Hormesis

What It Is

A biological principle describing a beneficial adaptive response to low doses of a stressor that would be harmful at higher doses — "what doesn't kill you makes you stronger." The foundational principle behind exercise (muscle damage → repair and growth), intermittent fasting (metabolic stress → metabolic adaptation), heat shock proteins (heat/cold exposure → cellular protection), and the benefits of plant polyphenols (plant stress compounds → human antioxidant enzyme activation via NRF2). Almost every major longevity intervention works at least partly through hormetic mechanisms.

Key Context

In skincare: chemical exfoliation, retinoid use, and professional peels work via controlled hormesis — causing controlled cellular stress that triggers collagen stimulation and repair responses. The key is dose: too little does nothing, optimal creates the adaptive response, too much causes damage.

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