Shiny, healthy hair starts with the vitality of cells in the hair follicle, where hair is manufactured, says Katz.

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Common problems include overactive oil glands, bacteria growth within follicles and pores and problems with the keratinization process, where cells are normally sloughed off the skin, pushed out of the hair follicle and replaced by new cells.

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Although it is understandably tight-lipped about the exact mechanism behind its success, one probably enlists the help of cells called keratinocytes, which interact naturally with the dermal papilla cells of the hair follicle and secrete a chemical factor that supports their growth.

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