The Uncomfortable Truth About Energy Supplements
Most supplements marketed for "energy" do not work in healthy, non-deficient people. This is the honest starting point, and most supplement sites will not tell you this because it is bad for affiliate revenue.
True fatigue has a cause. That cause might be poor sleep, nutrient deficiency, chronic stress, a medical condition, or simply insufficient calories. Supplements can only help if the cause is something a supplement can address (typically a nutrient deficiency or a specific metabolic shortfall). No pill will overcome chronic sleep deprivation or an overpacked schedule.
With that caveat firmly in place, here are the supplements with actual evidence for improving energy, organized by how likely they are to help you.
Fix Deficiencies First: The Highest-Impact Supplements
These supplements can dramatically improve energy, but only if you are deficient. If your levels are normal, supplementation will not give you extra energy. This is not a marketing message. It is basic biology.
Iron
Who it helps: People with iron deficiency or iron-deficiency anemia
Evidence level: Very strong (for deficient individuals)
Iron deficiency is the most common nutrient deficiency worldwide and one of the most common causes of fatigue. It affects up to 10% of women of reproductive age in the United States and is more prevalent in vegetarians, vegans, frequent blood donors, and endurance athletes.
A 2012 systematic review in the CMAJ found that iron supplementation significantly improved fatigue in iron-deficient non-anemic women. The effect was large and consistent. For people who are truly iron-deficient, correction of the deficiency can be transformative.
But here is the critical point: do not supplement iron without a blood test confirming deficiency. Excess iron is toxic. It accumulates in organs and can cause liver damage, heart problems, and other serious issues. Iron is one of the few supplements where more is definitively worse if you don't need it. Get a serum ferritin test before supplementing.
If you are deficient, iron bisglycinate is the recommended form because it is well-absorbed and causes significantly less GI distress than ferrous sulfate (the old-school form). See our iron bisglycinate scorecard for product comparisons.
Effective dose: 18-65 mg/day of elemental iron for deficiency, depending on severity. Take with vitamin C to enhance absorption. Avoid taking with calcium, coffee, or tea (which reduce absorption).
Vitamin B12
Who it helps: People with B12 deficiency (common in vegans, older adults, and those on metformin or PPIs)
Evidence level: Very strong (for deficient individuals)
Vitamin B12 is essential for red blood cell formation and neurological function. Deficiency causes fatigue, weakness, difficulty concentrating, and in severe cases, nerve damage. It is common in vegans (B12 is found almost exclusively in animal products), adults over 50 (reduced absorption), and people taking certain medications (metformin, proton pump inhibitors).
Supplementing B12 when you are deficient resolves the fatigue. But here is what the supplement industry will not emphasize: if your B12 levels are normal, taking more B12 will not give you extra energy. Your body excretes excess B12 in urine. Those mega-dose 5,000 mcg B12 supplements marketed as "energy boosters" are expensive urine for people with normal B12 levels.
A blood test for serum B12 (and ideally methylmalonic acid, a more sensitive marker) can confirm whether you are deficient. If you are, supplementation at 1,000-2,000 mcg/day of methylcobalamin will typically correct the deficiency within weeks to months. See our vitamin B12 scorecard for product comparisons.
Vitamin D
Who it helps: People with vitamin D deficiency (surprisingly common)
Evidence level: Moderate for fatigue specifically
Vitamin D deficiency is extremely common, affecting an estimated 42% of US adults. Fatigue is a recognized symptom of deficiency, though it is not always the presenting complaint. Several studies have found that correcting vitamin D deficiency improves fatigue scores, though the evidence is less dramatic than for iron deficiency.
A 2016 RCT in Medicine found that a single high dose of vitamin D significantly improved fatigue scores in deficient participants over 4 weeks. A 2019 systematic review found that vitamin D supplementation improved fatigue in people with various chronic conditions associated with low vitamin D levels.
Getting your 25-hydroxyvitamin D level tested is the smart approach. Levels below 30 ng/mL are considered insufficient, and below 20 ng/mL is deficient. If you are low, 2,000-4,000 IU of D3 daily is a standard corrective dose. Check our vitamin D3 scorecard for product comparisons.
Supplements That Help Regardless of Deficiency Status
Creatine
Who it helps: Most people, through cellular energy production
Evidence level: Strong
Creatine is best known for muscle performance, but it works at a more fundamental level: it increases the availability of ATP (adenosine triphosphate), which is the primary energy currency of every cell in your body. This means creatine can improve not just physical performance but also cognitive energy, particularly under conditions of stress, sleep deprivation, or high mental demand.
A 2018 systematic review and meta-analysis found that creatine supplementation significantly improved short-term memory and reasoning, particularly in stressed or sleep-deprived individuals. A 2023 study found cognitive benefits in healthy adults during a mental fatigue protocol.
The energy benefit from creatine is not a stimulant effect. You will not feel a "buzz" or a sudden surge of energy. Instead, you may notice improved physical endurance, better cognitive performance under stress, and faster recovery from mental and physical exertion. The effect builds over days to weeks as creatine stores in muscle and brain tissue reach saturation.
Effective dose: 3-5 grams of creatine monohydrate per day. No loading phase is necessary (though loading with 20 grams/day for 5-7 days reaches saturation faster). Creatine monohydrate is the best-studied and cheapest form. No other form (HCl, buffered, etc.) has been shown to be superior. See our creatine monohydrate scorecard for product comparisons.
At $0.03-$0.10/day for a quality creatine monohydrate product, this is one of the best value propositions in the entire supplement market.
CoQ10 / Ubiquinol
Who it helps: Adults over 40, people on statins, those with fatigue of unknown origin
Evidence level: Moderate
Coenzyme Q10 is essential for mitochondrial energy production. Your body produces it naturally, but production declines with age, and statin medications (among the most prescribed drugs in America) significantly reduce CoQ10 levels.
A 2014 systematic review in the Journal of Clinical Pharmacy and Therapeutics found that CoQ10 supplementation reduced fatigue and improved physical performance in several clinical contexts. For statin users specifically, a 2018 meta-analysis found that CoQ10 supplementation significantly reduced statin-associated muscle symptoms (which include fatigue and weakness).
In generally healthy, younger adults with normal CoQ10 levels, the evidence for an energy benefit is weak. But for adults over 40, statin users, and people with unexplained fatigue, CoQ10 is a reasonable option with a strong safety profile.
The form matters: ubiquinol (the reduced form) is better absorbed than ubiquinone (the oxidized form), particularly in older adults. The effective dose is 100-200 mg/day of ubiquinol or 200-300 mg/day of ubiquinone. See our CoQ10/ubiquinol scorecard for product comparisons.
Skip These: Energy Supplements That Don't Deliver
B-complex vitamins (in non-deficient people)
B vitamins are involved in energy metabolism, which is why they are marketed as energy supplements. But being involved in a metabolic process does not mean that adding more of it speeds up that process. If you are not deficient in B vitamins, taking a B-complex will not increase your energy. It is like pouring extra motor oil into a car that already has enough. Multiple systematic reviews have failed to find consistent energy benefits from B-vitamin supplementation in non-deficient adults.
Rhodiola rosea
Rhodiola is an adaptogenic herb marketed for fatigue and mental performance. A few small studies have shown modest benefits for stress-related fatigue, but the overall evidence base is small, the study quality is mixed, and the effect sizes are modest. A 2012 systematic review found that the existing studies were too heterogeneous and low-quality to draw firm conclusions. Rhodiola is not harmful, but the evidence does not support the bold energy claims made by most brands.
Ginseng
Multiple meta-analyses of ginseng for fatigue and energy have produced inconsistent results. A 2018 Cochrane review found insufficient evidence to support ginseng for enhancing physical performance. Some studies show small benefits for subjective fatigue, but the effects are inconsistent across trials and the optimal dosing is unclear. The evidence is stronger for Panax ginseng than American ginseng, but even for Panax, the overall picture is unconvincing.
Cordyceps
Cordyceps mushroom is heavily marketed for energy and athletic performance, primarily based on animal studies and a famous (and methodologically questionable) story about Chinese Olympic athletes. A 2020 systematic review of human studies found mixed results, with some studies showing modest aerobic performance benefits and others showing none. The evidence is insufficient to recommend cordyceps as an energy supplement.
PQQ (Pyrroloquinoline quinone)
PQQ is marketed as a mitochondrial support supplement. While it shows interesting results in cell and animal studies for mitochondrial biogenesis, human clinical data is extremely limited. A few small studies show possible cognitive benefits, but no well-designed human trials have demonstrated meaningful energy improvements. At $0.50-$1.00/day, PQQ is expensive for a supplement with minimal human evidence.
The Practical Approach
If you are experiencing persistent fatigue, here is the evidence-based approach:
- Get blood work. Test ferritin (iron stores), B12, vitamin D, and a complete metabolic panel. This is the single most useful step because it identifies causes that are cheap and easy to fix
- Fix any deficiencies with targeted supplementation at clinically effective doses
- Consider creatine (3-5 g/day) regardless of blood work. It is cheap, safe, well-studied, and benefits cellular energy production broadly
- Consider CoQ10 if you are over 40 or on statins
- Investigate non-supplement causes: sleep quality, sleep apnea, stress, thyroid function, depression, and dietary quality are all more common causes of fatigue than nutrient deficiency
Use our comparison tool to find the best-value products for any supplements you decide to try, and check our scoring methodology to understand how we evaluate products on evidence, quality, cost, and transparency.