Stone had known there was a small possibility of reduced libido and erectile dysfunction (between 1 per cent and 2 per cent), but he didnβt know that the drug might be linked to his fertility struggles.
Finasteride is prescribed at higher doses to treat enlarged prostates and has been known to mildly affect sperm counts. But Dr James Kashanian, a urologist and the director of male sexual health at Weill Cornell Medicine, said the drug has also βsignificantly affectedβ some patientsβ sperm quality, even at 1 milligram, the dose typically prescribed for hair loss.
Unlike with other side effects of the drug, itβs not clear how common reduced sperm counts are, and much of the data is anecdotal. While some doctors say that it can be a significant problem, especially among men already struggling with fertility issues, others say it plays a relatively small role.
Still, many young men are not aware of any potential risks, said Dr Mary Samplaski, a urologist and the former director of male infertility at the Keck School of Medicine at the University of Southern California.
Will Stone had been prescribed finasteride for hair loss through the US telehealth company Hims & Hers. A senior vice president at the company said it provides information about finasteride when patients are prescribed it and includes a warning on its website about infertility and poor sperm quality.
Faced with a choice between a full head of hair and increasing chances of becoming a parent, some men are embracing hair loss.Credit: iStock
In most cases, fertility issues seem to reverse within a few months of going off the medication and there is no evidence it causes birth defects. In Stoneβs case, he stopped taking it the day his urologist told him to. When he tested again 10 weeks later, his sperm count had jumped to 250 million per millilitre, a 125-fold increase.
A βMale Contraceptiveβ?
In 1999, the first peer-reviewed study to look at finasteride and sperm quantity found no effects. But a small 2013 study, led by Samplaski, focused specifically on 27 men dealing with infertility issues while taking finasteride. Researchers asked them to go off the drug for three months, the amount of time it typically takes for a new population of sperm to form. When the men were retested after going off finasteride, they registered an 11-fold increase in sperm counts on average.
Researchers suspect that the reason for the decline in sperm count is that the medication can shift the balance of hormones in the body, said Dr Scott Lundy, the program director of urology at the Cleveland Clinic. It does this by suppressing the conversion of testosterone to dihydrotestosterone, or DHT, which has been found to lead to baldness.
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For some people, disrupting hormonal ratios can create fertility issues. βA lot of people donβt know that testosterone is a male contraceptive,β said Dr Kirk Lo, a urologist at Mount Sinai Hospital in Toronto who worked on the study with Samplaski.
However, there are very few high-quality studies looking at finasteride and sperm counts, and not every doctor considers it an important factor in fertility. Dr Kian Asanad, the director of the USC Fertility and Menβs Sexual Health Centre, says he couldnβt recall a case when taking a patient off finasteride solved their fertility issues independently.
βI keep it in the back of my mind as a possible factor, but I would say itβs a less common thing.β
In the US, Kashanian says he has had more conversations about finasteride in recent years as more men have come in seeking treatment for infertility.
Dr Marc Goldstein, the surgeon-in-chief of male reproductive medicine at Weill Cornell Medicine, agreed and says that after he lays out the risks of taking finasteride while trying to conceive, some patients will choose to stay on the medication. βVanity reigns supreme,β he says.
But others, like Stone, are happy to go off the hair treatment. After his sperm count rebounded, last year he and his wife had a healthy baby boy. He has no plans to go back on finasteride any time soon.
βIβd have gladly lost every hair on my head to have the kid we have now,β he says.
This article originally appeared in The New York Times.
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