Bad news for male gym bunnies - weight-lifting is now thought to play a key role in a man's receding mane, especially if the workouts are followed up by protein powder drinks.
Frequent weight training is thought to increase the body's testosterone and Dihydrotestosterone (DHT) levels, which are considered key causes of baldness.
Although these hormones are naturally occurring, DHT - a converted version of testosterone - attaches itself to a man's hair strand's receptor cells, blocking the absorption of essential nutrients.
Over time, this causes the hair follicle to shrink and eventually die.
So, if you buy into the theory, gym-goers are raising their exposure to DHI, and risking early hair loss.
But where does the protein shake part come in ?
Dr Thomy Kouremada-Zioga told the Daily Express: "Protein shakes will very often contain growth hormones such as Creatine and DHEA, which not only increase muscle mass, but also increase testosterone levels in the bloodstream"
Higher testosterone means more DHT, says Dr Kouremada-Zioga. "Sadly, this is something that most men are unaware of, until they notice that their hair loss has already become more apparent."
But the experts say the risks can be minimalised if people do cardio exercise instead of weights, and skip the protein shakes in favour of natural sources of protein such as chicken, fish and eggs.
Dr Kouremada-Zioga said the problem was generally limited to those who already had a predisposition to male pattern baldness.
"It is important to distinguish between cause and effect here. Protein shakes do not cause hair loss," he said.
"They do, however, accelerate hair loss for those men who suffer with androgenetic hair loss or alternatively, those who are predisposed to balding, as many men are."
And when it comes to thinning hair and bald patches, there are few treatments available.
Clinical trials have proven that the chemicals Minoxidil and Finasteride can help, with the former being the key ingredient in 90 per cent of hair loss treatments.
Minoxidil, originally created as a blood thinning agent, can be effective at halting hair loss if used early, but it doesn't promote new hair growth.
Other treatments include Finasteride tablets, or hair transplants.