The Best Vitamins & Supplements for Energy (Backed by Science)

Key takeaways

• The clearest benefits come from fixing a deficiency, not from megadosing.¹

• Get tested before taking iron. Don’t take it “just in case”.³

• Ginseng and royal jelly show promise.^4,8

• Persistent fatigue can have medical causes that no supplement will fix.⁶

Why vitamins matter for energy (and where the hype goes wrong)

Vitamins don’t contain energy. Your food does. What B vitamins and minerals like iron and magnesium do is act as the helpers that let your cells convert food into usable fuel. A large narrative review of the biochemical and clinical evidence found that the clearest benefits show up in people with low intake or low blood levels.¹

That is why the best vitamin for energy is the one you’re low in, and why a blood test is a better first step than a shopping trip.

It’s 3 p.m., and your battery is at 4%

Picture Dana. She sleeps seven hours, drinks her coffee, and still hits a wall every afternoon. Her words are on the tip of her tongue, her focus has gone soft, and the to-do list stares back at her. So she does what most of us do: she searches “vitamins for energy” and ends up at a pharmacy shelf, staring at a hundred bottles that all promise to fix it.

Before Dana buys anything, here is what the science says.

The best supplements for energy, ranked by evidence

1. Vitamin B12 for energy: the classic “tired and weak” culprit

A B12 deficiency can cause fatigue and weakness. Some people are at higher risk: adults over 50, vegans, people with celiac or Crohn’s disease, and anyone who has had stomach surgery.² If you’re in one of those groups, mention it to your doctor and ask about testing.

2. Iron for fatigue, if you’re low

This is where the trial evidence gets striking. In a randomised trial of 198 women with low iron stores but no anaemia, 80 mg of iron daily for 12 weeks cut fatigue by 48%, compared with 29% on placebo.³ Two lessons: results took weeks, not days, and the women were tested first. Iron isn’t harmless in excess, so confirm you need it.

3. Vitamin D, if your levels are low

Vitamin D is best known for keeping bones strong, and low levels can weaken them.¹⁰ It may matter for tiredness too. In a randomised trial of 120 otherwise healthy adults who were tired and low in vitamin D, a single large dose of vitamin D3 eased fatigue more than placebo after four weeks: 72% felt better, compared with 50% on placebo.⁹ As with iron, everyone in the trial was tested first. Too much vitamin D raises calcium in the blood, which can harm the kidneys, and it almost always comes from supplements, so check your level before you take it.¹⁰

4. B vitamins for energy (B1, B2, B3, B6)

These vitamins are essential to energy metabolism, but extra amounts help mostly when your intake is low.¹ If your diet is varied, a high-dose B-complex is unlikely to turn you into a morning person. If your diet is restricted, it may be worth discussing with a professional.

5. Magnesium for tiredness

Fatigue and weakness are among the early signs of magnesium deficiency.⁵ If you suspect you’re running low, see our guide to Magnesium Glycinate Benefits.

6. Ginseng for energy

Ginseng is an adaptogen, a plant traditionally used to help the body handle stress and fatigue. A 2022 systematic review and meta-analysis examined ginseng supplements for disease-related fatigue.⁴ The evidence is intriguing but not conclusive, so think of ginseng as an optional experiment rather than a foundation. Short-term use of up to six months appears safe for most adults⁷, but it may affect blood sugar and blood clotting, so check with your doctor first if you take diabetes or blood-thinning medicines, and avoid it in pregnancy.⁷

7. Royal jelly

A recent crossover trial in athletes found that royal jelly supplementation improved endurance and mitochondrial biogenesis, the process by which cells build new energy-producing structures.⁸ It’s an exciting early signal, but the participants were athletes, so we can’t assume the same effect for everyday tiredness.

8. CoQ10 (coenzyme Q10)

CoQ10 is a substance your body makes on its own, with the highest levels in the heart, liver, kidneys and pancreas.¹⁶ It is often sold for energy. A systematic review of 16 studies found that 10 reported less fatigue with CoQ10, but most of the people studied were living with a condition such as fibromyalgia, multiple sclerosis or heart failure, or with tiredness linked to statin medicines. The authors called for larger and longer trials.¹⁵ No serious side effects have been reported, though CoQ10 may interact with the blood thinner warfarin and with insulin, so talk to your doctor first if you take either.¹⁶

Food first: where each nutrient comes from

Before reaching for a bottle, it helps to know where these nutrients already sit in a normal diet.

• Vitamin B12: fish, meat, poultry, eggs, milk and dairy. It isn’t found in plant foods unless they’re fortified, so vegans can look for fortified cereals and nutritional yeast.¹³

• Iron: lean red meat, dark poultry meat, oysters, salmon, tuna, eggs, beans, dried fruit and fortified cereals. Iron from plants is harder to absorb, and foods rich in vitamin C, such as citrus, strawberries and tomatoes, help your body take it up.¹²

• Magnesium: dark green leafy vegetables, nuts such as almonds and cashews, beans, seeds, whole grains, tofu and bananas.¹⁴

• Vitamin D: fatty fish such as salmon, tuna and mackerel, with smaller amounts in egg yolks, cheese and beef liver. Your skin also makes it in sunlight.¹⁰

When to see a doctor

Supplements are a poor substitute for a diagnosis. Get medical advice if you have:⁶

• Unexplained fatigue, especially with fever, weight loss or night sweats.

• Confusion, dizziness or blurred vision (seek care right away).

• Trouble sleeping, or low mood.

Which tests to ask your doctor for

If tiredness has lasted for weeks, a few simple blood tests can point to the cause. Bring this list to your appointment:

• Ferritin, which shows how much iron your body has stored. It can pick up low iron early, especially if you have heavy periods.¹¹

• Vitamin B12, especially if you’re over 50, vegan, or have celiac or Crohn’s disease.²

• Vitamin D, the test that showed who could benefit in the trial above.⁹

• Thyroid function, since an underactive or overactive thyroid can cause fatigue.⁶

• A blood count to check for anaemia.⁶

Your doctor will choose what fits your symptoms, but asking about these makes the visit count.

What about brain fog?

Dana’s foggy afternoons are common, and brain fog isn’t a diagnosis. The things that commonly cause fatigue, including poor sleep, low iron, thyroid problems, depression and some medicines, can also leave you feeling foggy.⁶ That’s good news in one sense: many of these causes can be identified and treated.

Curious how your liver and brain communicate? Read The Liver–Brain Axis.

References

1. Tardy AL, Pouteau E, Marquez D, Yilmaz C, Scholey A. Vitamins and minerals for energy, fatigue and cognition: a narrative review of the biochemical and clinical evidence. Nutrients. 2020;12(1):228. doi:10.3390/nu12010228. PMID: 31963141.

2. Office of Dietary Supplements. Vitamin B12: fact sheet for consumers. NIH. https://ods.od.nih.gov/factsheets/VitaminB12-Consumer/

3. Vaucher P, Druais PL, Waldvogel S, Favrat B. Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial. CMAJ. 2012;184(11):1247-1254. PMID: 22777991.

4. Zhu J, Xu X, Zhang X, et al. Efficacy of ginseng supplements on disease-related fatigue: a systematic review and meta-analysis. Medicine (Baltimore). 2022;101(26):e29767. PMID: 35776997.

5. Office of Dietary Supplements. Magnesium: fact sheet for health professionals. NIH. https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/

6. MedlinePlus. Fatigue. National Library of Medicine. https://medlineplus.gov/ency/article/003088.htm

7. National Center for Complementary and Integrative Health. Asian ginseng. NCCIH. https://www.nccih.nih.gov/health/asian-ginseng

8. Pasdar Y, Tadibi V, Sadeghi E, et al. Royal jelly supplementation improves endurance and mitochondrial biogenesis in athletes: a crossover trial. Food Sci Nutr. 2025;13(7):e70497. PMID: 40678328.

9. Nowak A, Boesch L, Andres E, et al. Effect of vitamin D3 on self-perceived fatigue: a double-blind randomized placebo-controlled trial. Medicine (Baltimore). 2016;95(52):e5353. PMID: 28033244.

10. MedlinePlus. Vitamin D. National Library of Medicine. https://medlineplus.gov/ency/article/002405.htm

11. MedlinePlus. Ferritin blood test. National Library of Medicine. https://medlineplus.gov/lab-tests/ferritin-blood-test/

12. MedlinePlus. Iron in diet. National Library of Medicine. https://medlineplus.gov/ency/article/002422.htm

13. MedlinePlus. Vitamin B12. National Library of Medicine. https://medlineplus.gov/ency/article/002403.htm

14. MedlinePlus. Magnesium in diet. National Library of Medicine. https://medlineplus.gov/ency/article/002423.htm

15. Mehrabani S, Askari G, Miraghajani M, Tavakoly R, Arab A. Effect of coenzyme Q10 supplementation on fatigue: a systematic review of interventional studies. Complement Ther Med. 2019;43:181-187. PMID: 30935528.

16. National Center for Complementary and Integrative Health. Coenzyme Q10. NCCIH. https://www.nccih.nih.gov/health/coenzyme-q10