Unfortunately as humans we will inevitably get greyer hair as we begin to age. There is very little we can do about it, but there are a few ways to slow the spread of it. Most humans begin to get greyer hair around the age of 40 but there are many factors that can change the rate at which it greys.
Genetics and heredity also play a big role in the rate at which hair turns grey. Some children are born with whitish or grey hair. Nothing can be done about inherited traits other than dying the hair. The two genes that appear to be responsible for the graying process are Bxl2 and Bcl-w.
Human hair begins to grey for a few reasons. The body stop producing melanin and the hair begins to lose its color. Melanin is the colored pigment that appears in skin and hair. This happens when the stem cells at the base of each hair follicle begins to die. These stem cells product melanocytes. Melanocytes are the cells that produce melanin.
There are a few factors that can effect this process. The first is smoking. Several studies have shown that tobacco smokers are often significantly more likely to prematurely grow grey hair. This is often cited as a major reason to quite smoking. On top of this smoking has many other detrimental effects on the health of an individual. Chemo-therapy can also have effects on hair color. It has been shown that people with grey hair who receive chemo therapy may begin to grow darker hair.