LONDON, United Kingdom (AFP) — Social media claims by clinics promoting testosterone treatment for men to improve their physique and mood are driving large numbers to pay for unnecessary medication that can have serious side effects, doctors say.

Men’s hormone levels can fluctuate for lifestyle reasons but many are being prescribed testosterone replacement therapy (TRT) without medical need despite the health risks, doctors in the UK and Australia told Agence France-Presse.

Promotional campaigns by private clinics use social media and influencers, as well as an ad campaign in the London Underground, to encourage young body-conscious men to test their levels, claiming fatigue or irritation are symptoms.

“Do you wish you could have more energy? Less body fat? A higher sex drive?” asks one ad.

Costly treatments could be the answer.

The trend is now affecting the state-funded National Health Service (NHS), since many seek free treatment there.

The number of men referred to NHS specialists after being diagnosed privately “has really exploded,” said Channa Jayasena, a professor of endocrinology at Imperial College.

“It’s a huge problem for us, which is impacting our ability to treat other patients.”

TRT is needed by those with true deficiency, known as hypogonadism, including men who never went through puberty or had testicular cancer.

But some clinics prescribe it to men with normal levels and risking side-effects including infertility and thickened blood that carries cardiovascular risks, doctors warn.

While private clinics are not obliged to disclose numbers, Jayasena estimated “hundreds of thousands” of men in the UK have accessed costly TRT privately.

And most “just don’t need it at all,” he said.