I went from a dad bod in my 40s to a gym god in my 50s. People think I'm taking something... but it's all thanks to this natural testosterone-boosting method. Here's exactly how YOU can do it too

For Jason Smith, appearing shirtless on the cover of Men's Fitness in his mid‑50s was a proud moment – the culmination of years of discipline, consistency and hard work.

Less than a decade earlier, the father-of-one had been overweight and facing a stark health warning. Tests carried out by his doctor revealed high blood pressure, raised cholesterol and pre-diabetes, along with the very real prospect of developing fatty liver disease – all of which dramatically increased his risk of an early death.

'I was angry with myself,' Smith told the Daily Mail, recalling the moment he heard the news. 'The way I was living – how I ate and drank – was more like a college student than a father in his late-40s. I knew I was responsible for the state I was in.'

Determined to turn his life around, the UK-based business consultant overhauled his lifestyle from the ground up – ditching alcohol, transforming his diet and committing to regular exercise.

The results were so striking he went on to study to become a personal trainer with a focus on helping other middle-aged men regain their health.

So when Men's Fitness came calling in September 2025, it was a milestone moment. But not everyone was convinced.

Online critics were quick to question his transformation, with some accusing him of using testosterone replacement therapy (TRT) to achieve his physique – claims he strongly denies.

Their scepticism came amid a boom in the 'testosterone optimization' industry, with private clinics increasingly offering costly blood tests to check for levels of the male sex hormone and promoting TRT as a solution for men with fatigue, low mood, erectile dysfunction and weight gain.

Yet Smith, wary of side effects – which can include suppressing the body's natural hormone production – insisted he achieved his results naturally.

'I was aware of the whole TRT industry, but I knew I didn't need artificial hormones,' he said. 'I just had to make some changes.'

In fact, tests showed that from having borderline low testosterone, Smith, now 56, was able to more than double his levels simply by improving his lifestyle.

Experts say such transformations are not only possible, but pretty much expected in men who make sustained changes to their diet, exercise and sleep.

'There is a lot that men can do to improve their levels naturally,' Dr Jeff Foster, a physician specializing in men's health, told the Daily Mail.

'In many cases, low testosterone is driven by poor lifestyle – lack of sleep, excess weight, inactivity and stress. Fix those, and levels will often improve without the need for medication. Men whose levels are low because of their lifestyle tend to see the biggest gains.'

Dr Ashley Grossman, a consultant endocrinologist at Queen Mary University of London, specializes in treating patients with hormone disorders, including men with clinically low testosterone known medically as hypogonadism. This deficiency, he said, is often due to problems with the testes or the brain signals that control hormone production.

He told the Daily Mail the profile of patients seeking help has changed in recent years.

'There's been a massive increase in men coming to us after being tested privately, worried about their levels and asking for testosterone,' Dr Grossman said.

'In many cases, they don't have a true deficiency – and treatment isn't needed.

'Testosterone therapy is not benign. Used inappropriately, it can suppress natural production, cause infertility and put strain on the cardiovascular system.'

So what is testosterone, and why do levels fall?

Testosterone is a sex hormone produced by both men and women, although men produce far higher levels.

In men, it plays a key role in maintaining muscle mass, bone strength, energy levels and sex drive, as well as powering the changes seen in puberty.

Levels naturally decline with age – typically from the 40s onward – but for most men this gradual drop is modest and does not cause significant problems. However, modern lifestyles can accelerate that decline.

Factors such as excess weight, poor diet, lack of exercise, chronic stress and inadequate sleep can all push testosterone levels down further – sometimes into what is labelled the low or borderline range.

Guidance from the Endocrine Society and American Urological Association emphasizes that low testosterone should not be diagnosed on blood tests alone, but only when consistent symptoms are present and other causes – including obesity, depression and chronic illness – have been considered.

'For the vast majority of men, having low testosterone reflects low levels of health and fitness, especially over age 40,' said Dr Channa Jayasena, an endocrinologist and professor of reproductive endocrinology at Imperial College London.

'Testosterone levels fluctuate, so some men may be within "normal" levels but could still benefit from optimising their natural production.

'Only around two to three percent of men will have a clinical deficiency requiring TRT, the rest would benefit from lifestyle change to boost their levels.'

Research shows that one of the best ways to increase levels of the hormone is to lose weight.

A 2013 review of 23 studies found that weight loss was associated with significant increases in testosterone levels and that the increase was proportional to the amount of weight lost.

'If you have problems with testosterone, the first thing to look at is your waistline,' Dr Jayasena told the Daily Mail. 'The more weight you lose, within healthy ranges, the higher your testosterone goes.'

He explained that it is not just overall weight loss that is important, but where you carry it. Men with excess fat around their waist are more likely to have worse metabolic and reproductive health.

Many doctors advise keeping your waist measurement to less than half your height – a simple way to reduce the risk of type 2 diabetes, heart disease and high blood pressure.

A larger waistline is a strong indicator of higher levels of visceral fat.

While this type of fat – which is stored deep in the abdomen, around the organs – cannot be seen directly, it is considered particularly harmful. And experts have said it may also play a role in lowering testosterone.

A 2018 study of more than 300 men found those carrying higher levels of abdominal fat had testosterone levels 12 percent lower than men whose weight was more evenly distributed.

This is because visceral fat is hormonally active, helping convert testosterone into estrogen – the primary female sex hormone – which can further suppress levels and contribute to symptoms such as reduced libido, erectile difficulties and extra weight gain.

To tackle this type of fat, improving overall fitness is key. Exercises that raise the heart rate – such as running, swimming or cycling – are particularly effective at reducing visceral fat.

'There isn't strong evidence that one specific type of exercise boosts testosterone more than another,' Dr Jayasena said. 'But what makes a difference is improving your overall fitness – particularly aerobic fitness.

'It's not just about lifting weights. Regular activity that leaves you out of breath is what helps drive these changes.'

In addition to losing weight around the waist, experts say one of the most important factors in preventing declining testosterone levels is a good night's sleep.

Dr Foster said quality is just as important as quantity – with the vast majority of testosterone produced in deep-sleep stages.

When sleep is cut short or disrupted by things like shift work or young children's schedules, the hormonal signals that trigger testosterone production weaken, causing levels to fall. While napping may help you catch up on sleep, it will do nothing for your testosterone levels, Dr Foster explained.

There is no universal 'perfect' amount, but research published in the journal Andrology found that for men aged 41 to 64 a healthy goal is seven to eight hours a night – any less is linked to lower testosterone levels.

Another study, from the University of Chicago, found sleeping for just five hours a night reduced testosterone levels by 10 to 15 percent.

'Sleep is a great thing because, if you have sleep loss, you don't get that natural spike of testosterone all men should have in the morning,' Dr Jayasena said.

'People seem to think sleep is something they can skimp on, when lack of it is probably doing the most harm,' Dr Foster added.

While social media is awash with advice on supplements that claim to boost testosterone, getting the basics right matters far more.

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Focusing on macronutrients – the balance of carbohydrates, protein and fats – as well as overall calorie intake, is likely to have the biggest impact on hormone levels. That said, some nutrients may play a supporting role.

Dr Foster said there is evidence that deficiencies in key vitamins and minerals, including vitamin D and zinc, can contribute to lower testosterone. There is also early research suggesting compounds found in foods such as cacao may have an effect. One study in healthy young men found that a supplement containing cacao and pomegranate extract increased free testosterone levels by 25 percent over 56 days, compared to a placebo.

However, experts caution that such findings are preliminary and should not be overstated.

'No supplement will compensate for a poor diet or unhealthy lifestyle,' Dr Foster told the Daily Mail.

Smith agreed, and said social media often overcomplicates what is a simple equation.

'Social media preys on symptoms a lot of men in their 40s have,' he said. 'But the reality is, you can't improve your health without putting in the work.

'My testosterone levels are now at the top end of the scale. Exercising, eating well and prioritizing sleep takes discipline, but it's far more effective and comes without risks associated with TRT. It's a shame that, with more people taking it, some find it hard to believe I've done this naturally.'

Alongside losing weight and getting enough sleep, experts say managing stress is key to a healthy testosterone level.

The stress hormone cortisol is released by the adrenal glands in periods of pressure, helping the body respond to threats. But in busy modern life, that system can be switched on for long periods.

'Acute stress triggers cortisol,' Dr Foster said. 'But we live in a world of constant low-level stress – emails, long working hours – so many are exposed to persistently raised levels.'

Over time, this can disrupt the hormone system. Testosterone production is controlled by a signalling pathway between the brain and testes. When stress is prolonged, elevated cortisol interferes with this process, damping the brain's ability to send chemical signals that stimulate production of the hormone.

At the same time, the body shifts into survival mode – diverting energy away from reproduction and hormone balance.

'If your body is constantly in fight-or-flight mode, it is not prioritizing reproduction,' Dr Jayasena told the Daily Mail.

This can contribute to lower testosterone levels, particularly in men affected by poor sleep, excess weight or inactivity.