Greying is a natural part of ageing that is genetically determined. It can't be reversed with herbal remedies or nutritional supplements. According to WebMD, research pinpoints depletion of pigment-producing cells in the follicles, and hair's natural hydrogen peroxide, as the main culprits. Researchers continue to search for solutions that prevent internal causes for greying. For now, you can cover up the grey hair on your beard with anti-grey dyes. This is the best way to stop grey hair from ageing you any more than it needs to.
Clean a small area of your skin on the inner bend of your elbow with soap and water. Mix equal dime-sized parts of the colour base and developer in the mixing tray with the opposite end of the application brush.
Apply the mixture to the clean spot with a cotton swab and let it dry. Store tightly-capped colour base and developer.
Wait 48 hours and watch for signs of redness, burning, itching or other discomfort on your patch test area. If you experience any of these symptoms, you're allergic to the dye and shouldn't use it on your face.
Put on an old T-shirt so you don't ruin good clothes if the dye drips on you. You don't want to go shirtless and get it on your body either.
Wash your beard with a cleanser or soap and warm water using a toothbrush. This removes debris, dirt and oils deep down in the beard while bristles exfoliate and remove flaky dead skin. Rinse and pat your skin dry.
Apply petroleum jelly all around your beard's hairline, on your lips, nose (if dying a moustache) and anywhere else you think the dye could get. This allows you to easily wipe any spot where dye runs or drips immediately with tissue or cotton swab, before it can stain your skin.
Put on gloves and mix equal parts colour base and developer in a tray.
Mix the base and developer with the tail-end of the applicator brush. Recap any left over product if it's safe to store for another use (according to the packaging).
Dip the brush into the mixture and immediately apply it to the dry beard. Use upward and downward strokes to cover all hairs. Do this step immediately after the mixture is prepared and apply it quickly.
Set a watch or timer for the time recommended by the manufacturer once the entire beard is covered.
Rinse the beard thoroughly with warm water immediately after time is up. When water runs clear, use shampoo on the beard to wash it clean. Pat it dry.
If you also have a moustache, dye it as well so the colour matches. Beard texture is different from scalp's hair so it may be more resistant to dye, especially the white hairs. Use a dye specially formulated for beards or moustaches. If your scalp hair is an uncommon colour, consult a stylist who can mix colours to get you a good match.
If greying is due to skin pigmentation problems such as vitiligo, do not use traditional beard dying kits, as the chemicals may cause a harmful allergic reaction. Instead, consult with a dermatologist to see if a natural, henna-based dye is a safe option. Do not use dyes on eyelashes or eyebrows. Dye products will usually stain porous surfaces. Protect countertops with paper towels.