Use licorice root in the morning as a potent cortisol elevator (with caution — possible drug interactions), and grapefruit to extend how long cortisol stays active in the body; train early to match cortisol's circadian rhythm, or add cortisol-lowering steps after a late workout to avoid what's called "type 2 burnout."

noli's read

Both pharmacological mechanisms are real and well documented: licorice's glycyrrhizin inhibits the 11-beta-HSD enzyme that normally inactivates cortisol, prolonging its action (endocrinology studies since the 1980s-90s, confirmed in healthy-volunteer trials); grapefruit works through a different mechanism — it inhibits the liver enzyme CYP3A4 that breaks cortisol down, increasing its availability, an effect used clinically in adrenal-insufficiency cases specifically to extend the effect of replacement cortisol. The warning about drug interactions with licorice is appropriate and consistent with the literature (documented hypertension and low potassium with chronic use). "Type 2 burnout," however, is a term Huberman has popularized on his podcast rather than a recognized entity in the endocrine literature; the underlying advice — offsetting a late workout with calming steps so next-day cortisol isn't disrupted — is plausible but isn't named or measured this way elsewhere. Verdict: mixed — the licorice and grapefruit pharmacology is solid, but it's a targeted, cautious use case rather than advice for "everyone," and "type 2 burnout" outruns what the research formally recognizes.

the sources

1. 1Buijze GA et al. 2016
2. 2Sramek P, Simeckova M, Jansky L, et al. 2000
3. 3Kelly JS, Bird E. 2021