suitability has been checked. The side effects are the same, and the likelihood of developing them is no greater than with propecia.

Are finasteride and propecia the same thing?

Yes, Propecia is the branded version of Finasteride and they both work in the same way.

Hair loss treatments

How much is finasteride and propecia?


Propecia is not currently available on the NHS, but it can be prescribed privately. You can request propecia online through the LloydsPharmacy Online Doctor service where a clinician will make sure it's suitable for you. Prices start at £55. 

Finasteride (Generic Propecia)

Finasteride is the non-branded form of Propecia. It also may be privately prescribed by our Online Doctor hair loss clinic with an online consultation that ensures your suitability. Prices start at £28. 


Image for illustrative purposes only. Posed by models.