Greying of hair is caused when cells at the hair base (melanocytes) stop producing the pigment which is responsible for giving our hair its colour, and sometimes because of kapha aggravation. Also, to continue making the colour-producing pigment, the cells need Vitamin B12. In some cases, premature greying occurs if there’s a deficiency of Vitamin B12. A diet deficient in vitamins and minerals can lead to early greying. You must take care of your diet first, stop junk food completely, along with sugary beverages, colas, soda, excess tea/coffee. Instead include Antioxidant-rich foods : Fresh fruits and vegetables, amla, green tea, olive oil, fish, flaxseeds etc. For Vitamin B12- include seafood, eggs, and meats are good sources of it, and milk, salmon, and cheese are excellent sources of vitamin D. Massage your hair with coconut/ olive oil with curry leaves added to it, or you can simply use neelibringadi thailam. Reduce tea/coffee/smoking and alcohol. Practise pranayama daily.