Do Testosterone Boosters Work? What the research Says (UK)

What do testosterone boosters claim?

"T boosters" are food supplements sold on the promise of more energy, muscle, libido and drive. They are usually blends of herbs (tongkat ali, fenugreek, ashwagandha, tribulus, maca), minerals (zinc, magnesium), vitamins (D, B6) and amino acids such as D-aspartic acid. The pitch is simple: take a capsule, raise your testosterone, feel younger.

It is a fair question to ask. Testosterone does fall with age, and the symptoms people blame on it (tiredness, low sex drive, belly fat, low mood) are real and common. But the NHS points out that the fall is slow, about 1% a year from around 30 to 40, and that many of these symptoms have nothing to do with hormones.

What does the evidence show?

The best single look at the market is a 2020 study of 50 T booster products in the World Journal of Men's Health. Ninety percent claimed to boost testosterone, but only 24.8% of those claims had any published data behind them. About 1 in 10 products contained ingredients with data suggesting they could lower testosterone, and many packed vitamins and minerals well above recommended amounts, sometimes over the safe upper limit.

A 2024 systematic review pooled 52 trials of 27 ingredients. Its conclusion: most fail to raise total testosterone. Here is how the main ingredients stack up.

Tongkat ali

This is the ingredient with the most consistent signal. A 2022 meta-analysis found it raised total testosterone, with the clearest effect in men diagnosed with low levels (hypogonadism). The trials are small, extracts differ, and some are funded by extract makers. The authors say more research is needed before it is used in practice.

Ashwagandha

A 2026 meta-analysis found ashwagandha lowered cortisol (a stress hormone) and raised testosterone in men, but with a lot of variation between trials. The bigger issue in the UK is safety. The Food Standards Agency has flagged reports linking ashwagandha with thyroid effects, low blood sugar and possible liver injury, says there is no established safe level for supplements, and has asked its Committee on Toxicity (COT) for a risk assessment. As of mid-2026 that review was still under way, and the FSA advises pregnant women and people with liver conditions to avoid it (Which?).

Fenugreek, D-aspartic acid and vitamin D

Fenugreek may have a small effect, but a 2026 review called the evidence very uncertain and said it does not support boosting claims. D-aspartic acid results are all over the place. Vitamin D is worth taking in UK autumn and winter for bone and muscle health, but a 2026 meta-analysis found no clear effect on testosterone.

Zinc

Zinc is needed to make testosterone, so a real deficiency can lower it. But most UK men get enough from food (about 9.5mg a day, per the NHS), and extra zinc does not push levels higher. The NHS advises not taking more than 25mg of zinc supplements a day unless a doctor says so. Some boosters contain more.

What actually affects testosterone?

The things with the strongest evidence are not in a capsule:

• Sleep. In a JAMA study, young men limited to 5 hours a night for a week had noticeably lower daytime testosterone.
• Weight. Carrying extra weight, especially around the middle, is linked to lower testosterone, and the NHS notes late-onset hypogonadism is more common in men with obesity or type 2 diabetes. Losing weight tends to bring levels back up.
• Alcohol. Heavy drinking is linked to lower testosterone and is on the NHS list of lifestyle factors behind "male menopause" symptoms.
• Strength training and activity. Regular exercise supports healthy weight, sleep and mood, all of which feed into hormone levels.
• Stress, smoking and diet also appear on the NHS list.

How is low testosterone actually diagnosed?

Not from symptoms alone and not from one reading. The British Society for Sexual Medicine (BSSM) guidelines say testosterone should be measured in the morning, when levels peak, and confirmed with a repeat test before any diagnosis. A GP will usually also look at SHBG (a carrier protein), LH and FSH (signals from the brain) and other causes of your symptoms.

Testosterone replacement therapy (TRT) is a prescription-only medicine in the UK. It can help men with confirmed deficiency, but it also affects fertility (it can switch off sperm production), red blood cell levels and other things that need monitoring.

Who should be careful?

• Anyone trying for a baby. Some boosters and, especially, TRT can lower sperm production.
• People on medication. Ashwagandha may interact with thyroid, diabetes, blood pressure and sedative medicines. Ask a pharmacist.
• People with thyroid or liver conditions, or who are pregnant should avoid ashwagandha, per the FSA.
• Athletes in tested sport: blends carry a risk of contamination. Look for Informed Sport certification if you take anything.
• Online TRT clinics. Some private services prescribe testosterone after a single home test or loose thresholds. Ask whether they follow BSSM guidance (two morning tests, checks for other causes, fertility discussion and monitoring), and tell your GP.

If you want to try one: what to look for

We have not listed any booster products, because none has strong enough evidence for us to recommend. If you choose to try one anyway:

• Pick a single ingredient with some evidence (tongkat ali) rather than a blend of ten.
• Check the dose of zinc, vitamin B6 and vitamin D against NHS limits.
• Prefer third-party tested brands (Informed Sport or Informed Choice).
• Give it a fixed trial (8 to 12 weeks) and judge it on how you feel, not marketing claims.
• Avoid ashwagandha if you are in any of the groups above.

Bottom line

T boosters are mostly marketing. A couple of ingredients show small effects in men who already have low levels, but the 2020 product review found most claims unsupported and some products contained ingredients that could do the opposite. If you have symptoms, start with sleep, weight, alcohol and strength training, and see your GP for two morning blood tests before spending money on supplements or private TRT.