Testosterone shots can not only overcome low libido in men but also protect them against heart attacks, says a US study. A five-shot course of the hormone boosted male sex drive as well as their fitness levels, mood and their ability to concentrate. They also reported weight loss. The incidence of low libido dropped from 64% to 10% after treatment.

The study was conducted on men with medically deficient levels of testosterone, known as hypogonadism.

Experts believe the findings could be relevant to the far larger group of ageing men whose testosterone has simply dropped to low levels.

The hormone is responsible for the development of male sexual characteristics as well as maintaining muscle bulk, keeping bones healthy, helping the body to produce enough red blood cells and improving mood.