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Andrew Huberman, Ph.D.@hubermanlabTikTok

Tools to set your cortisol rhythm

original sound — @hubermanlab

what it claims

To optimize your energy during the day and your sleep at night, you must regulate your cortisol curve by stimulating its natural morning peak (via bright light, hydration, exercise, and potentially licorice root or grapefruit) while avoiding elevating cortisol at the end of the day.

holds up

The Cortisol Awakening Response (CAR) is a well-documented biological mechanism. A randomized clinical study (Petrowski et al., 2019) confirms that morning exposure to bright…

noli's read

The Cortisol Awakening Response (CAR) is a well-documented biological mechanism. A randomized clinical study (Petrowski et al., 2019) confirms that morning exposure to bright light significantly stimulates this peak compared to dim light. Regarding cold, a clinical trial on repeated immersion shows that the rise in cortisol fades by the fourth week due to habituation. For caffeine, a randomized controlled trial (Lovallo et al., 2005) reveals a partial tolerance: daily consumers see their morning hormonal response attenuate, although it does not disappear completely. Finally, the impact of licorice root and grapefruit is supported by a crossover clinical trial (Methlie et al., 2011) showing that they inhibit the cortisol-degrading enzyme, which prolongs its effect.

the sources

Claimed by Andrew Huberman, Ph.D. Noli grades the claim, never the person.

Decoded by Noli · July 13, 2026 · the original post

What the graded evidence says

Evidence: A-

Effect: circadian phase / melatonin timing — morning light advances; evening light delays
Measured on: reviews + expert consensus

Core circadian physiology is very well established; specific lux targets less so.

Andrew Huberman, Ph.D. in the Register144 claims graded · solidity 82/100See their record →

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Others on this

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Noli has read similar claims

Other advice in the Register that leans on the same research.

To dispel the feeling of being exhausted but overstimulated at bedtime, adopt a regular and relaxing sleep routine (low light, calm sounds, no screens) coupled with a progressive light alarm.

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