I assure you, its normal to colour in hair. Its very natural also to lose pigments in the hair as you age or even as young and being in your 20s.
On the human body are millions of tiny sacs which line the skin and they are called hair follicles. These follicles grow hair and also generate the colour for the hair. As we age, these sacs begin to wither and cause a lack of the pigment.
The causes resulting to loss of pigment in the hair could be from the following :
Deficiency in vitamins b6, b12, D or E, biotin contribute to premature graying. Various report in the past few years have indicated that deficiency in vitamin D3, b12 and copper sufficient foods have also caused lose of hair pigment but also shown that when these vitamins are replenished, the colouring is regained.
Genetics: Well I'm sure you guessed this one. Genetics plays a very vital role in the colouring of ones hair. Likewise race and ethnicity.
Finally, while genetics play a major role in hair pigmentation, oxidative stress takes the hat for this one. This form of stress causes an imbalance when antioxidants are not enough to counter the damaging effects of free radicals which causes the graying, aging and diseases.
There are several causes of loss of hair pigment at an early age that will make baldness occur.
For this case we can treat two hypotheses:
Some studies seem to prove a link between stress and the appearance of white hair. Just look at photos of US President Barack Obama in 2009 and 2016 to see how his life in the White House has changed his physique.
There is nothing worse than tobacco for the health and appearance of the skin and hair. Studies have shown a link between smoking and the appearance of white hair before the age of 30. The skin of smokers is wrinkled, and their hair is also, in a way, because tobacco affects the hair follicles.
In some rare cases, the early appearance of white hair may indicate a health problem such as an autoimmune disease that affects the skin and hair (vitiligo or alopecia), a thyroid disorder or pituitary glands, or , a lack of vitamin B12 caused by anemia.