Finasteride Tablets: Risks, Side Effects & Dosage

  1. What is Finasteride prescribed for?
  2. How does it work?
  3. What are the side effects?
  4. What are the risks of taking Finasteride?
  5. Can it interfere with other medication?
  6. Typical dosages
  7. Taking Finasteride safely
  8. Key factors to consider
  9. Alternatives

Finasteride is a common treatment for hair loss, primarily male pattern baldness. It’s available in tablet form only, to be taken by mouth, and as generic and brand-name products (such as Propecia and Proscar).

Finasteride is also used to treat prostate enlargement, known as benign prostatic hyperplasia. 

If you’re considering trying finasteride for hair loss, research is crucial to ensure you understand how it works and its potential side effects.

We’ve created this reader-friendly guide to give you the answers you need before you take finasteride for the first time.

We’ll cover everything from how finasteride affects the body to alternative hair loss treatments.

Why do people take Finasteride? 

Finasteride is an oral tablet available by prescription only, rather than an over-the-counter (OTC) drug.

You can buy branded finasteride tablets like Propecia or Proscar, or you can try generic versions as a lower-cost alternative.

However, generic finasteride tablets may not come in the same forms or strengths as branded products. 

Doctors typically prescribe Propecia and Proscar to treat specific conditions: 

  • Propecia for male pattern baldness, which affects around 50% of men over the age of 50 in the UK. 
  • Proscar for symptoms of enlarged prostate, possibly prescribed with other drugs. For example, doxazosin can reduce the danger of symptoms progressing. 

Doctors won’t prescribe finasteride tablets for women or children.

How does Finasteride work? 

Finasteride decreases the amount of DHT in the body.

As a sex hormone, DHT plays a critical role in the development of “male” characteristics, such as more body hair and a deep voice.

However, DHT can also increase the size of your prostate and shrink hair follicles on the scalp over time, ultimately leading to hair thinning or baldness. 

By decreasing the amount of DHT in your body, finasteride may help stop your prostate from getting bigger, reduce hair loss, and stimulate hair growth on the scalp (without affecting hair growth in other areas of the body).

Finasteride for Hair Loss

What are the side effects of taking Finasteride? 

Finasteride can trigger a number of side effects, some of which may be serious.

The most common, though, can pass without needing treatment.

Common effects 

Patients taking finasteride may experience these fairly common side effects: 

  • Skin rash
  • Sex drive decrease
  • Difficulty getting and maintaining an erection
  • Ejaculation disorder
  • Breast growth and tenderness 

Each of these effects could fade within a couple of weeks, but speak to your doctor or a pharmacist if they persist or become serious.

Riskier side effects 

Contact your doctor immediately if you develop any of the below effects, or dial 999 if you believe you’re experiencing a life-threatening emergency.

Potentially serious side effects of finasteride include: 

  • Depression
  • Swollen tongue, throat, face, or lips
  • Nipple discharge
  • Breast pain or lumps

Please note: Drugs can affect everyone in a different way. As a result, it’s not possible to guarantee that we’ve covered all potential side effects in this guide. Always consult a doctor who knows your medical history if you’re concerned about how finasteride may affect you or you want further advice on possible side effects.

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What are the risks of taking Finasteride? 

Please read the following warnings before you take finasteride to treat hair loss:

Fetus defect risk 

If you’re pregnant or intend to become pregnant, avoid handling finasteride tablets that have been broken or crushed.

Physical contact with the drug, even if it simply touches your skin, may cause defects in developing male fetuses.

Prostate cancer risk 

Taking finasteride could lead to an irregular type of prostate cancer or a form that grows faster, due to it’s ability to reduce prostate specific antigen (PSA) levels.

An increased PSA level has been connected to prostate cancer. You should speak to your doctor if your PSA levels rise after you take finasteride.

Allergic reactions 

Finasteride may trigger severe allergic reactions in some people. Possible symptoms include: 

  • Swollen tongue or throat
  • Hives
  • Breathing difficulties 

Call 999 or seek assistance from a healthcare provider immediately if you develop any of these symptoms. Also, avoid taking it again if you experience an allergic reaction to the drug, as further symptoms may be more severe — possibly fatal.

Skin contact 

Women who are currently pregnant or intend to be should avoid making physical contact with finasteride, as it can penetrate the skin and possibly lead to birth defects.

Existing health conditions 

Finasteride can be dangerous for people with: 

Liver disease 

Finasteride is processed in the liver, and your body could take longer to process it if you have liver disease. As a result, it may build up and increase your risk of experiencing side effects.

Your doctor could prescribe a reduced dosage to compensate for this risk. 

Prostate cancer 

Finasteride may make prostate cancer worse, as it increases the risk of developing an irregular form of the disease and could make it grow faster than it might otherwise.

Who else should avoid finasteride? 

  • Pregnant women: Doctors do not prescribe finasteride for women, especially during pregnancy. 
  • Breastfeeding women: Women breastfeeding their children should never take finasteride, as it’s unknown whether or not this drug can be passed on via breast milk. 
  • Children: Researchers have not yet identified if finasteride is safe or effective for children, so doctors won’t prescribe it for a child. 

Always check with your doctor if you’re unsure whether or not finasteride is suitable for you.

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Can Finasteride interfere with other medications? 

Finasteride could interact with other drugs you take, which may be dangerous or stop the drug from doing what it should. That’s why your doctor should take care when prescribing it, and discuss any other medications you take first. 

Inform your doctor if you’re taking medications, products for hair growth, herbs, or hair growth vitamins. Always ask your doctor or pharmacist about how finasteride tablets could interact with your other medications or tablets to ensure you understand the potential risks.

How should you take Finasteride? 

We’ll provide a summary of recommended dosages below, but this list does not represent all potential dosages available.

Your dosage, and the frequency with which you should take finasteride, will be based on: 

  • The condition to be treated (e.g. male pattern baldness)
  • Your age
  • The severity of your condition
  • Your reaction to your initial dose of finasteride
  • Additional medical conditions you have

Treatment for male pattern baldness 

  • Generic treatment: Finasteride, 1 mg oral tablet 
  • Branded treatment: Propecia, 1 mg oral tablet 

Dosage for Adults (18+): 1 mg daily. 

Dosage for children (younger than 18 years old): There is no established dosage for people below 18 years of age, and finasteride is never prescribed for children.

Treatment for benign prostatic hyperplasia 

  • Generic treatment: Finasteride, 5 mg oral tablet
  • Branded treatment: Proscar, 5 mg oral tablet 

Dosage for Adults (18+): 5 mg daily. 

Dosage for children (younger than 18 years old): There is no established dosage for people below 18 years of age, and finasteride is never prescribed for children. 

Speak to your doctor before you start taking finasteride to confirm the right dosage to treat your male pattern baldness.

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Taking Finasteride safely 

Doctors prescribe finasteride as a long-term method of treating male pattern baldness or prostate enlargement. It’s critical that you take your tablets as prescribed to avoid potential risks. 

Here are frequently asked questions about taking finasteride:

What if you don’t take all of your finasteride? 

You may not experience renewed hair growth if you don’t take all of the finasteride tablets prescribed to you as directed. If you take it to combat male pattern baldness, your hair may not regrow as hoped for or at all. Also, prostate issues are unlikely to resolve as required.

What if you take too much finasteride? 

You’ll be at higher risk of experiencing negative effects if you take more of your finasteride than you should. For example, you may struggle to get an erection and stay aroused, develop ejaculation disorder, get a skin rash, or see your breasts increase in size or become more tender.

What if you miss a dosage of finasteride? 

If you forget to take your finasteride on one or more days, never take extra tablets to compensate. Take the next one as you should and continue from there.

How do you know if your finasteride is having the desired effect? 

If you take finasteride for hair loss, you’ll see that the drug is failing to stimulate hair growth: your scalp will remain bald in the usual areas, and further shedding may occur. And if your doctor prescribes finasteride to treat an enlarged prostate, you could feel less need to urinate, see an improved flow of urine, and feel as if your bladder never empties fully.

Key factors to consider before you take Finasteride 

If your doctor prescribes finasteride to treat your hair loss, keep the following factors in mind:

General safety 

Never cut, chew, or crush your tablets. Only take as directed.


Keep finasteride stored at room temperature, from 15°C to 30°C. Store it outside of high temperatures and away from light sources. Also, never keep your finasteride in your bathroom or any other room prone to moisture.

Refilling Finasteride prescriptions 

You should be able to refill your finasteride prescription without the need for a new prescription. Your doctor will authorise a specific number of refills when writing your prescription.

Travelling with Finasteride 

You should keep your finasteride on your person when travelling, and store it in your carry-on luggage while flying. Passing your bag through an x-ray machine at an airport won’t damage your finasteride, but you may be asked to present your pharmacy label. Always carry the original container with the prescription label on you just in case. 

When driving, never leave your finasteride in the glove box or anywhere else in your vehicle — especially in extremely hot or cold conditions.

Monitoring the effects of Finasteride 

Monitoring is necessary to track how finasteride affects your PSA levels. 

Speak to your doctor about these factors, and any other concerns you may have, before you start taking finasteride. It’s likely that they’ll discuss alternative hair restoration treatments with you too.

What other hair loss treatments are available? 

If you have male pattern baldness or another hair loss condition, a hair transplant may be the ideal treatment.

The latest hair restoration procedure, FUE2, is designed to restore hair on one or more parts of the scalp with success rates of up to 90 – 95%. 

A surgeon will transplant healthy hair follicles to thinning or bald areas to stimulate new growth with natural results.