What Happens with Dead Hair?
Dead hair, once separated from its follicle, simply ceases to grow. It no longer receives nutrients or signals from the body. The hair shaft, which is essentially a protein strand (keratin), remains largely unchanged unless subjected to external damage like heat styling or chemical treatments. It can break, split, or become damaged, but it doesn't "die" further. A dead hair follicle, however, is a different matter.
It's crucial to distinguish between the hair shaft (the part we see) and the hair follicle (the root). The hair shaft itself is dead, much like a fingernail. The living part is the follicle, located beneath the skin's surface. This follicle is responsible for hair growth.
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Dead Hair Follicle: A dead hair follicle cannot produce new hair. The lack of blood circulation prevents nutrient delivery, ultimately leading to hair loss and making regrowth impossible. A lack of blood circulation worsens and quickens the hair loss resulting in a lack of nutrition and causing the follicle to die. (Reference 1)
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Damaged Hair Shaft: Damaged hair (split ends, breakage) is different from dead hair follicles. Damaged hair can be improved or repaired by cutting off damaged sections, using conditioners, or avoiding harsh treatments. Contrary to common belief, you can often heal damaged hair without a complete haircut. (References 2, 3, 4, 6, 7, 8, 9, 10)
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Hair Growth Cycle: Hair follicles cycle through growth (anagen), resting (catagen), and shedding (telogen) phases. During the telogen phase, the hair naturally falls out, and a new hair grows from the same follicle, provided the follicle is healthy. (Reference 5)
What Happens if You Don't Cut Split Ends?
Leaving split ends untreated will not cause them to split all the way to the root. While split ends themselves are purely cosmetic, severe neglect can lead to breakage higher up the hair shaft, resulting in more significant damage and shortening hair length. (References 2, 3, 4)
Can Dead Hair Follicles Be Revived?
While a completely dead follicle cannot be revived, the potential for regrowth depends on whether the follicle is merely dormant or truly dead. Several factors can lead to hair follicle dormancy (which may be reversible), including age, genetics, and medical conditions. There are medical and cosmetic treatments available that may stimulate dormant follicles to resume growth, but not for follicles that are definitively dead. (Reference 7)
