Energy Supplements Compared: Ginseng, Rhodiola, Cordyceps, B Vitamins and "Adrenal Support"

How to read this comparison

Products sold for "energy" are mostly dietary supplements. In the US they are not approved by the FDA before sale. [1] Evidence labels: established recommendation, promising but limited, mixed, insufficient evidence, preclinical (animal or lab only). Where we looked and found nothing usable we say Proper evidence not found. None of this is dosing advice. Studies below used the amounts their authors chose. Talk to a clinician first, especially if you take medicines. See How interactions work and Product quality and contamination.

At a glance

Asian ginseng (Panax ginseng)

Evidence: mixed. NCCIH says Asian ginseng alone may have a small beneficial effect on general (non-disease) fatigue, that certain herbal formulas containing other ingredients may help chronic fatigue but not ginseng alone, and that not all research agrees. [1] A 2023 meta-analysis of 19 randomized trials found no significant reduction in fatigue overall (SMD -0.36, 95% CI -0.82 to 0.11), but significant reductions for ginseng herbal formulas and for general fatigue, with small effect sizes. [3] Short-term oral use of up to 6 months appears safe for most people, insomnia is the most common side effect, and rare reports include severe rash, liver damage and severe allergic reactions. It may worsen autoimmune disorders, interfere with blood clotting, lower blood sugar and interact with medicines. Some experts advise against it in pregnancy and breastfeeding. [1] See Adaptogens and Adaptogen safety.

Rhodiola

Evidence: insufficient. NCCIH says there is not enough reliable evidence to determine whether rhodiola is useful for any health-related purpose, and most research is of low-to-moderate quality. [4] A 2012 systematic review of 11 trials found contradictory results: two of six physical-fatigue trials and three of five mental-fatigue trials reported benefit, and all had high risk of bias or reporting flaws. [5] A 2011 review found possible benefit but a lack of independent replication. [6] Possibly safe for up to 12 weeks; side effects include dizziness, headache, insomnia, and dry mouth or excess saliva. An interaction with losartan has been reported. [4]

Cordyceps

Evidence: insufficient. We found small trials, not a systematic review of cordyceps for fatigue. In a 12-week double-blind trial of 20 healthy adults aged 50 to 75, a Cordyceps sinensis product (Cs-4) raised metabolic and ventilatory thresholds compared with placebo, with no change in VO2 max. [7] In a trial of 28 people, a mushroom blend containing Cordyceps militaris showed no significant VO2 max change at 1 week, and VO2 max rose after 3 weeks in the 10 volunteers who continued; it was a blend, not cordyceps alone. [8] Proper evidence not found for cordyceps relieving everyday tiredness. See Mushroom supplements and Mushroom safety.

Ashwagandha

Evidence: insufficient for energy. NCCIH says some preparations may help insomnia and stress, but there is not enough evidence for athletic performance and other uses. It may be safe up to 3 months; some people get drowsiness or stomach upset, and rare cases of liver injury have been linked to it. It should be avoided during pregnancy and breastfeeding. [9] See Cortisol and adrenal fatigue and Liver safety and supplements.

B vitamins and iron

Correcting a true deficiency can improve symptoms. [10] [11] In people without overt deficiency, a review of 16 B12 trials could not assess fatigue because only one trial reported it. [12] A small 28-day trial of 32 healthy adults reported longer running time to exhaustion with a B complex, but it is a single small study. [13] For ME/CFS, NHS says evidence is insufficient to recommend vitamin B12, vitamin C, magnesium or coenzyme Q10. [14] See Vitamin B12 deficiency and Anemia and iron deficiency.

Creatine

The International Society of Sports Nutrition position stand describes creatine as one of the most popular nutritional aids for athletes, linked to improvements in high-intensity exercise performance, and reports that supplementation in studies (up to 30 g a day for 5 years, study amounts) was safe and well tolerated in healthy people. Evidence: established for sport performance; this does not show it helps general tiredness. [15]

Pre-workout blends and stimulant stacking

Multi-ingredient pre-workout supplements usually combine caffeine, creatine, beta-alanine, amino acids and other ingredients. A review found they may improve muscular endurance and mood in the short term, but proprietary blends often hide amounts, safety studies were mostly under eight weeks, and some formulations may contain banned substances intentionally or as contaminants. Evidence: mixed. [16] Adding caffeine from several sources raises your total, and caffeine in bars, gum, supplements and medicines counts. [17] Too much causes palpitations, anxiety, insomnia and more. [17] See Caffeine and energy drinks.

"Adrenal support" and adrenal fatigue

Not supported. A 2016 systematic review of 58 studies found conflicting results and concluded there is no substantiation that "adrenal fatigue" is an actual medical condition. [18] Real adrenal disease, such as Addison disease (adrenal glands that do not produce enough hormones), is a separate medical condition. [19] One 2026 case report describes a man with rapid weight gain, fatigue and signs of Cushing's syndrome who had taken a supplement the FDA had recalled for undeclared dexamethasone; his symptoms began a few weeks after he stopped it. It is a single case, but it shows why undeclared ingredients matter. [20] For the full topic, read Cortisol, adrenal fatigue and what the science supports and Adrenal fatigue and adrenal support claims.

When to get help

NCCIH lists severe rash, liver damage and severe allergic reactions as reported with ginseng. [1] If you have severe symptoms, seek care and use your local emergency number. Tell your clinician about every supplement you use. [1] Persistent tiredness needs assessment, not a supplement: Fatigue: when to get help.