To put it in Lord of the Rings terms, you’ve heard whispers of a nameless fear. But if sexual side effects are really an issue, why are millions of men still taking finasteride? Let’s dig into the research.
Not all clinical studies are created equal, so we’ll only be quoting double-blind placebo-controlled trials in this article. These are trials where both the researcher and subject don’t know who is receiving a placebo—a technique used to eliminate bias.
Double-blind placebo-controlled studies actually show us that there is little to no relationship between finasteride and most sexual side effects (Source). However, in three controlled clinical trials of 12-month duration, the FDA’s reports that approximately 0.3% of men discontinue use of finasteride due to reported sexually adverse effects. This is a tiny amount for a prescription medication—and side effects go away if you stop treatment.
It's easy to blame finasteride for sexual dysfunction in online opinion pieces, but hard to blame it in controlled clinical trials.
To understand the side effects, you need to understand how finasteride works. Finasteride decreases DHT, a form of testosterone which is not used for sexual function in adulthood. Finasteride then increases normal testosterone levels by 5-15% which improves both sexual function and mood (Source).
In a double-blind placebo-controlled study using nocturnal penile tumescence (NPT) as an objective method of assessing erectile function, 5mg of finasteride failed to suppress consistent sleep-related penile erections. This means that when taking 5 times the dose used for male pattern hair loss (MPHL), researchers concluded finasteride did not affect erections (Source).
What’s more, in a double-blind placebo-controlled trial in 2003, the placebo group (group NOT taking finasteride) reported more sexual dysfunction post-treatment than the group actually taking finasteride (Source).
Finally, a 2016 meta-analysis of 17,494 subjects from 17 randomized control trials found finasteride does not cause ED when taken to treat MPHL and only sometimes causes a small decrease in semen volume (Source).
It's highly probable that ED and loss of libido are not caused by finasteride at all.
Studies suggest most sexual dysfunction from finasteride comes from either a nocebo effect (where worries about sexual dysfunction are what cause it), or simply a separate cause of ED, which affects 18.4 percent of U.S. men age 20 and older regardless of whether they take finasteride. Many men start losing their hair during the same stage of life where they start losing their libido—with the reasons behind it being broad—everything from stress & anxiety to relationship issues and lower testosterone.
The mental-health reasons behind sexual dysfunction in men are why it's easy to blame finasteride in online opinion pieces, but hard to blame it in controlled clinical trials.
It’s been well documented that the overall incidence of sexual dysfunction is higher in men who are focused on sexual side effects compared to men who are not (Source). Fear-mongering, both in the media and online, are the key causes of this, and it’s been found that the frequency of consultations for sexual side effects from finasteride parallels the respective media coverage (Source).
200% more men take finasteride now than in 2015, this is partly due to a better understanding of how low-risk, or even nonexistent most of the sexual side effects actually are. Even with a large fear campaign online, the overwhelming majority of men who take finasteride keep their hair without side effects of any kind. And since our enjoyment of sex is highly linked to how we feel about ourselves, improved hair often means an improved sex life.
