Why Is Gray Hair Hard to Color?
Melanocytes, cells in your hair follicles, stop producing melanin as we age. Melanin is what gives hair its color, so lack of melanin makes your hair turn white or gray. Experts do not know why we stop producing melanin, but it may be due to our DNA telling our bodies to stop working or the cells may simply wear out. Either way, most women want to get rid of gray hair fast.
Hair dye works by penetrating the cuticle, but the cuticle on gray hair is tightly closed and difficult to open. If hair color can't penetrate the shaft, it can't dye the hair.
Henna contains tannin, which is what dyes hair. When mixed with a slight acid, the acid dissolves the cell wall to release tannin. The dye is then released from the dye mixture and binds with keratin in the hair shaft. The longer you leave the dye solution on the hair, the darker the color will be.
How to Use Henna for Gray Hair
It's important to follow the manufacturer's directions exactly for best results. You will need to mix the powder with an acid like lemon juice or orange juice to release the natural tannin. Some henna hair dyes are combined with other herbs and flowers to make different shades of brown or red.
Heat helps release more tannin, so use a shower cap or wrap hair in plastic wrap to trap your body's natural heat. You can also use a hair dryer periodically to heat the solution.
Your hair color may be bright for the first one to two days after you dye it, but henna for dye hair will fade slightly to reveal a beautiful shade that lasts from four to six weeks.