Finasteride Side Effects: The Complete List

Finasteride, known in the UK under the brand name Propecia is the most effective medicine for treating male hair loss, preventing hair loss in 83% of men treated for two years1. But Finasteride doesn’t cause positive effects only. In a small proportion of men, it might cause side effects, one of which is a lower libido. Understandably, some men are concerned about taking finasteride.

In this article we’ll tell you what you need to know beforing hopping on finasteride to stop your hair loss.

What are the most common side effects of finasteride?

Finasteride, known as a 5-alpha-reductase inhibitor, is an oral medication and works by blocking the production of dihydrotestosterone (DHT). DHT is a male sex hormone that attacks the hair follicles on the head and cause them to shrink. Blocking DHT stops hair loss in more then 8/10 men, but may also cause unwanted effects, including 2:

  • Lower libido
  • Trouble getting or keeping an erection
  • Ejaculatory problems like premature ejaculation (PE)

How common are finasteride side effects?

Fortunately, finasteride's side effects are “rare” with 2% to 5% of men getting side effects. In one clinical trial around 3.8% of men taking the drug experienced side effects, versus 2.1% of men taking a placebo3. In men who continued taking the medication, the incidence of side effects declined over time, dropping to less than 0.3% in people taking finasteride for five years4.

Finally, a 2017 meta-analysis reviewed 17 studies involving nearly 18,000 men taking 5-alpha-reductase inhibitors. The study found that there wasn't a significant increase in sexual side effects in people taking the drug for hair loss. Only people taking them for enlarged prostates (which required a higher dose) experienced significant increases in sexual side effects (Fertig, 2017). This is because men who are using Finasteride for treating an enlarged prostate take 5mg while men taking it for hair loss only take 1mg.

As you can see, the dose for men taking Finasteride for BPH is five times higher than the dose of finasteride for hair loss, and so the chance of getting side effects is higher too. Makes sense right?

What to consider before taking finasteride

The chance of getting side effects is low, but it does happen. Some men aren’t bothered by having a lower libido, but for others it might not be so trivial. Even if it goes away with time.

So before taking Finasteride, it’s vital to perform a cost-benefit analysis. Getting a finasteride prescription might be the right choice if you find your hair loss bothersome and you aren't too worried about a low risk of sexual side effects.

Conversely, if you prefer to eliminate the risk of side effects, no matter how small, you might give Finasteride a pass. When in doubt, you can dm your healthcare provider to options that are available to you.

When weighing the pros and cons of finasteride, it is vital to note that once DHT has caused a follicle to die, it's impossible to revive. Finasteride is powerful but it doesn’t bring hair follicles back to life. So if you’re contemplating to take action, take action sooner then later. And not after you have already lost most of it.

What are the less common side effects of finasteride?

Other possible side effects of finasteride are less common but include:

  • Finasteride might affect your PSA-levels (prostate specific antigen). If you have a PSA test done, tell your healthcare provider you're taking finasteride .
  • Allergic reactions, including rash, itching, hives, and swelling of the lips, tongue, throat, and face
  • Testicular pain

Not all possible side effects are listed here. For more information talk with your healthcare provider.

How can I reduce the side effects of finasteride?

Avoiding side effects altogether is not possible. Finasteride works by lower your DHT. The benefit of this is that it stops hair loss in most men, but causes unwanted side effects in some. You cannot have one without the other. You either take the risk or don’t, but in that case accept the fact that you’re losing hair. it’s as simple as that.

There are some things you can do however to slightly decrease the chance of getting side effects: stick the prescribed dose. if you’re prescribed 1mg, don’t take 2mg, 3mg or 5mg thinking it will be beneficial because it will not. The studies have been done and 5mg is not more efficious than 1mg. Another thing: take it consistenly. Don’t skip doses. Finally: discuss any side effects with your provider, as some may be temporary and resolve with time.