Finasteride Side Effects: What Men Should Know Before Taking It

The main side effects of finasteride tablets include reduced sex drive, erectile dysfunction, ejaculation problems, low mood, depression, breast tenderness or swelling, testicular pain and allergic reactions.

Most men taking finasteride do not get side effects. However, because some side effects can affect sexual function, mood and quality of life, it is important to understand the risks before starting treatment.

Finasteride 1mg is used to treat male pattern hair loss. It works by reducing dihydrotestosterone, known as DHT. DHT is the hormone that causes hair follicles to shrink in men with genetic hair loss. Lowering DHT can slow hair loss and support regrowth, but it can also cause side effects in some men.

Further reading: How does finasteride work?

Finasteride side effects are uncommon, and most men take finasteride without significant problems. The most commonly discussed side effects are sexual side effects, including reduced libido, erectile dysfunction and ejaculation problems.

In clinical studies, these side effects were reported in a small proportion of men. However, they are important because they can be distressing and may affect confidence, relationships and mental wellbeing.

The risk is not the same for everyone. Men with a history of sexual dysfunction, depression, anxiety or suicidal thoughts should discuss this with a prescriber before starting finasteride.

Finasteride can cause sexual side effects in some men. These may include:

• reduced sex drive
• erectile dysfunction
• ejaculation problems
• reduced semen volume
• difficulty reaching orgasm

Sexual side effects may improve after stopping finasteride. In some cases, symptoms may improve while continuing treatment. However, some men have reported sexual side effects continuing after stopping finasteride.

You should speak to a doctor or pharmacist if sexual side effects are persistent, distressing or affecting your mental wellbeing.

Yes, finasteride can cause erectile dysfunction in some men. Erectile dysfunction means difficulty getting or keeping an erection firm enough for sex.

However, erectile dysfunction can also be caused by many other factors, including stress, anxiety, depression, alcohol, smoking, obesity, diabetes, high blood pressure and other medicines.

If erection problems start after taking finasteride, it does not always mean finasteride is the only cause. However, it should still be taken seriously. Speak to a healthcare professional if symptoms continue, become distressing or affect your quality of life.

Yes, reduced libido is a recognised side effect of finasteride. This means you may feel less interested in sex than usual.

For some men, this may be mild and temporary. For others, it can be more noticeable and distressing. If your sex drive changes after starting finasteride, speak to your prescriber or pharmacist for advice.

You should not increase, reduce or stop the dose without medical advice unless you develop depression or suicidal thoughts, in which case you should stop finasteride 1mg and contact a doctor as soon as possible.

Yes, low mood, depression and suicidal thoughts have been reported in men taking finasteride.

Before starting finasteride, tell your prescriber if you have ever had depression, suicidal thoughts, anxiety or significant mental health problems. You should also tell a partner, family member or close friend that finasteride can sometimes affect mood, as they may notice changes before you do.

If you are taking finasteride 1mg for hair loss and develop depression or suicidal thoughts, stop taking finasteride and contact a doctor as soon as possible.

If you feel at risk of harming yourself, call 999 or go to A&E immediately.

Some sexual side effects have been reported to continue after stopping finasteride. These include reduced libido, erectile dysfunction and ejaculation problems.

This does not happen to most men, but it is important to be aware of before starting treatment. Many side effects improve after stopping finasteride, but persistent symptoms should be reviewed by a doctor.

If side effects continue after stopping, a doctor may assess other possible causes such as hormone levels, mental health, other medicines, lifestyle factors, cardiovascular health or underlying erectile dysfunction.

Post-finasteride syndrome is a term used to describe persistent symptoms reported by some men after stopping finasteride. These symptoms may include sexual dysfunction, low mood, anxiety, fatigue, brain fog and reduced quality of life.

The exact cause is not fully understood, and the condition remains debated. However, persistent sexual side effects and psychiatric symptoms have been reported, so patients should be informed about these risks before treatment.

If you believe you have ongoing symptoms after stopping finasteride, speak to a doctor. Do not self-diagnose or assume all symptoms are caused by finasteride, as other medical or psychological causes may need to be ruled out.

Finasteride may affect semen volume and, in some cases, fertility parameters. This is more relevant for men who are actively trying to conceive or who already have fertility problems.

If you are trying for a baby, have known fertility issues or are concerned about semen changes while taking finasteride, speak to a doctor before continuing treatment.

Finasteride should not be handled by women who are pregnant or may become pregnant if the tablets are crushed or broken, as it may affect the development of a male baby.

Finasteride can rarely cause breast tenderness, swelling, lumps or nipple discharge.

You should contact a doctor promptly if you notice:

• a lump in the breast or chest area
• breast pain or swelling
• nipple discharge
• changes in breast tissue

These symptoms are uncommon, but they should be assessed to rule out serious causes.

Finasteride can affect prostate-specific antigen, known as PSA, blood test results. PSA tests are sometimes used to help assess prostate health.

If you are having a PSA blood test, tell your doctor that you are taking finasteride. This helps them interpret the result correctly.

Finasteride for hair loss is intended for adult men with male pattern hair loss. It should not be used by women, children or adolescents.

You should speak to a prescriber before taking finasteride if you:

• have a history of depression or suicidal thoughts
• have ongoing sexual dysfunction
• have breast lumps, breast pain or nipple discharge
• are trying to conceive or have fertility problems
• have liver problems
• are taking other medicines that may affect sexual function or mood
• have previously had an allergic reaction to finasteride

You should stop taking finasteride 1mg and contact a doctor as soon as possible if you develop depression or suicidal thoughts.

You should also seek medical advice urgently if you develop symptoms of an allergic reaction, such as swelling of the lips, face, tongue or throat, breathing difficulty or a severe rash.

For sexual side effects, breast changes, testicular pain or fertility concerns, speak to a doctor or pharmacist. They can help decide whether you should continue, pause or stop treatment.

You cannot completely remove the risk of side effects, but you can reduce risk by using finasteride appropriately.

Before starting treatment:

• read the patient information leaflet
• tell your prescriber about any history of depression or suicidal thoughts
• mention any existing sexual dysfunction
• disclose all medicines and supplements you take
• consider taking baseline photos so you can judge whether treatment is helping
• ask how long to try treatment before reviewing results

While taking treatment:

• monitor your mood and sexual function
• ask a partner or family member to watch for mood changes
• report side effects early
• do not take more than the prescribed dose
• review treatment if side effects outweigh the benefits

Further reading: Reducing the risk of finasteride side effects

Finasteride is used long term by many men for hair loss. For most men, it is well tolerated. However, long-term use still requires awareness of sexual, mood-related and breast-related side effects.

The decision to continue finasteride should be based on whether it is helping your hair loss and whether you are tolerating it well. If you are getting side effects, the benefit of keeping your hair may not outweigh the impact on your wellbeing.

A good review point is usually after 6 to 12 months. By this stage, you can assess whether finasteride is slowing shedding, stabilising hair loss or improving density.

For many men, finasteride is worth taking because it is one of the most effective treatments for male pattern hair loss. It can slow further hair loss and may improve hair thickness over time.

However, it is not suitable for everyone. If you have a history of depression, suicidal thoughts, significant sexual dysfunction or severe anxiety about side effects, you should discuss this carefully with a prescriber before starting.

The best approach is informed consent: understand the benefits, understand the risks, monitor yourself properly and seek advice early if anything changes.

Finasteride is an effective treatment for male pattern hair loss, but it is not risk-free. The most important side effects to understand are sexual side effects, mood changes, depression, suicidal thoughts and the possibility that some sexual side effects may persist after stopping.

Most men tolerate finasteride well. However, you should only take it if you understand the possible risks, know what symptoms to look out for and feel comfortable discussing side effects with a healthcare professional.

If you are unsure whether finasteride is suitable for you, speak to a pharmacist or doctor before starting treatment.