Thanks for writing to us.
I will answer your queries specifically.
1)Causes of premature greying-It is mostly genetic or familial. other causes are nutrtional deficiency, stress
disroders, anemias, any chronic illness
2) The treatment suggested by your friend is satisfactory. Hairbless contains all the vital nutrients required for hair growth. Altris gel is melitane based gel and is found to prevent premature graying and also turns the grey hair black. However these medicines usually work better in people who are adoloscent. But still you need to use these medicines as it would offer you some benefit.It wont turn your grey hair black but may prevent further graying of hair. However do not expect immediate response, the treatment needs to be continued for long.
3) duration - long. Need to continue for may be an year or more.
4) take diet rich in proteins
, vitamins and minerals
.Stress on milk,curd, broccolli, carrots, cabbage,nuts( sunflower seeds, almonds, walnuts), fruits, leafy vegetables
Avoid stress, avoid smoking, exercise regularly.
Hope this answered your query.