Hair health depends on the scalp environment, strand structure, and routine. Scalp care promotes balanced oil production and reduces irritation; cleanse with gentle surfactants and avoid harsh scrubbing. Porosity describes how easily hair absorbs and retains moisture. Low‑porosity hair resists water and benefits from lighter products and occasional heat to open the cuticle. High‑porosity hair absorbs quickly but loses moisture fast and needs richer conditioners, leave‑ins, and protective styling. Protein‑moisture balance matters: too much protein can make hair brittle, while insufficient protein reduces strength. Choose ingredients strategically—humectants like glycerin draw moisture, emollients like oils soften, and occlusives seal hydration. Limit heat damage by using protectants and moderate temperatures. Trim regularly to manage split ends. When concerning symptoms appear—sudden shedding, patchy loss, scaly plaques, or persistent itch—seek evaluation to rule out conditions like telogen effluvium, alopecia areata, psoriasis, or seborrheic dermatitis. With consistent routines matched to hair type, most people see improved texture, shine, and manageability over time.