hi, welcome to HCM, The speed of hair growth varies based upon genetics, gender, age, hormones. It may be reduced by nutrient deficiency (i.e., anorexia, anemia, zinc deficiency) and hormonal fluctuations (i.e., menopause, polycystic ovaries, thyroid disease). Essential omega-3 fatty acids, protein, vitamin B12, and iron, prevent a dry scalp and dull hair color. vitamins A and C, which help with production of sebum and provide a natural hair conditioner. Protein promote hair growth. Biotin functions to activate certain enzymes that aid in metabolism of carbon dioxide as well as protein, fats, and carbohydrates. A deficiency in biotin intake can cause brittle hair and can lead to hair loss. Vitamin B5 (pantothenic acid) gives hair flexibility, strength and shine and helps prevent hair loss and greying. hope this will help you. thanks.