This Juice Cured Gray or White Hair as it is called Powerful Grey Hair Natural Remedy

Onion Juice Mixed With Lemon Juice.
How to prepare:
Peel the onions and chop them into small pieces.
Squeeze the juice out. To extract the juice, you can use a food processor, a blender, a grater or a juicer.
Massage the juice into your scalp or cover the bald patches.
Leave on for at least 15 minutes (longer if you can tolerate the smell) and then wash out using a mild shampoo.

It sounds weird but it is a Powerful Grey Hair Natural Remedy: Onion juice is rich in the enzyme catalase and has been used for centuries as a topical treatment and home remedy for grey hair. In fact, herbalists have been advising their patients to rub onions on their scalps to cure grey hair long before any hair dyes were ever invented!
Increase Vitamin Intake.

Hair follicles are not able to produce the normal amount of melanin because your body lacks Vitamin B12. You need to increase your intake of vitamin A and B in your diet so that your hair can produce more melanin. Food rich in vitamin A and B are green leafy vegetables and fruits. Banana, cauliflower, tomato, yogurt and cereals are sources of vitamin B. You can also get your adequate supply of vitamin B12 in dairy products, eggs and meat.

Use Henna on Your Hair.

Instead of using your usual hair conditioners, try applying Henna on your hair. It is applied on the hair an hour before taking a bath. It is proven to reverse the whitening color and strengthens your hair strands.

Eat Iodine Rich Food.

Iodine can prevent your hair from turning grey or white. Seafood is rich in iodine but it can also be found in carrots and bananas. Instead of using ordinary table salt, you can replace it with iodine salt to increase your iodine intake.

Avoid Stress and Unhealthy Lifestyle.

If you are constantly stressed out from work and you have an unhealthy lifestyle, then you have a higher risk of having premature white hair. Give up your unhealthy habits like drinking and smoking. Avoid being stressed out by learning to relax and release your tension through meditation.