Best Supplements for Energy and Fatigue: Test First, Then Supplement
B12 and iron fix fatigue only when you're deficient. Caffeine helps alertness short-term; creatine and rhodiola have limited evidence. See what to test.
By the editorial team · Updated Oct 14, 2026 · 2 sources cited
The best supplements for energy correct a cause of fatigue. Iron and vitamin B12 restore energy in people who are deficient, which is why a blood test comes first. Caffeine reliably boosts alertness short-term. Creatine and rhodiola have limited evidence. B12 shots or energy blends won't help if your levels are normal.
Evidence-ranked options
| Supplement | Evidence | Typical dose | Notes |
|---|---|---|---|
| Iron (if deficient) | A | As advised after a blood test | Iron deficiency is a common, treatable cause of fatigue. |
| Vitamin B12 (if deficient) | A | As advised | Common in vegans, over 50s and metformin users. |
| Caffeine | B | Up to 400 mg a day | Short-term alertness; can disrupt sleep. |
| Creatine | C | 3–5 g a day | May reduce mental fatigue, especially when sleep-deprived. |
| Rhodiola | C | 200–400 mg in the morning | Mixed evidence for fatigue. |
A: strong · B: moderate · C: limited or mixed · D: good evidence of no benefit. See the evidence database.
Check these first
Use our deficiency risk check to see which tests to ask about. Sleep 7–9 hours, stay active, and limit alcohol: these affect energy more than any supplement.
Ingredient guides
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Frequently asked questions
Why am I always tired?
Common causes include poor sleep, sleep apnea, anemia, thyroid problems, depression, diabetes and medication side effects. See a doctor if tiredness lasts more than a few weeks.
Do B vitamins give you energy?
Only if you're low in them. They don't act as stimulants.
Sources
Educational content, not medical advice. Read our medical disclaimer.