There’s a home remedy for grey hair where dried ridge gourd is boiled in coconut oil and then you massage it in hair , scalp. I have not tried it. Coconut oil and ridge gourd both are cooling . So am thinking if hair prematurely turned gray due to heat then this might help.
If you are trying it out , why not eat also ? That will help from inside . So I cooked ridge gourd in coconut oil. Added some frozen Lima beans into it .