There is preliminary evidence that some (but not all) of these herbs may help to reduce symptoms of stress or anxiety. Herbal adrenal support formulas often contain a combination of herbs such as ashwagandha, ginseng, holy basil, rhodiola, and schisandra. However, while stress and fatigue can have very real effects on physical and emotional health, there is not enough evidence to prove that these effects are caused by improperly functioning adrenal glands ( Cadegiani, BMC Endocr Disord 2016 Endocrine Society 2018). 'Adrenal fatigue' is the concept that in people who experience chronic emotional or physical stress, the adrenal glands can become overburdened and stop working efficiently-leading to symptoms such as difficulty waking in the morning, tiredness during the day, and salt and sugar cravings. The adrenal glands secrete the 'fight or flight' hormones adrenaline, cortisol (to increase blood sugar) and aldosterone (to increase blood pressure). Additionally, an analysis of popular adrenal support supplements on the market found that all contained small amounts of thyroid and steroid hormones, which could potentially cause adverse effects or interfere with blood test results.

While some of these ingredients have individually been shown to reduce fatigue or symptoms of stress, there is currently little evidence that 'adrenal support formulas' do the same or improve adrenal gland function. Supplements promoted to increase energy, reduce stress and other symptoms caused by 'adrenal fatigue' may contain a variety of ingredients, including vitamins and minerals, herbs, and/or dehydrated adrenal gland tissue from animals (typically from bovine source, i.e., cows).

Side effects of adrenal cortex