How long does it take to repair dead hair?

Generally speaking, "dead hair" may refer to problems such as split ends, breakage, and roughness caused by physical or chemical damage. The hair shaft consists of keratinized dead cells and has no regenerative or self-repairing capability. Damaged hair shafts cannot be revived through hair care treatments but must be removed by trimming, allowing healthy new hair to grow and replace the damaged sections. Detailed analysis is as follows:

New hair grows from the hair follicles. If the follicles are healthy, hair typically grows about 1 centimeter per month. For mild damage, such as split ends, trimming combined with moisturizing treatments can lead to improved hair quality within 1-2 months. For severe damage, such as widespread hair breakage or significant damage to the cuticle, continuous trimming of the damaged sections and protection of the hair follicles are required. Usually, healthy hair strands can gradually regrow within 3-6 months. If the follicles have been damaged over a long period—for example, due to chemical exposure, malnutrition, or other factors—the hair growth may be affected. Recovery may take longer, and in some cases, treatment might be necessary to improve follicular function.

Damaged hair strands cannot be repaired. It is important to reduce hair-damaging practices such as perming, dyeing, and using high-heat blow-drying in daily routines. Maintaining a balanced diet also helps promote the growth of healthy hair and maintain good hair quality.