Supplements for fatigue and low energy

Written to our editorial standards · reviewed against published research· Updated 2 Jun 2026
Energy & fatigue

Persistent fatigue is most often linked to low iron, vitamin B12, vitamin D, or an underactive thyroid, the first things worth checking before reaching for a stimulant.

Iron and B12 are needed to carry oxygen and produce energy inside your cells, so a shortfall in either is a classic cause of tiredness, especially in menstruating women, vegans, and older adults. Low vitamin D and low thyroid hormone also commonly show up as flat, heavy fatigue, and magnesium supports the energy-producing steps inside the cell.

Nutrients commonly linked

Iron Bisglycinate
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Methyl-B12
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Vitamin D3 + K2
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Magnesium Glycinate
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Methylfolate
See the guide →

Biomarkers worth checking

These are the blood tests most relevant here. Knowing your numbers tells you whether a supplement is the right answer.

FerritinVitamin B12Vitamin D (25-OH)TSHHbA1c
When to see a doctor

See a doctor if fatigue is severe, sudden, or comes with weight loss, breathlessness, a racing heart, or feeling faint, since these can signal anaemia, thyroid disease, or other conditions that need testing, not a supplement.

Beyond supplements

Sleep, daylight, hydration, and steady meals move energy more than any pill; treat supplements as a fix for a measured shortfall.

Common questions

What supplements help with fatigue and low energy?
Persistent fatigue is most often linked to low iron, vitamin B12, vitamin D, or an underactive thyroid, the first things worth checking before reaching for a stimulant. The nutrients most often linked are Iron Bisglycinate, Methyl-B12, Vitamin D3 + K2, Magnesium Glycinate, Methylfolate.
Which deficiencies are associated with fatigue and low energy?
Iron and B12 are needed to carry oxygen and produce energy inside your cells, so a shortfall in either is a classic cause of tiredness, especially in menstruating women, vegans, and older adults. Low vitamin D and low thyroid hormone also commonly show up as flat, heavy fatigue, and magnesium supports the energy-producing steps inside the cell.
When should I see a doctor about fatigue and low energy?
See a doctor if fatigue is severe, sudden, or comes with weight loss, breathlessness, a racing heart, or feeling faint, since these can signal anaemia, thyroid disease, or other conditions that need testing, not a supplement.

Explore further

Find out what's actually low

Upload your bloodwork and we'll read the relevant markers, or take the quiz for a personalised stack.

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Educational use only, not medical advice, diagnosis, or treatment. Symptoms have many possible causes, and the nutrients here are commonly associated with this symptom, not a guaranteed fix. Always consult a qualified clinician, especially if symptoms are severe, persistent, or new.