Finasteride is a popular hair loss medication. Always or often recommended by more than two-thirds of hair loss specialists, Finasteride is proven to create great results for those experiencing male pattern baldness [1].
But there are known side effects of Finasteride, which may deter some men from using it. That’s because Finasteride works by changing your hormone levels, including testosterone.
So does Finasteride lower testosterone, and if so, what impact does this have on your hair and body?
Finasteride is a medication that prevents enzymes in your body from converting testosterone to dihydrotestosterone. Dihydrotestosterone, or DHT, is the hormone that causes male pattern baldness, or androgenetic alopecia. So less DHT is good news for men with hair loss.
Both testosterone and dihydrotestosterone are androgens, or male sex hormones. They’re both necessary for organ development and function, especially in childhood. But there are key differences between the two:
By blocking the conversion of testosterone to DHT, Finasteride lowers your DHT levels. But in turn, this actually raises your testosterone levels [4]. That’s because less testosterone is being converted, so it remains in your body in its original form.
Research suggests that taking a 5mg Finasteride tablet each day can result in a drop of up to 93% in DHT, and a rise of up to 25% in testosterone [5]. (Bear in mind that 5mg isn’t a typical dose for treating hair loss — most men take 1mg of Finasteride a day for this purpose).
Erectile dysfunction is a known side effect of Finasteride, and it’s associated with low testosterone levels. So why does it happen if Finasteride increases testosterone?
DHT is the active androgen that helps you maintain an erection. So despite the increase in testosterone, the reduction in DHT may reduce your ability to get or maintain an erection.
Fortunately, erectile dysfunction is a rare side effect, impacting only 1.3% of Finasteride users [6].
No. Stopping Finasteride will increase DHT levels, but it won’t increase testosterone. In fact, your testosterone levels will probably dip: more testosterone is converted to DHT, so there’s less testosterone circulating.
When you stop taking Finasteride, hair loss is likely to resume. If you want to stop taking Finasteride without losing your hair, you might consider switching to topical Finasteride, which can maintain your hair while reducing the risk of side effects [7].
Some research has linked Finasteride with reductions in body mass index (BMI) in men [4]. So does this mean Finasteride inhibits muscle growth?
The research is limited, but one study has shown that Finasteride didn’t inhibit the increase of muscle mass in people taking testosterone enanthate (TE) [8]. While the musculoskeletal outcomes were the same in those taking Finasteride with TE and those just taking TE, Finasteride didn’t prevent men from gaining muscle.
Testosterone enanthate is an artificial anabolic steroid, which makes it a key contributor to these muscle gains. However, it should be used with caution. Speak to your doctor before considering the use of TE to build muscle.
Yes, it’s usually safe to take Finasteride alongside TRT therapy. Both treatments will increase your testosterone levels, but TRT also increases your DHT levels. Finasteride may reduce DHT levels, but it’s unlikely to significantly affect the outcome of TRT [8].
TRT is usually prescribed to those who have low testosterone levels, so most people’s testosterone levels will stay within the normal range even when taking both testosterone replacement drugs and Finasteride.
A rise in DHT levels can be beneficial for some patients, so weigh up the pros and cons of taking Finasteride alongside TRT.
To be on the safe side, track your testosterone and DHT levels throughout your treatment.
Finasteride is a safe, effective drug for male hair loss. Finasteride for transgender patients may sometimes be recommended, too. Studies show it can reduce crown hair loss by 83% and slow frontal balding by up to 70% [9].
But is it the right treatment for you? It could be, if:
Take a look at these Finasteride results to help decide if this is the right treatment for your hair loss.
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