Finasteride
Is It Right for You?
A complete guide to Finasteride — what it treats, how it works, dosages, side effects, and when a clinician may prescribe it following an online consultation.
What Is Finasteride?
Finasteride is a medicine used to treat male pattern hair loss and an enlarged prostate (benign prostatic hyperplasia). It works by lowering levels of a hormone that contributes to both conditions.
It is taken as a tablet, with a 1 mg dose used for hair loss (brand name Propecia) and a 5 mg dose used for an enlarged prostate (brand name Proscar). It is available generically at both strengths.
Finasteride is a prescription-only medication in the UK. A licensed clinician can review your suitability and medical history through a telehealth consultation and prescribe it where appropriate.
What Conditions Is Finasteride Used For?
Finasteride is used for:
slowing hair loss and promoting some regrowth at the crown and mid-scalp in men.
shrinking an enlarged prostate to ease urinary symptoms.
improving flow and reducing the risk of complications from prostate enlargement.
Finasteride can harm the development of a male baby. Pregnant women, or those who may become pregnant, must not take it or handle crushed or broken tablets. Intact tablets are coated to prevent contact with the active ingredient.
How Does Finasteride Work?
Finasteride blocks an enzyme called 5-alpha-reductase, which converts testosterone into a stronger hormone called dihydrotestosterone (DHT).
DHT shrinks hair follicles in male pattern baldness and contributes to prostate growth. By lowering DHT levels, finasteride slows hair loss and helps shrink an enlarged prostate.
Because it works on the hair cycle and prostate gradually, benefits build over months, and the effect on hair is maintained only while treatment continues - stopping usually reverses the gains over time.
Dosages & Administration
The correct dose depends on the type and severity of infection, age, weight, and kidney function. Always follow your clinician's instructions. The table below is for general reference only.
Administration Tips
Take one tablet a day at a similar time, with or without food, and swallow it whole without crushing or breaking it.
Be patient and consistent; it can take several months to see an effect on hair, and benefits are maintained only while you keep taking it.
Side Effects of Finasteride
Most people tolerate finasteride well. The most discussed side effects relate to sexual function and mood.
- Reduced sex drive
- Difficulty getting or keeping an erection
- Problems with ejaculation
- Breast tenderness or enlargement
- Skin rash
- Low mood
- Persistent sexual side effects that continue after stopping (reported by some)
- Significant low mood, depression, or suicidal thoughts
- Breast lumps, pain, or nipple discharge (rare; possible breast cancer sign)
- Severe allergic reaction (swelling of lips, face, throat)
Seek advice if you experience significant low mood or depressive thoughts. Also report any breast lumps, pain, swelling, or nipple discharge promptly, as breast changes need to be checked.
Drug Interactions
Always disclose all prescription drugs, over-the-counter medicines, vitamins, and supplements to your clinician or pharmacist before starting finasteride.
Finasteride has relatively few important interactions, but always tell your clinician about all your medicines and supplements.
Finasteride lowers PSA levels, which is used in prostate screening; tell any clinician interpreting a PSA test that you take it.
Tell your clinician if you use testosterone or other hormones, as they act on the same system.
Important Warnings
Finasteride can harm a developing male baby. Women who are or may become pregnant must not take it or handle crushed or broken tablets.
For hair loss, benefits are maintained only while you keep taking finasteride. If you stop, hair loss usually resumes over the following months.
Finasteride lowers PSA, which can affect prostate cancer screening. Any prostate symptoms should still be assessed, and your PSA results interpreted with this in mind.
Some men experience sexual side effects or mood changes. Discuss any concerns with your clinician, as these may affect whether you continue.
Speak to a Clinician About Treatment
Getting advice no longer means sitting in a waiting room. Through The GP Service, you can consult with a licensed clinician in minutes — from home, on your lunch break, or wherever works for you. If treatment is clinically appropriate, your clinician can issue a prescription during the consultation. A consultation does not guarantee a prescription.
The treatment you need, when you need it.
Finasteride FAQs
Yes. A licensed clinician can review your suitability and medical history through a telehealth consultation and prescribe finasteride for hair loss or prostate symptoms where appropriate.
It usually takes three to six months of daily use to see an effect, and the benefit continues only while you keep taking it. Stopping reverses the gains over time.
Finasteride is licensed for male pattern hair loss and is not generally used for women, particularly those who could become pregnant, due to the risk to a developing baby.
Most sexual side effects resolve on stopping, but some men report persistent effects. Discuss any concerns with your clinician before and during treatment.
Yes. Finasteride lowers PSA levels, so tell any clinician interpreting a PSA test that you take it, so the result can be adjusted appropriately.
Finasteride and topical minoxidil work in different ways and are sometimes used together for hair loss. A clinician can advise whether combining them suits you.