DHEA (dehydroepiandrosterone) is an endogenous hormone produced primarily by the adrenal glands. Its use to "support" adrenal gland function is based on its role as a precursor to sex hormones (estrogens and androgens) and its natural decline with age or in certain disease states. Scientific interest in DHEA supplementation for adrenal support is most evident in the context of adrenal insufficiency, such as Addison’s disease, where DHEA levels are often low. Some clinical trials have shown that DHEA supplementation in individuals with adrenal insufficiency can improve well-being, mood, and sexual function, though the effects are generally modest and not universally observed. There is little evidence that DHEA can "boost" adrenal gland function in healthy individuals or that it meaningfully reverses fatigue or other symptoms attributed to "adrenal fatigue," a concept not widely accepted in mainstream medicine. Systematic reviews and guidelines typically suggest that DHEA supplementation may be considered as adjunct therapy in specific cases of diagnosed adrenal insufficiency, especially to address quality-of-life issues, but they also note inconsistent results and potential side effects. Therefore, while there is some scientific basis for the use of DHEA in certain settings related to adrenal dysfunction, the overall quality and consistency of evidence is limited, hence the moderate evidence rating.