The daily pill Donald Trump takes to combat baldness cuts the risk of developing prostate cancer by a quarter, a major study has found.

Results of a 20-year study published today revealed the drug Finasteride has a major preventative impact on prostate cancer.

The pills are already widely taken in the UK and the US to combat male pattern baldness.

But the new study suggests they could also become the first medication to prevent prostate cancer before it strikes, in the same way as statins are used to prevent heart attacks.

Donald Trump is one of millions of men who take the drug for hair loss. But Finasteride is also used to decrease prostate size and possibly help to prevent prostate cancer. There was some controversy over whether the drug increased the risk. But a new study by Texas researchers found it to be safe and effective

The Daily Mail is campaigning for an urgent improvement of prostate cancer treatments and diagnosis, which are lagging years behind other diseases such as breast cancer.

Researchers at the University of Texas today said that men at high risk of prostate cancer - such as those who elevated levels of 'PSA' proteins in blood test - should be prescribed the drugs to lower their chances of developing the disease.

Study leader Dr Ian Thompson, whose team have tracked nearly 19,000 men since 1997, said: 'Finasteride is safe, inexpensive, and effective as a preventive strategy for prostate cancer.

'Doctors should share these results with men who get regular prostate-specific antigen [PSA] tests that screen for the presence of prostate cancer.

'The drug will have its greatest effect in this group of men.'

More than 3million prescriptions of Finasteride are already issued every year by the NHS in England – and many more are bought privately to tackle hair loss. In the US, about 8million a year take it for prostate issues, and 1.2million for hair loss.

As well as being used to prevent baldness the drug is also prescribed for enlarged prostate, a benign but very common problem which causes repetitive night-time visits to the bathroom.

The drug works by blocking the action of hormones such as testosterone.

FINASTERIDE'S LINKS TO MENTAL ILLNESS Finasteride belongs to a class of medications known as 5-alpha-reductase inhibitors (5ARIs). 5ARIs have come under increasing scrutiny in recent years by regulators in the United States and Canada because of a possible link to mental health issues, according to the researchers. Researchers at Western University examined finasteride and dutasteride, another 5ARI, in 2017. 'There wasn't a lot of good studies in this area, and it's a very common medication for urologists to use,' said lead author Dr Blayne Welk. Welk's team analyzed data from 93,197 men who were at least 66 years old when they received prescriptions for 5ARIs between 2003 and 2013, plus another 93,197 similar men who had never filled a prescription for a 5ARI. Overall, 5ARIs were not linked with an increased risk of suicide, the researchers reported in JAMA Internal Medicine. During the first 18 months, however, the men using 5ARIs had an 88 percent higher risk of harming themselves. That risk did not extend beyond 18 months. Men in the 5ARI group also had a 94 percent higher risk of depression in the first 18 months, compared to men not using these drugs. Beyond 18 months, the increased risk of depression fell to 22 percent. The type of 5ARI did not appear to significantly alter the results. Welk cautions that the actual risk of depression and self-harm is very low. If the drugs were actually causing these side effects - which this study wasn't design to prove - 'you'd need 470 men to take this medication for a full year to have a new case of depression,' Welk said. That number would have to be even higher to cause a new case of self-harm, since self-harm is less common than depression. 'It is a risk potentially and patients and physicians should be aware of it,' Welk said. Advertisement

But it has never been licensed to prevent prostate cancer because the US team's early results, published in 2003, suggested it increased the number of high-grade prostate cancers - a finding that resulted in a drug label warning posted by the Food and Drug Administration.

The new results, however, shows those fears were premature.

A paper summarising 20 years of data, published in the respected New England Journal of Medicine, found there was no statistically significant risk of aggressive prostate cancer - and the chance of developing all prostate cancer went down 25 per cent.

British experts last night greeted the findings with caution - stressing that the drug appeared to mainly stop the low-grade tumours that probably would not actually kill someone.

They pointed out that while the chance of getting prostate cancer at all fell significantly - the chance of dying was not cut at all.

But Dr Thompson argued that sparing men from low-grade prostate cancer is also hugely beneficial, because it means they do not have to go through gruelling surgery, radiotherapy and chemotherapy.

'There are significant negative consequences to patients' health and quality of life that can result from prostate cancer treatment, as well as to their finances and their peace of mind,' he said.

'If we can save people from surgeries, and scores of examinations and tests, and spare them from living for years with fear, we should.

'The best-case scenario for patients is prevention, and this trial has found an inexpensive medication that gets us there.'

Dr Matthew Hobbs, acting director of research at Prostate Cancer UK stressed the drug still comes with side effects - including depression and sexual dysfunction.

'Research into how to prevent prostate cancer is absolutely crucial if we are to reduce deaths from the disease, and forms a key part of Prostate Cancer UK's own research strategy,' he said.

'However, it is unlikely that the drug finasteride will be the magic bullet that many will be hoping for.'

He added: 'Although these findings appear to indicate that taking finasteride gave men a reduced chance of developing prostate cancer, it did not have an impact on the chance of developing the aggressive prostate cancers that go on to cause harm, and it also didn't reduce the number of deaths from the disease.

'Without evidence of these meaningful benefits, and knowing that finasteride also comes with side effects, we wouldn't advocate its use as a preventative for prostate cancer on the basis of this research.

'Finasteride is however an effective treatment for men with a non-cancerous enlarged prostate and its use in this setting should not change as a result of this research.'