Nappy, or kinky textured hair, grows an average rate of one-quarter to one-half inch per month, the same as any other texture. Taking vitamin supplements claiming to affect hair growth may work to speed up growth, but proper care is required to retain growth gains.
Highly textured hair is a fragile hair type, and requires gentle handling so that it doesn't break easily. This includes cleansing with gentle shampoos, preferably ones that don't contain sulfates. Frequent conditioning and deep conditioning with moisturizing products help to hold onto much-needed moisture. Avoid direct heat as much as possible in the form of blow-drying and thermal styling. When coloring this hair texture, do not use bleaching processes as they will dry out the hair. Removing split ends on a regular basis, using wide-tooth combs for detangling and gentle hair care all help to maintain length.
Taking supplements to make hair grow faster isn't a proven science. Biotin is a popular supplement, but should be used with care. While some people report faster hair growth from taking vitamins, others report no noticeable increase or report negative side effects like increased acne. It's important to drink adequate amounts of water when taking a supplement like biotin to avoid skin problems.