High testosterone levels could be killing men by causing blood clots and heart failure, study claims

High testosterone levels could be killing men by causing blood clots and heart failure, study claims

  • University of New York and University of Hong Kong analysed 400,000 people
  • Showed definitive link between fatal diseases and the male sex hormone
  • Findings also have implications for men who take testosterone supplements
  • Controversially, experts suggest lowering testosterone as a form of treatment 

Having high levels of testosterone could be dangerous for men, scientists fear. 

Researchers found a natural abundance of the hormone in men is linked to blood clots, heart failure and heart attacks. 

The findings also have implications for men who take testosterone supplements to boost energy levels and sex drive, the experts warned.


Are men at risk? Testosterone – a naturally-occurring anabolic steroid – may cause major heart problems, such as blood clots and heart failure, in those with high levels

However, they were unable to prove whether testosterone directly causes the heart conditions – and have called for further trials.

Researchers at the City University of New York and the University of Hong Kong led the study, published in the British Medical Journal. 

They analysed data from 400,000 men and women, aged 40 to 75 years, from an existing study and the UK Biobank database.

The study team, led by Professor Mary Schooling, assessed the genes that predict testosterone levels and their links to heart problems.  


Testosterone is the male sex hormone and is mostly made in the testicles, but also in adrenal glands near the kidneys.

It causes the voice to deepen, body hair to grow and the genitals to become larger during puberty.

As well as affecting sex drive and sperm production, it also plays a role in developing strong bones and muscles.

Women also create small amounts of the hormone in the ovaries and adrenal glands.

Low testosterone in men can cause erectile dysfunction, low sex drive and muscle weakness.

Heart conditions were identified from self-reports, hospital and death records, and results were validated using data from another large study.  

The researchers found that in men, high natural testosterone was clearly associated with a higher risk of blood clots, heart failure and heart attack.  

The same associations were far less obvious in women, who have very low levels of testosterone.

The researchers concluded testosterone ‘is detrimental for thromboembolism, heart failure, and myocardial infarction, especially in men’.

And they say further evidence is needed to clarify whether the findings are relevant to the higher rates of these diseases in men than in women.

They also suggest that it may be worth considering whether existing treatments that lower testosterone could help protect against these conditions.  

Some 69,000 women have a heart attack in the UK every year, compared to 119,000 men, according to statistics.


The NHS and Government say their new 10-year plan, announced in early January 2019, will save up to 500,000 extra lives over the next decade.

This is how they hope to do it: 

  • Using more high-tech treatments and diagnostic testing, including computers with artificial intelligence, to prevent 150,000 heart attacks, strokes and dementia cases
  • Putting 100,000 people with heart complaints through healthy living and exercise programmes every year, with a view to preventing 23,000 premature deaths 
  • Improving diagnosis to catch 75 per cent of all cancer cases ‘early’ while they’ll still respond well to treatment – the figure is currently 50 per cent
  • DNA testing for around 30,000 people who have dangerously high cholesterol due to genetic causes
  • Investing an extra £4.5bn a year in primary and community care, reducing pressure on hospitals
  • Investing an extra £2.3bn a year in mental health services and giving help to an two million more people suffering from anxiety, depression and other mental health problems

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