By goal
Evidence-Backed Supplements for Energy and Fatigue
Persistent fatigue is most often driven by sleep, stress, or a treatable deficiency (iron, B12, vitamin D) rather than something a pill fixes on its own. Here we grade the supplements people take for energy, separating the few with real human evidence from the popular but unproven. None of this treats an underlying medical cause, and unexplained tiredness is worth discussing with a clinician.
| Supplement | Evidence for this goal | Typical dose | Key caution | Studies |
|---|---|---|---|---|
| Caffeine | Strong | 3–6 mg/kg pre-exercise for ergogenic effect; ≤400 mg/day generally safe… | Safe ≤400 mg/day for most adults. | 22 |
| Creatine Monohydrate | Strong | 3–5 g/day. Optional loading: 20 g/day (split) for 5–7 days. | Very safe. | 21 |
| Folate / Folic Acid | Strong | 400-800 mcg/day for anyone who could become pregnant (start >=1 month b… | Folic acid is generally very safe at recommended doses; the tolerable upper intake level fo… | 14 |
| Iron | Strong | Treatment ~40–60 mg elemental; alternate-day dosing may absorb better.… | Constipation, nausea and dark stools are common. | 18 |
| Vitamin B12 | Strong | 2.4 µg/day RDA; deficiency corrected with high oral (500–1,000 µg) or i… | Very safe; excess excreted. | 25 |
| Vitamin D3 | Strong | 1,000–2,000 IU/day maintenance; higher to correct deficiency under test… | Tolerable upper limit ~4,000 IU/day for most adults; toxicity (hypercalcemia) occurs with c… | 18 |
| Ashwagandha | Moderate | 300–600 mg/day of root extract (standardized to 5% withanolides), often… | Avoid in pregnancy (traditionally abortifacient) and while breastfeeding. | 20 |
| Beetroot / Dietary Nitrate | Moderate | ~6-13 mmol (≈310-800 mg) inorganic nitrate per day, typically as 1-2 co… | Generally well tolerated. | 20 |
| Blackcurrant | Moderate | About 1 cup fresh berries (110-150 g); ergogenic/eye-health trials use… | Generally safe as food. | 11 |
| Grapefruit | Moderate | A typical serving is half a medium grapefruit (~123 g) or one whole fru… | Clinically important: grapefruit furanocoumarins irreversibly inhibit intestinal CYP3A4, ra… | 8 |
| L-Theanine | Moderate | 100–200 mg; often paired 1:2 with caffeine (e.g. 100mg theanine + 50mg… | Very safe, no known serious side effects. | 18 |
| Magnesium | Moderate | 200–400 mg elemental/day. Glycinate & citrate absorb best; oxide is poo… | Safe. | 22 |
| Panax Ginseng | Moderate for this goal | 200–400 mg/day standardized extract. | Generally safe short-term. | 18 |
| Pomegranate | Moderate | A common serving is about 1 cup of arils (174 g) or roughly half a frui… | Generally safe as a food. | 9 |
| Breadfruit | Preliminary | 1 cup cooked cubes (~220 g) as a starch staple in place of rice, potato… | Generally safe as a food. | 10 |
| Coenzyme Q10 | Preliminary for this goal | 100–300 mg/day with fat for absorption. | Very safe. | 21 |
| Durian | Preliminary | Roughly 1-2 segments (~40-100 g pulp); a portion delivering 50 g carboh… | Energy- and fat-dense for a fruit (~147 kcal and 5 g fat per 100 g), so large portions add… | 11 |
| Lime | Preliminary | 1 medium lime (~67 g) or 30–60 mL juice; 1–2 limes daily as a culinary… | Highly acidic juice can erode tooth enamel and aggravate reflux or mouth ulcers. | 12 |
| Maca | Preliminary | 1.5–3 g/day of dried root powder (as used in trials). | Generally well tolerated as a food. | 17 |
| Nicotinamide Riboside (NR) | Preliminary | 250–1000 mg/day orally (trials have used up to 2000–3000 mg/day); commo… | Generally well tolerated; most common adverse effects are mild headache, flushing or feelin… | 18 |
| NMN (Nicotinamide Mononucleotide) | Preliminary | 250–600 mg once daily by mouth; trials have used up to 900 mg/day. Bloo… | Short-term oral NMN (up to 900 mg/day for 1-3 months) was well tolerated in trials, with no… | 13 |
| Schisandra | Preliminary for this goal | 1–3 g dried berries or ~500 mg standardized extract/day. | Generally well tolerated. | 16 |
| Shilajit | Preliminary for this goal | 250–500 mg/day of a PURIFIED, lab-tested extract. Never use raw shilaji… | ⚠ Unpurified shilajit can contain dangerous heavy metals (lead, arsenic). | 16 |
| Tongkat Ali | Preliminary | 200–400 mg/day standardized extract. | Limited long-term data. | 15 |
| Astragalus | Mixed for this goal | 9–30 g dried root as decoction (traditional); 500–1,000 mg standardized… | Generally well tolerated. | 20 |
| Coconut | Mixed | 1 cup shredded fresh meat (~80 g) or ~240 mL coconut water; coconut oil… | Very high in saturated fat (coconut oil ~80-90%; meat ~89% of its fat): major heart and die… | 9 |
| Cordyceps | Mixed | 1–3 g/day of cultivated extract (Cs-4 / Cordyceps militaris). | Generally safe. | 19 |
| Rhodiola Rosea | Mixed for this goal | 200–600 mg/day standardized to 3% rosavins / 1% salidroside. | Well tolerated. | 19 |
Supplements for Energy and Fatigue — common questions
Which supplement has the best evidence for energy and fatigue?
The best-supported options are the ones that correct an actual deficiency: iron, vitamin B12, vitamin D3 and folate all carry strong evidence, but mainly in people who are genuinely low. If your bloodwork is normal, the strongest evidence for a real lift belongs to caffeine, and to creatine monohydrate for physical fatigue. Nothing here reliably fixes tiredness in someone who is not deficient.
How much should I take and how long until I feel less tired?
Timelines depend entirely on what you are fixing. Iron is usually treated with roughly 40-60 mg elemental iron, and alternate-day dosing may absorb better; levels and symptoms recover over weeks to months. B12 deficiency is corrected with 500-1,000 mcg orally or by injection. Caffeine works within an hour at 3-6 mg/kg. Creatine needs 3-5 g daily, or 20 g daily for 5-7 days to load.
Are energy supplements safe, and do they interact with medication?
Iron deserves respect: constipation, nausea and dark stools are common, and overdose is dangerous, being a leading cause of poisoning in children, so test before supplementing and store it safely. CoQ10 may reduce warfarin's effectiveness. Ashwagandha should be avoided in pregnancy and breastfeeding and often causes drowsiness or stomach upset. Keep caffeine under 400 mg daily, or 200 mg in pregnancy. Please check with your doctor or pharmacist first.
Is CoQ10 worth taking for tiredness, or is it hype?
Honest answer: it sits at moderate, not strong, evidence, alongside ashwagandha, magnesium and L-theanine. CoQ10 at 100-300 mg with fat is popular with statin users and is very safe, but it is not a proven fatigue cure. Ashwagandha targets stress rather than energy itself, and L-theanine mostly smooths caffeine's edge. None of them substitutes for finding and treating low iron, B12 or vitamin D.