Finasteride is one of the common drugs on the market for male baldness – but recently its users have reported worrying side effects. Photo / 123rf
Finasteride is one of the commonest drugs on the market for male baldness – but recently its users have reported worrying side effects.
A few years ago, James* was at the pub with colleagues when a female co-worker walked behind him to get to the bar.
“James, you should just shave off all your hair,” she offered, “because you’re balding. So it’ll look better”.
It was the first time James, who was 30 at the time, had given much thought to his hair.
Sure, he’d noticed a bit of thinning on top but it hadn’t bothered him.
Then he and his girlfriend broke up and James entered the world of dating apps, where everyone seemed to care about his appearance – and hair.
He found himself googling celebrities such as Wayne Rooney and David Beckham, examining not only their hair but also whether their fathers were bald. Then targeted social-media advertising got its claws into him.
Months later, James was on a health website called Hims, browsing products that promised to regrow hair. “No GP visit required,” it said.
So James signed up, answered a set of questions and received an email saying a hair-loss serum had been approved by a healthcare provider.
It was half-price for the first three months – £57 (NZ$120) for three 60ml bottles.
One of the active ingredients was a drug called finasteride, which was developed to treat benign prostate enlargement but has also been prescribed for hair loss in men since the 1990s.
The United Kingdom’s NHS lists its main side effects as ‘losing interest in sex and difficulty getting an erection’.
But the Hims website, which nods to these and further side effects, adds: ‘The [sexual] side effects are usually temporary and disappear when the treatment is stopped.’
It also notes that they were observed in trials of oral finasteride, and there is ‘no conclusive evidence that the same symptoms are likely to occur’ with topical use.
James clicked ‘buy’.
Today James has a beard and a fairly healthy head of hair that is thinning only slightly on top.
He is an affable, smiling 34-year-old man: Easygoing, articulate, thoughtful. But over the past 24 months, he has experienced what he calls a ‘living nightmare’ of sexual dysfunction.
The first time he massaged the serum on to his head, it felt a bit tingly.
Soon after his libido – which had always been healthy – increased.
Both seemed like positive results.
But about three weeks later, he woke with an intense ache in his testicles. He considered making a doctor’s appointment but by the next day it had disappeared.
Not long afterwards, however, his libido dropped.
By now he was dating actively and at times found that he wasn’t able to get an erection at all.
“Nothing worked. I thought I must just have been nervous, and actually, that I don’t like casual sex.”
Still, it was mildly alarming.
Three months after he’d started using the serum, his prescription ran out and James decided not to renew it; the improvement to his hair hadn’t been as great as he’d hoped.
But even after stopping, his libido remained low.
“[Sex] was weird. I felt a sort of dissociation and I didn’t really find it fun.”
That October, he decided to restart hair-loss treatment, this time trying a spray that also contained finasteride, prescribed through the same website.
“And I was fine for a long time.”
But the following November, when his supply was running out, he decided not to replace it. Again, he didn’t think the scant improvement was worth the money.
Only this time when he stopped, the wheels well and truly came off.
In the weeks before stopping, he observed that he was starting to become irrational, getting more worked up than usual about minor issues.
He put it down to the stress of a new job he’d just started.
Then, he found himself crying often.
Two days after stopping, he recalls feeling as though tiny creatures were biting his penis and testicles internally.
He took an STD test, which was negative. The pain stopped after a day but the testicular ache continued for another month.
By this point, he was also urinating more frequently, sometimes 10 times a night, and he had stopped being able to get an erection.
“It was like a switch had been turned off in my brain.”
Almost more alarming was the physical change.
He says that his penis “narrowed in a way I’d never seen before” and that it developed spidery veins, as well as an odd bend in the shape.
Then, at a party he had a panic attack; a friend calmed him down but he found himself absolutely freezing, despite wearing many layers of clothing.
Concerned, he took a home blood test for testosterone, which showed his levels were 10.4nmol/L, lower than the normal range for his age (12.4-17.3nmol/L).
His triglyceride level (a type of blood fat) was 4.4mmol/L – far higher than the normal range for his age (0.45-1.8mmol/L).
He went to the GP, who told him, “We know finasteride can mess with hormones”.
It was the first time he had any inkling that his hair-loss treatment might be in any way connected.
The aching and low libido continued, so he booked an appointment with a private urologist in London’s Harley Street, who did a second testosterone test.
It showed his levels had fallen to 8.82nmol/L: close to the range suggesting hypogonadism, the medical term for testosterone deficiency.
James was prescribed Clomid, a drug used to treat some types of infertility in women, but which also increases the luteinizing hormone in men, which supports reproductive health.
But James, who stresses that he was not depressed, says his libido remained low.
He went to see another Harley Street urologist, David Ralph, for a second opinion; Ralph advised him to continue on the Clomid.
Three weeks later, things were looking up a little. James’s testosterone levels had shot back up, his interest in people had returned, and he had more energy, though he says that his libido hasn’t fully returned and that his penis shape still looks different to before.
But the struggles had lasted two years.
He puts them squarely down to the serum and spray that he used, or more specifically one of the active ingredients within them: Finasteride.
Male pattern baldness is the most common type of hair loss, affecting some 6.5 million men in the UK alone. The precise cause isn’t known but age, hormones and genetics can all play a part.
Finasteride has long been used as a treatment. Part of a family of drugs known as 5-alpha reductase inhibitors, it works by stopping testosterone being turned into dihydrotestosterone (DHT), another hormone which can both stop hair growth and cause the prostate to grow bigger.
Pharmaceutical company Merck developed finasteride as a treatment for hair loss and in 1997, the US Food and Drug Administration (FDA) approved the use of its drug Propecia, a tablet containing finasteride.
It proved popular: sales reached $447 million in 2010, shortly before Merck’s patent expired. In NZ, while it can be prescribed for hair loss in men, it is not funded so must be paid for.
But trials had found that about 3.8 per cent of men experienced sexual side effects, including difficulty getting erections or ejaculating, compared with 2.1 per cent of those in a placebo group.
Further trials found one patient whose erectile dysfunction persisted for more than six months after he stopped taking Propecia.
By 2009, 200 cases of depression in men taking the drug had been reported.
The following year, the FDA approved a warning added to the drug’s packaging about the risk of depression, and two years later another about the risk of persistent sexual dysfunction. In 2022, suicidal thoughts were added.
At that point, there had already been lawsuits from people alleging that Propecia had caused them to suffer from persistent sexual side effects after they stopped taking it.
By 2016, an estimated 1400 people had filed lawsuits related to Propecia against Merck. Some were settled out of court for a combined lump sum of $4.3 million.
In the years since, other men have shared stories of experienced symptoms during – and after – taking the drug, with some referring to these as post-finasteride syndrome (PFS). Online support groups are littered with such stories – men who claim to have lost their jobs, seen their health deteriorate and their marriages break down, in their view, as a result of PFS.
James says that one of the Harley Street doctors he visited told him: “You have all the symptoms of the syndrome”.
And yet although some doctors may recognise it, PFS is not officially recognised by the medical profession in the US or the UK.
A 2019 editorial in The BMJ called PFS ‘ill-defined and controversial’. There are no known effective treatments.
The long list of symptoms can include brain fog, sleep disturbance, anxiety and muscle loss, as well as shrinkage of the penis and testes, anhedonia, weakened erections, an inability to ejaculate and testicular aching.
The problem, explains Professor Pierre-Marc Bouloux, director of the Centre for Neuroendocrinology at University College London, is not only that finasteride is easily and cheaply available via the internet, but the range of symptoms is so broad that it is not easy to ascertain which ones are linked to the drug as opposed to an underlying conditions.
He says he has treated many men reporting associated symptoms.
“There is clear evidence that the symptoms of some patients who have been exposed to finasteride are unexplained,” he says, “and the pharmaceutical industry has been extremely reticent to explore this”.
He points out, however, that it is difficult to know what proportion of the patients had premorbid tendencies to, for example, depression.
“Add in relational difficulties plus premature hair loss and you could have a perfect storm to make some people more vulnerable.”
Merck has previously denied allegations in court filings that accused the company of not adequately warning patients of the drug’s possible side effects and their duration.
It has also said it “stands behind the safety and efficacy of Propecia”, and that it “works continuously with regulators to ensure that potential safety signals are carefully analysed and, if appropriate, included in the label”.
Hims, the website through which James was prescribed hair-loss treatments, told The Telegraph: “Quality and safety is integral to our mission and only licensed medical professionals who have successfully completed a rigorous vetting process are able to provide care through our platform… All customers have access to follow-up appointments and continued care”.
Rowan*, an operations manager from Tyneside, was prescribed Propecia privately by his GP in 2000. He was 32 at the time and had noticed a tiny bald spot on his crown.
Weeks after first taking the drug, he was in the garden of his home, about to go on a night out, when he experienced what he describes as “a bolt of lightning panic like I’d never experienced in my life”.
He cancelled his night out, told his manager he wouldn’t be at work the next day and went to bed, hoping the feeling would pass. It didn’t.
In the weeks, months and years that followed, Rowan’s life changed completely. He went back to work, but felt his interactions with others had changed: He was nervous, conversations felt forced.
He says he struggled with certain cognitive tasks, like spelling. He’d always been a keen gym-goer but now, when he went, he noticed he’d lost strength.
His sex drive dropped off a cliff, and over time he developed what seemed like breasts, despite losing weight.
His skin dried out, his teeth fell out and his eyes got sore. But neither he nor medics made any connection to finasteride, so he continued to take it.
Then, in 2017, he read an article about PFS. It struck a chord. “I was elated at first – I’d found the cause of all these health issues,” he says.
“Then I started to research it. I read obituaries, about suicides, on online forums I found places of desperation for guys trying to get relief.”
He stopped taking finasteride immediately.
He went to his GP, who said PFS wasn’t a real thing.
“I was met with cynicism at every turn,” he recalls.
Meanwhile, his health continued to deteriorate. He is 57 now.
He lists other symptoms he lives with: A receded jaw and gums; lost tissue and subcutaneous fat; allergies developed to a myriad of foods; and poor sleep.
He’s had suicidal thoughts too. His marriage is, he adds, “in ruins”.
In 2018 he reported his symptoms to the UK’s Medicines & Healthcare products Regulatory Agency (MHRA), which approved finasteride for use in male hair loss in 1999.
He says he has since sent “numerous emails”.
“I got replies… Anything outside of what they are prepared to recognise was and is played down, stating it is not proven.”
It was, he says, like “banging my head against the wall”.
Certain potential side effects of Propecia have long been listed in the product information, available on the MHRA website.
Then last year, it launched an investigation into the safety of oral finasteride after a three-fold rise since 2020 in men reporting serious side effects including depression, insomnia, low libido and erectile dysfunction. (Topical finasteride is not yet licensed by the MHRA.)
In April it announced it would be introducing a patient alert card to increase awareness among men taking the drug about potential psychiatric and sexual side effects.
Before starting to take the drug, patients must inform their prescriber of any personal history of depression or suicidal thoughts, and those taking the drug who develop such thoughts should immediately stop treatment and consult a doctor.
Asked why the investigation was not launched earlier, the MHRA told The Telegraph: “[There] are known side effects of finasteride and the information is already included in the product information. [A] review was initiated in response to enquiries from patients concerned about the apparent lack of awareness among healthcare professionals and patients of these side effects. A patient alert card will be introduced into the finasteride pack this year to raise awareness of these risks”.
Organon, the current marketing authorisation holder for Propecia and one of the manufacturers of finasteride, also told The Telegraph: “Organon has worked closely with the MHRA in its most recent safety review of finasteride… Alongside all other manufacturers of finasteride, we are working to introduce a patient alert card to raise awareness of potential adverse effects”.
Dr Robert Stevens, who qualified as a GP, runs The Men’s Health Clinic in Dorset, which specialises in diagnosing and treating testosterone deficiency. He disagrees that the side effects of finasteride are rare, despite the evidence. Taking it to treat baldness is, in his view, “absurd – it’s scandalous really”.
“We are getting an increasing number of men presenting with concerns about PFS,” he adds. He is not optimistic about finding an easy solution.
“Realistically, there’s no cure,”' he explains.
He suggests normalising hormone levels, with careful administration of testosterone and human chorionic gonadotropin (hCG), a hormone produced by the placenta during pregnancy. He adds that this may be a lifelong therapy.
Mark*, 44, has been seeing Stevens for three years. Prior to that, he had been taking finasteride, on and off, for about a decade, after his hair started to thin.
He’d always had a high libido, which gradually reduced. He says the timeline coincided with taking the drug.
“It really affected my confidence in being able to get into longer-term relationships.”
Like James, he believes his symptoms are consistent with PFS.
Now he takes a daily injection combining testosterone and hCG in microdoses.
This has changed everything.
“I can have a healthy sex life I don’t have anxiety about which is fantastic.”
It has “given me a normal life back”.
As for James, things are not entirely back to normal. He still has little sex drive. His beard grows at roughly a tenth of the speed it did before and he has lost his hair on his shins.
And yet he is hopeful: His experience on Clomid suggests his body is receptive to hormonal regulation. Days after we meet he goes to see Stevens, who prescribes daily injections of hCG; he may also start testosterone in the future.
He feels he has made progress since the dark days at the start of this year.
But he has certain regrets. “I feel like if anyone reads this they need to know that for some men, persistent means permanent,” he says.
“I’m 34 and the next thing I wanted to do in life was get married and have kids. I feel like that’s been cut off. I feel like a big part of my identity has been killed. I could have had a really great life and done that thing I wanted…
“If I’d known those things, I never would have taken that drug.”
*Some names have been changed
For more information about Finasteride in New Zealand, go to healthify.nz/medicines-a-z/f/finasteride
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