Hair

The science behind hair growth and loss involves a complex interplay of biological factors, as discussed by Andrew Huberman on the Huberman Lab.

1. Hair Growth Phases: Hair growth occurs in cycles: the anagen (growth), catagen (recession), and telogen (rest) phases. The duration of these phases varies by individual and body region. Critical factors like blood supply, stem cells, and hormones influence these cycles 1.

2. Hormonal Influence: Hormones, especially testosterone and its derivative dihydrotestosterone (DHT), play significant roles in hair dynamics. DHT promotes beard growth while contributing to baldness by affecting androgen receptors in the scalp. Treatments for hair loss often target the conversion of testosterone to DHT or DHT activity itself 2.

3. Chemical Factors: Insulin-like Growth Factor 1 (IGF-1) and Cyclic AMP (cAMP) are known to extend the growth phase of hair, while elements like phosphodiesterase and TGF-beta 2 act as growth inhibitors. Hormones and genetic factors significantly influence the expression and density of these chemicals, impacting hair health and loss patterns 3.

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     1

     Hair Growth Phases

     00:31:12
     
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     2

     Hormones and Hair

     01:02:33
     
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     3

     Hair Growth Dynamics

     01:06:26
     
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     4

     Hair Science Unveiled

     00:00:00
     

For more detailed insights, the episode "The Science of Healthy Hair, Hair Loss and How to Regrow Hair" delves deeper into these topics 4.