Nootkatone

Nootkatone was identified as a naturally occurring AMPK activator in a 2010 study showing that it increased AMPK activity in muscle cells and mouse tissues, raised whole-body energy expenditure, and, with long-term intake, reduced high-fat, high-sucrose diet induced weight gain, abdominal fat and metabolic disturbances in mice; it also extended swimming endurance ^[1]. These findings frame it as a candidate for metabolic support and mild performance enhancement.

Separately, nootkatone has a well-established role in public health entomology. It repels and can kill ticks, mosquitoes and other arthropods, and the US Centers for Disease Control and Prevention supported its development as a safer, plant-derived repellent; it has been evaluated as an acaricide and repellent against Ixodes ticks and other vectors ^[2]. Its dual identity as a metabolic ingredient and an insect repellent is unusual.

As a supplement, nootkatone is far less studied in humans than its mechanistic and animal profile suggests. It is generally recognised as safe as a flavouring, but data on oral supplementation for metabolic or cognitive benefit in people are limited, and any wakefulness or focus effects are described anecdotally rather than demonstrated in trials.

Nootkatone is used as a food flavouring and fragrance and is generally regarded as safe in those contexts; the EPA has concluded it poses low risk to human health as a registered biopesticide. As an oral supplement at higher doses, human safety data are limited, and its metabolic (AMPK-activating) effects have not been characterised for long-term use in people. It may interact in theory with other AMPK-affecting agents or antidiabetic drugs. As with any grapefruit-derived compound, users on medications sensitive to citrus constituents should be cautious and consult a clinician.

Nootkatone was first isolated from grapefruit and Alaska yellow cedar (nootka cypress, the source of its name) and became valued in the flavour and fragrance industry. Its biological profile broadened in 2010 when Japanese researchers at Kao Corporation reported its AMPK-activating, anti-obesity properties, and in parallel public-health scientists and the CDC advanced it as a plant-based insect repellent and acaricide, culminating in EPA registration.

Nootkatone is best known to the public as a grapefruit aroma compound and to entomologists as a promising natural repellent. In the supplement space it has a modest, curiosity-driven following for AMPK-based metabolic and endurance support. Experts view the metabolic mechanism as legitimate but caution that human supplementation evidence is thin and that most positive data come from rodent studies.