If you have ever questioned whether stress might be behind those extra, possibly early, grey hairs, you are not alone. On his show Dr Xand's Con or Cure, the well-known medical expert addressed the topic during a conversation with co-host and journalist Ashley John-Baptiste.

Best recognised from BBC Morning Live, Dr Xand explained: “Stress does play a role — so here’s what happens when your hair starts turning grey.”

"The cells, the melanocyte - the cells that make the pigment melanin in the hair follicles - stops working, and so the hair with no pigment is white or gray. Basically that’s the default colour. And stress can definitely contribute to those pigment producing cells working less well in several different ways. The stress hormones do it, the general inflammation of stress in the body contributes to it. And so although most of your tendencies to go grey is genetic, it definitely is sped up by stress. It’s not a myth."

Backing up his claims, one study which was funded in part by National Institute of Health’s National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) and other NIH components, was later published in Nature.

It reads: "The research team, led by Dr. Ya-Chieh Hsu of Harvard University, used mice to examine stress and hair graying. The mice were exposed to three types of stress involving mild, short-term pain, psychological stress, and restricted movement. All caused noticeable loss of melanocyte stem cells and hair graying.

"Having established a link between stress and graying, the scientists then explored several potential causes. They first tested whether immune attack might be responsible for depleting melanocyte stem cells. But stressing mice with compromised immune systems still led to hair graying. The team then investigated the role of the stress hormone corticosterone, but altering its levels didn’t affect stress-related graying.

"The researchers eventually turned to the neurotransmitter noradrenaline, which, along with corticosterone, was elevated in the stressed mice. They found that noradrenaline, also known as norepinephrine, was key to stress-induced hair graying. By injecting noradrenaline under the skin of unstressed mice, the researchers were able to cause melanocyte stem cell loss and hair graying."