Does finasteride cause erectile dysfunction?

Finasteride may cause erectile dysfunction, but it’s quite rare with the low dose used for male hair loss — and in clinical trials, it was usually reversible. Less than 2% of people who take 1 mg of finasteride experience ED.

Read on to better understand the connection between finasteride and erectile dysfunction, and what you can expect in terms of recovery if you experience this rare side effect.

Yes, finasteride can cause erectile dysfunction, but it’s a rare side effect when taken for hair loss. In clinical trials of Propecia, 1.3% of men on finasteride 1 mg experienced ED, compared with 0.7% of men taking a placebo. 

Finasteride may also cause other sexual side effects, including reduced sex drive and decreased volume of ejaculate. Like ED, these side effects are rare, affecting less than 2% of men in clinical trials.  

The risk of ED with finasteride may increase with the dose and the age of the person taking it. ED is a more common finasteride side effect when taken for BPH, which requires a higher dose (5 mg), as opposed to the lower dose prescribed for hair loss (1 mg). Keep in mind that men with BPH are usually older and already at higher risk for ED.

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Finasteride ED in BPH vs. hair loss 

In Proscar’s clinical studies, about eight out of 100 men taking finasteride 5 mg reported trouble getting or keeping an erection  in the first year, compared to about four out of 100 taking a placebo. In years 2–4, the rate of impotence in both groups was the same — about 5%. New reports of ED became less different between the finasteride and placebo groups over time.. 

Also, the fact that ED rates evened out between the finasteride and placebo groups after the first year could suggest that the benefits of treating BPH — like relieving urinary symptoms — may help improve or stabilize sexual function over time. But the reason the difference between the finasteride and placebo groups became smaller after the first year is not clear.

One of the largest studies of finasteride side effects had similar findings. Researchers analyzed 17 trials involving over 17,000 men. Some studies looked at finasteride or dutasteride (a similar drug) for BPH, while others focused on hair loss. The risk of sexual side effects like ED and low sex drive was higher in the BPH group but not clearly increased in the hair loss group. Another smaller study on finasteride for hair loss found no link to  ED. 

Overall, studies of finasteride for hair loss have produced somewhat mixed results. Randomized trials and systematic reviews suggest that finasteride 1 mg can modestly increase the risk of sexual side effects compared with placebo.

Why might finasteride cause ED?

So, why does finasteride cause ED in some men? Researchers think it has to do with the way the drug affects androgen (sex hormone) levels. 

Finasteride is a 5-alpha-reductase inhibitor.It stops the conversion — of testosterone into dihydrotestosterone (DHT). DHT plays a role in both male pattern baldness and BPH — it contributes to prostate growth and can cause susceptible scalp hair follicles to gradually miniaturize in men with androgenetic alopecia. In people who are genetically susceptible to male pattern hair loss, DHT can cause scalp hair follicles to shrink over time, leading to progressively thinner hair.

Finasteride erectile dysfunction is an uncommon but possible side effect of finasteride. In clinical trials, ED affected 1.3% of men taking 1 mg of finasteride for hair loss and 8.1% taking 5 mg for BPH during the first year. Rates of sexual side effects decreased with longer treatment for both.

Although sexual side effects resolved in many men and new reports became less common over time, longer-term studies suggest otherwise. One four-year study of older men with BPH, sexual function declined over time, including placebo. Finasteride was associated with a small worsening in ejaculatory function compared with placebo, but finasteride alone did not significantly worsen erectile function compared with placebo. 

However, it’s worth pointing out the men in this study were older — 62 years old, on average — and ED becomes more common with age. Also, these numbers were based on an 11-question survey that asked men to rate their sexual function within the last 30 days, which may not reflect their overall erectile function within the four years they took finasteride.

Finasteride-related ED can affect men of all ages, including young men in their 20s and 30s. More broadly, ED is not all that uncommon. Among a survey of men aged 18--87, roughly one in four reported ED. ED becomes more common with age, but a variety of factors can cause and contribute to ED, including:

• Depression

• Performance anxiety

• Diabetes 

• Obesity

• Neurological conditions like multiple sclerosis

• Traumatic injury to the pelvis or spinal cord

• High cholesterol

• Stroke

• Smoking

• Medications like antidepressants, opioids, and those for high blood pressure

In many cases, ED is reversible, including ED caused by finasteride. In clinical trials, when men stopped taking finasteride, their ED stopped, too. Even among the men who initially experienced ED but continued taking finasteride, their ED usually reversed with time. By the fifth year of taking finasteride 1 mg, 0.3% or fewer men reported ED. 

Note: It’s not clear whether the ED went away on its own, or if it resolved because the men who experienced it sought treatment (ED is almost always treatable, as we’ll get into in the next section). It’s also possible that some of the men who experienced ED stopped taking finasteride and were not included in that fifth-year analysis.

Post-finasteride syndrome

Some men have reported persistent sexual and other symptoms after stopping finasteride, sometimes referred to as post-finasteride syndrome (PFS). Persistent sexual dysfunction is also included in finasteride’s postmarketing safety information, but PFS remains incompletely understood and its frequency and causes are uncertain.

Symptoms of PFS may include:

• Little to no sex drive 

• Erectile dysfunction

• Less ejaculate than usual

• Less satisfying orgasms

• Poor semen quality and infertility 

• Fatigue

• Muscle weakness, pain, or spasms

• Confusion

• Mental health symptoms have also been reported. Current finasteride labeling includes postmarketing reports of depression and suicidal thoughts or behavior.

It isn’t clear why or how often PFS happens. Similar long-term side effects have also been reported with other 5-alpha reductase inhibitors, including dutasteride.

If you have any lingering side effects after stopping finasteride, tell your healthcare provider. They can help determine the cause and recommend ways to manage your symptoms. Call 911 or seek emergency help right away if you have thoughts of harming yourself.   

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The recovery timeline for ED after stopping finasteride can vary from person to person. Finasteride has a half-life of about six hours. This means blood levels fall relatively quickly after the medication is stopped, but that does not necessarily predict how quickly sexual side effects will improve.In clinical trials, sexual side effects generally resolved after stopping finasteride, although persistent symptoms have also been reported.

Finasteride erectile dysfunction recovery can also depend on other factors that may be contributing to your ED, including other health conditions and lifestyle habits. Getting treatment for these other conditions and making changes such as losing weight or quitting smoking can take time, which means it may take longer for your ED to improve as well.

If you experience ED while taking finasteride, you have plenty of options for treating it, without necessarily having to stop finasteride. Consider these proven options for treating ED: 

• Ask your healthcare provider about ED medication: Oral ED medications like Viagra (sildenafil) and Cialis (tadalafil) have an overall success rate of 76%. Ro also offers alternative formulations like Daily Rise Gummies containing tadalafil, and Ro Sparks, a dissolvable lozenge that contains the same active ingredients as Viagra and Cialis. These compounded formulations are not FDA-approved.

• Eat a healthy diet: Greater adherence to a Mediterranean-style diet has been associated with a lower risk of developing ED. The Mediterranean diet limits the consumption of red and processed meats, instead focusing on vegetables, fruits, nuts, legumes, and healthy fats from fish.

• Exercise regularly: Exercise is recommended for several conditions linked to ED, such as obesity, high blood pressure, and heart disease. Research shows that 40 minutes of moderate-to-vigorous aerobic exercise four times a week can significantly reduce ED symptoms within six months.

• Take care of your mental health: Depression is strongly correlated with ED, and dealing with ED can be stressful on its own, further worsening depression and performance anxiety.  A therapist can help you develop techniques for reducing anxiety, improving your confidence in the bedroom, and strengthening your relationships with your sexual partners. 

• Quit smoking: Smoking is heavily associated with ED. In one study, erectile function improved after one year in at least 25% of men who quit smoking, while no improvement was seen among men who continued smoking. 

Some men who experience ED with finasteride choose to stop taking the medication. But there are many ways to treat ED without stopping treatment for BPH or hair loss. Always consult your provider before stopping a drug like finasteride. They may be able to recommend other options forED, including a different treatment for BPH or hair loss.

ED is not the only possible sexual side effect of finasteride. Other sexual side effects include reduced libido and decreased ejaculate. These affect 4%–6% of men taking Proscar (finasteride 5 mg) for BPH, and 1%–2% of men taking Propecia (finasteride 1 mg) for hair loss. 

Other nonsexual side effects of finasteride in men include breast enlargement, breast tenderness, and rash. 

Reports of sexual side effects generally became less common with longer treatment in clinical trialsWhile ED, sex drive, and ejaculation problems tend to become less common, breast-related side effects and rash remained uncommon but were reported somewhat more often during later years of the BPH study.These side effects may be more common among men taking finasteride for BPH ( Proscar) than for hair loss (Propecia). The dose of finasteride for BPH is higher than for hair loss: 5 mg vs. 1 mg

But more research is needed to fully understand the effects of finasteride on sexual function. 

If you’re taking finasteride, you may be wondering if there’s anything you can do to prevent sexual side effects in the first place. Try these tips:

• Live healthy: ED becomes more likely with age, but other health factors, such as obesity, alcoholism, diabetes, and smoking, can also increase your risk. To reduce your risk of ED, adopt a healthier lifestyle that includes eating well, exercising, limiting alcohol, and avoiding smoking or recreational drugs.

• Take finasteride as prescribed: The typical finasteride dosage is one tablet by mouth once daily. Taking more finasteride than prescribed won’t make it work faster or better, so take the medication exactly as directed.

• Talk to your healthcare provider: If you’re worried about experiencing ED or other sexual side effects of finasteride, talk to your healthcare provider. They can give you more tips to reduce your risk, based on your personal health situation. 

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If you’re worried about taking finasteride due to potential sexual side effects, the good news is ED was uncommon in clinical trials of finasteride 1 mg  and resolved on its own or with treatment. Even among men who develop ED, most see improvement without needing to stop the medication. Still, it's important to be informed and talk to your provider if you have concerns.

• ED is rare but possible when taking finasteride. In clinical trials, ED was reported by 1.3% of men taking finasteride 1 mg for hair loss. In a separate BPH study, it was reported by 8.1% of men taking finasteride 5 mg during the first year and 5.1% during years 2–4.

• Most men recover from finasteride-related ED. Erectile function often returns after stopping finasteride or even while continuing it, according to clinical trials. However, some men may develop a persistent form of ED that lasts years.

• Recovery timelines vary. For some, ED may resolve quickly; for others, especially those with other health issues, recovery may take longer.

• Treatment is available. ED medications like Viagra or Cialis, along with lifestyle changes like exercising more and quitting smoking, can help treat ED.

If you notice you start losing erections while taking finasteride, or if you want to get ahead of any possible side effects, make an appointment with your healthcare provider. They can offer more personalized guidance and treatment options based on your individual health situation.