Vitamins, Herbs and Supplements for Energy: What Actually Works, Ranked by the Trials
The vitamins with the best evidence for energy are vitamin B12, iron and vitamin D, but with one condition that most energy-supplement articles leave out: they only work if you are low in them. Correcting an iron deficiency reduces fatigue by about half in trials; taking iron when your ferritin is normal does nothing except upset your stomach. The same is true of B12 and D. Beyond those, the supplements with real trial evidence for fatigue in people who are not deficient are rhodiola, panax ginseng, creatine and coenzyme Q10, and each helps a particular kind of tiredness.
This guide is for adults who are persistently tired without an obvious cause: dragging through afternoons, needing caffeine to function, or recovering slowly from exercise. The first step is not a supplement but a blood test. Ask your doctor for a full blood count, ferritin, vitamin B12, folate, vitamin D, thyroid function (TSH) and HbA1c; in the UK and most countries these are routine, and together they pick up the common fixable causes: iron deficiency, B12 deficiency, low vitamin D, an underactive thyroid and early diabetes. Treating what the test finds beats guessing with a multivitamin every time.
See a doctor rather than a supplement shelf if fatigue has lasted more than a month, if it comes with weight loss, fever, night sweats, breathlessness, swollen glands or low mood, or if you snore and wake unrefreshed (sleep apnoea is the most under-diagnosed cause of exhaustion). Chronic fatigue syndrome, hypothyroidism and depression all present as 'low energy', and none of them responds to an energy vitamin.
Quick answer
- Iron — halves fatigue in iron-deficient women even without anaemia; useless if ferritin is normal
- Vitamin B12 — reverses fatigue from deficiency, which is common after 50, on metformin, and in vegans
- Vitamin D — improved fatigue scores in a placebo-controlled trial of deficient adults; check your level first
- Rhodiola rosea — reduces stress-related fatigue and improves concentration within 1–4 weeks
- Creatine — boosts physical and mental performance, especially in vegetarians and the sleep-deprived
- Coenzyme Q10 — reduces fatigue in a 2022 meta-analysis, most clearly in statin users and heart failure
The 10 best herbs and supplements for energy
Ranked by the strength of human evidence. Strong = multiple trials or a meta-analysis. Moderate = a few small trials. Preliminary = early or animal data.
Iron
Strong evidenceIn a 12-week RCT of 198 menstruating women with unexplained fatigue and low ferritin (under 50 µg/L) but no anaemia, 80 mg/day of iron reduced fatigue scores by 48% versus 29% on placebo. A 2018 systematic review of 10 trials confirmed oral iron reduces fatigue in iron-deficient non-anaemic adults. Iron deficiency affects around 1 in 4 menstruating women and is the most common fixable cause of tiredness. In people with normal iron stores there is no benefit and some harm, which is why the ferritin test matters.
- Key evidence
- 2012 RCT in iron-deficient non-anaemic women (Vaucher), 198 participants
- Studied dose
- 40–80 mg elemental iron/day (or every other day, which is absorbed as well with fewer side effects) as ferrous sulfate, fumarate or bisglycinate, for 12 weeks, then re-test ferritin
- Best for
- Menstruating women, endurance athletes, frequent blood donors, and anyone with a ferritin under 30–50 µg/L
- Cautions
- Do not take iron without a ferritin test: excess iron is harmful and masks haemochromatosis. Separate from thyroid medication, tetracyclines, quinolones and levodopa by 2–4 hours. Causes constipation and nausea in up to a third of people; keep away from children, where overdose is fatal.
B12 deficiency causes fatigue, breathlessness, pins and needles and low mood, and replacing it reverses those symptoms, often within weeks. Deficiency is common: around 6% of adults under 60 and up to 20% over 60, plus most long-term vegans, people on metformin or acid-suppressing drugs, and anyone with pernicious anaemia or gut surgery. In people with normal B12 levels, supplementation does nothing for energy: a 2023 systematic review found no benefit in non-deficient adults. The energy claim on B12 shots and gummies applies to the deficient only.
- Key evidence
- NIH Office of Dietary Supplements B12 fact sheet; a 2018 Cochrane review on B12 supplementation
- Studied dose
- 1,000 µg/day oral cyanocobalamin or methylcobalamin for deficiency (oral works as well as injections for most people); 25–100 µg/day for maintenance in vegans and over-50s
- Best for
- Vegans, over-50s, people on metformin or PPIs, and anyone with a serum B12 under 200–250 pmol/L
- Cautions
- Very safe even at high doses. Taking B12 without testing can mask a folate deficiency and delays diagnosis of pernicious anaemia, which needs lifelong treatment. Check B12 and folate before starting.
A 2016 double-blind RCT of 120 adults with fatigue and low vitamin D found a single 100,000 IU dose improved fatigue scores significantly more than placebo over 4 weeks, with the improvement tracking the rise in blood levels. Observational studies consistently link low vitamin D to fatigue and muscle weakness, and deficiency affects around 1 in 5 adults in northern countries in winter. As with iron and B12, trials in people with adequate levels show no energy benefit, and the large VITAL trial found no effect on most outcomes in the general population.
- Key evidence
- 2016 placebo-controlled RCT in vitamin D-deficient adults with fatigue (Nowak), 120 participants
- Studied dose
- 1,000–2,000 IU/day of vitamin D3 for maintenance; 4,000 IU/day for 8–12 weeks to correct deficiency, then re-test; take with a fatty meal
- Best for
- Anyone with a blood level under 50 nmol/L (20 ng/mL), especially in winter, with darker skin, or who covers up or stays indoors
- Cautions
- Doses above 4,000 IU/day long-term can raise blood calcium. Interacts with thiazide diuretics (calcium) and digoxin; needs supervision in sarcoidosis, hyperparathyroidism and kidney disease. Test before taking high doses.
A 28-day placebo-controlled RCT in 60 people with stress-related fatigue found 576 mg/day of a standardised extract improved fatigue, attention and the cortisol awakening response versus placebo. An earlier double-blind crossover study in 56 night-shift doctors found 170 mg/day reduced mental fatigue over 2 weeks, and a 2012 open trial found 400 mg/day improved fatigue within a week. A 2022 systematic review of 10 trials found consistent benefit for fatigue, with the caveat that most trials are small and products vary widely in quality.
- Key evidence
- 2009 placebo-controlled RCT in stress-related fatigue (Olsson), 60 participants
- Studied dose
- 200–600 mg/day of a root extract standardised to 3% rosavins and 1% salidroside, taken before noon, for 4–12 weeks
- Best for
- Burnout, shift work, exam periods, and fatigue that comes with stress and poor concentration
- Cautions
- Can cause jitteriness and insomnia if taken late. Possible interactions with SSRIs, MAOIs, and blood-pressure and diabetes drugs. Avoid in bipolar disorder and pregnancy.
Creatine
Strong evidenceThe best-studied sports supplement in existence, with hundreds of trials showing increased strength, power and training capacity at 3–5 g/day. Beyond the gym, a 2018 systematic review found creatine improves short-term memory and reasoning, most clearly in vegetarians and older adults, and a 2024 trial found a single high dose reduced the cognitive fatigue of sleep deprivation. For fatigue specifically, it helps the kind that comes with low muscle energy reserves: hard training, low meat intake, ageing and recovery from illness.
- Key evidence
- 2017 International Society of Sports Nutrition position stand (Kreider), reviewing several hundred RCTs
- Studied dose
- 3–5 g/day of creatine monohydrate, any time of day, with no need for a loading phase; effects build over 2–4 weeks
- Best for
- Vegetarians and vegans, people over 50 losing muscle, anyone training hard, and the chronically sleep-deprived
- Cautions
- Safe in healthy kidneys at 3–5 g/day over years of study, but check with a doctor if you have kidney disease or take nephrotoxic drugs. Expect 1–2 kg of water weight in the first fortnight. It raises creatinine on blood tests, which can be misread as kidney trouble; tell your doctor you take it.
Coenzyme Q10
Moderate evidenceA 2022 meta-analysis of 13 RCTs (1,126 people) found CoQ10 significantly reduced fatigue, with larger effects at higher doses and in people with fatigue-related illness. The clearest wins are in statin users, where 100–200 mg/day reduces muscle symptoms, in heart failure (the Q-SYMBIO trial found 300 mg/day reduced major cardiovascular events over 2 years) and in fibromyalgia. A 2008 Japanese trial found 300 mg/day reduced fatigue and improved exercise performance in healthy adults after 8 days, though the effect in healthy people is small.
- Key evidence
- 2022 meta-analysis of 13 RCTs (Tsai), 1,126 participants
- Studied dose
- 100–300 mg/day of ubiquinol or ubiquinone with a fatty meal, for at least 8–12 weeks; higher doses (300 mg) for statin myalgia or heart failure
- Best for
- Statin users with tired, aching muscles, people over 60, and those with heart failure or fibromyalgia
- Cautions
- Can reduce the effect of warfarin (structurally similar to vitamin K); monitor INR. May lower blood pressure and blood sugar slightly. Very well tolerated otherwise.
A 2018 systematic review of 10 RCTs found ginseng modestly reduced fatigue, with the best evidence in people with chronic illness and cancer-related fatigue. A 4-week RCT in 90 adults with idiopathic chronic fatigue found 2 g/day of Korean red ginseng improved fatigue scores and oxidative stress markers, and an 8-week trial of 2,000 mg/day American ginseng in 364 cancer patients improved fatigue versus placebo. Effects are modest and appear after 2–4 weeks; a cup of ginseng tea is not the tested dose.
- Key evidence
- 2018 systematic review of 10 RCTs for fatigue (Arring)
- Studied dose
- 200–400 mg/day of an extract standardised to 4–7% ginsenosides, or 1–2 g of dried root, in the morning, for 4–12 weeks with breaks
- Best for
- Chronic fatigue without a found cause, fatigue during illness, and mental tiredness
- Cautions
- Lowers blood glucose (monitor with diabetes drugs) and reduces the effect of warfarin. Can raise blood pressure and cause insomnia; avoid combining with high caffeine. Avoid in hormone-sensitive conditions and pregnancy.
A 12-week RCT in 20 healthy older adults found 333 mg three times daily of a cultured Cordyceps sinensis (Cs-4) extract improved exercise capacity (ventilatory and metabolic thresholds by about 10%) versus placebo, and a 3-week 2017 trial in 28 young adults found a cordyceps-containing mushroom blend improved VO2max and time to exhaustion. A 2010 trial in 20 older adults also found improved exercise performance. Trials in athletes are mixed and all are small, so it is Preliminary despite the consistent direction.
- Key evidence
- 2010 placebo-controlled RCT of Cs-4 in older adults (Chen), 20 participants
- Studied dose
- 1–3 g/day of a Cordyceps militaris or Cs-4 fruiting-body or mycelium extract, for 3–12 weeks
- Best for
- Older adults and recreational athletes wanting better exercise tolerance
- Cautions
- May enhance the effect of anticoagulants and lower blood sugar. Avoid in autoimmune disease treated with immunosuppressants because of immune-stimulating effects. Choose a product tested for heavy metals.
Maca's clearest evidence is for libido and menopausal symptoms rather than energy. A 14-day crossover pilot in 8 trained cyclists found 2 g/day of maca improved 40 km time-trial performance, and a 12-week RCT in 175 adults found 3 g/day improved self-rated mood and energy at altitude. A 2016 systematic review found insufficient evidence for most claims. It is included because it is one of the most searched 'energy herbs', and it is safe, but the energy evidence is thin.
- Key evidence
- 2016 RCT of maca for mood and energy at altitude (Gonzales-Arimborgo), 175 participants
- Studied dose
- 1.5–3 g/day of gelatinised maca powder or extract, for 6–12 weeks
- Best for
- Low energy that comes with low libido or perimenopausal symptoms
- Cautions
- Avoid in hormone-sensitive conditions (breast, ovarian, prostate cancer, endometriosis) until better data exist. Raw maca can cause bloating; the gelatinised form is gentler. Little pregnancy data.
L-carnitine
Preliminary evidenceL-carnitine shuttles fatty acids into mitochondria. A 6-month RCT in 66 centenarians found 2 g/day reduced physical and mental fatigue and increased muscle mass versus placebo, and a 2013 trial in older adults found 2 g/day improved fatigue scores. Small trials show benefit in chronic fatigue syndrome and in fatigue from cancer treatment, while trials in healthy younger adults find no energy effect. It is a reasonable pick for the elderly and the chronically ill, not for the office-tired.
- Key evidence
- 2007 placebo-controlled RCT in centenarians (Malaguarnera), 66 participants
- Studied dose
- 1–2 g/day of L-carnitine or acetyl-L-carnitine, with food, for 8–24 weeks
- Best for
- Older adults with fatigue and muscle loss, and people with chronic illness or on dialysis
- Cautions
- Can cause a fishy body odour and nausea at higher doses. May increase the effect of warfarin and interact with thyroid medication. Gut bacteria convert carnitine to TMAO, a compound linked with heart disease, so long-term high doses in people with heart disease are a question mark.
How to choose
- Get the blood tests first (full blood count, ferritin, B12, folate, vitamin D, TSH, HbA1c). If ferritin is under 30–50, B12 under 250 pmol/L or vitamin D under 50 nmol/L, correct that and nothing else for 12 weeks; most people need to go no further.
- If your tests are normal and your fatigue is stress-shaped (foggy, overloaded, poor concentration), rhodiola in the morning is the first herb to try, with panax ginseng as the alternative.
- If your fatigue is physical (heavy legs, slow recovery, low strength), creatine at 3–5 g/day is the best-evidenced option, and it is cheap; add CoQ10 if you take a statin or are over 60.
- If you are vegan or vegetarian, you are more likely to be low in B12, iron and creatine, and trials show the biggest creatine effects in exactly that group; cover all three.
- If you need a same-day lift, nothing here beats 100–200 mg of caffeine plus 200 mg L-theanine; the picks above work over weeks, not hours.
- Do not buy a 'energy blend' with 15 ingredients at sub-trial doses. One supplement at the studied dose for 8–12 weeks, assessed honestly, beats a shotgun every time.
What to skip
B-complex or B12 for people with normal levels
The 'B vitamins give you energy' claim rests on their role in metabolism, not on trials: systematic reviews find no fatigue benefit in people who are not deficient. The bright yellow urine is the excess leaving your body.
Energy shots and 'natural' pre-workouts
The active ingredient is caffeine, typically 150–300 mg, dressed up with guarana, taurine and B vitamins that add nothing. You are paying ten times the price of a coffee for the same molecule plus a crash.
Shilajit and NAD+ precursors as energy boosters
Shilajit has one small trial on fatigue-related testosterone and one on exercise, both industry-funded, and products are often contaminated with heavy metals. NMN and NR raise NAD+ in blood but have not improved fatigue or physical performance in placebo-controlled trials. Both are expensive experiments.
Magnesium malate for energy (unless you are low)
The malate story (it feeds the Krebs cycle) is biochemistry, not evidence; there is no trial showing magnesium malate raises energy in people with normal magnesium. If you are low in magnesium, any well-absorbed form works, and the benefit is better sleep rather than more daytime energy.
Safety and when to see a clinician
- See a clinician if fatigue has lasted more than a month or comes with weight loss, fever, night sweats, breathlessness, swollen glands, bleeding, a new lump, or persistent low mood. Also if you snore loudly and wake unrefreshed, which points to sleep apnoea rather than a vitamin gap.
- Never take iron without a ferritin test. Iron overload (haemochromatosis) affects around 1 in 200 people of northern European descent and causes fatigue itself; iron supplements make it worse. Keep iron tablets away from children.
- Thyroid medication: iron, calcium and magnesium block levothyroxine absorption (separate by 4 hours), and ashwagandha and carnitine can alter thyroid levels. Hypothyroidism is a common cause of fatigue that needs treating, not supplementing around.
- Blood thinners and diabetes drugs: ginseng and CoQ10 reduce the effect of warfarin; ginseng, cordyceps and (in theory) rhodiola lower blood glucose. Tell your prescriber before adding any of them.
- Stimulant stacking: rhodiola, ginseng, and caffeine together can cause palpitations, high blood pressure and insomnia, which then worsens the fatigue you were treating. Use one at a time and none after midday.
- Pregnancy: iron, B12, vitamin D and folate at recommended doses are important, but rhodiola, ginseng, cordyceps, maca and high-dose vitamin D should be avoided.
What matters as much as any herb
- Sleep 7 to 9 hours on a consistent schedule: even mild chronic sleep restriction (6 hours) produces a cognitive deficit equivalent to two nights of total sleep deprivation after two weeks, and no supplement offsets it.
- Move daily: in people with persistent fatigue, a graded increase in walking or light exercise reduces fatigue more reliably than any supplement in trials, partly by improving sleep and mitochondrial function.
- Eat enough, and enough protein: under-eating (common in people trying to lose weight) and low protein intake are overlooked causes of tiredness, especially in women and older adults.
- Reset caffeine: if you need coffee to function, cut to one before noon for two weeks. Caffeine tolerance means the 4 p.m. cup is treating withdrawal, not fatigue, and it is fragmenting your sleep.
- Check alcohol: two drinks in the evening cuts REM sleep and raises next-day fatigue measurably; regular drinkers often find a dry month does more than any vitamin.
Frequently asked questions
What is the best vitamin for energy?
The one you are low in. For most tired people that means iron (ferritin), vitamin B12 or vitamin D, and a simple blood test tells you which. There is no vitamin that raises energy in someone with normal levels; the trials are consistently negative in non-deficient adults.
How do I know if I need B12 or iron for energy?
Ask your GP for ferritin (iron stores), a full blood count, and serum B12. Ferritin under 30 µg/L is deficient and under 50 is low enough to cause fatigue in menstruating women; B12 under about 200–250 pmol/L is low. Symptoms overlap (tiredness, breathlessness, pale skin, poor concentration) so guessing is unreliable.
Do energy supplements actually work?
Deficiency-correcting ones work very well in deficient people. Among the rest, rhodiola, panax ginseng, creatine and CoQ10 have placebo-controlled evidence for modest improvements in particular kinds of fatigue. Most 'energy' products rely on caffeine, and the B-vitamin-heavy ones do nothing measurable in people with normal levels.
What herbs give you energy without caffeine?
Rhodiola is the best evidenced, with trials showing reduced mental fatigue in stressed and shift-working adults within 1 to 4 weeks. Panax ginseng is next, with a systematic review supporting a modest effect. Cordyceps and eleuthero have smaller, mostly physical-performance evidence. None gives the immediate lift of caffeine; they work over weeks.
Why am I tired all the time even though I take vitamins?
Because the common causes of persistent tiredness are not vitamin gaps: short or poor-quality sleep, sleep apnoea, an underactive thyroid, depression, anaemia, too much caffeine or alcohol, under-eating, and chronic stress. A multivitamin does not touch any of those. Get the blood tests, look honestly at sleep and alcohol, and see a doctor if fatigue has lasted more than a month.
Is creatine good for energy if I do not go to the gym?
Yes, with caveats. Creatine improves cognitive performance in trials of vegetarians, older adults and the sleep-deprived, and it helps preserve muscle with ageing. In well-rested meat-eaters who do not exercise, the effect on daily energy is small. At 3–5 g/day it is cheap and safe enough that it is a reasonable experiment.
Can low vitamin D make you tired?
Yes. Low vitamin D is associated with fatigue and muscle weakness, and a placebo-controlled trial found that correcting deficiency improved fatigue over 4 weeks. Around 1 in 5 adults in northern countries is deficient by the end of winter. Check your level: if it is above 50 nmol/L, more vitamin D will not help your energy.
References
- 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)View source
- Houston BL, Hurrie D, Graham J, et al.. Efficacy of iron supplementation on fatigue and physical capacity in non-anaemic iron-deficient adults: a systematic review of randomised controlled trials. BMJ Open (2018)View source
- Vitamin B12: fact sheet for health professionals. NIH Office of Dietary SupplementsView source
- Iron: fact sheet for health professionals. NIH Office of Dietary SupplementsView source
- 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)View source
- Olsson EM, von Schéele B, Panossian AG. A randomised, double-blind, placebo-controlled, parallel-group study of the standardised extract SHR-5 of the roots of Rhodiola rosea in the treatment of subjects with stress-related fatigue. Planta Medica (2009)View source
- Arring NM, Millstine D, Marks LA, Nail LM. Ginseng as a treatment for fatigue: a systematic review. Journal of Alternative and Complementary Medicine (2018)View source
- Kreider RB, Kalman DS, Antonio J, et al.. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Journal of the International Society of Sports Nutrition (2017)View source
- Tsai IC, Hsu CW, Chang CH, Tseng PT, Chang KV. Effectiveness of coenzyme Q10 supplementation for reducing fatigue: a systematic review and meta-analysis of randomized controlled trials. Frontiers in Pharmacology (2022)View source
- Chen S, Li Z, Krochmal R, et al.. Effect of Cs-4 (Cordyceps sinensis) on exercise performance in healthy older subjects: a double-blind, placebo-controlled trial. Journal of Alternative and Complementary Medicine (2010)View source
- Malaguarnera M, Cammalleri L, Gargante MP, et al.. L-Carnitine treatment reduces severity of physical and mental fatigue and increases cognitive functions in centenarians: a randomized and controlled clinical trial. American Journal of Clinical Nutrition (2007)View source
- Vitamin D: fact sheet for health professionals. NIH Office of Dietary SupplementsView source
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Ask about energyThis guide is educational and is not medical advice. Herbs and supplements can interact with prescription medicines and are not regulated like drugs. Talk with a clinician or pharmacist before starting anything new, especially if you are pregnant, breastfeeding, have a chronic condition, or take medication.