Supplements and Fatigue: What to Know

Understanding fatigue

Fatigue means feeling low in energy or unusually exhausted. It can affect concentration, motivation and everyday tasks. An occasional tired day after poor sleep is different from persistent fatigue that does not improve with rest.

Sleep disruption, stress, insufficient food and recovery after illness can all contribute. Medicines and conditions such as anaemia, thyroid problems or sleep apnoea can also play a role. The symptom alone cannot tell you whether you need a supplement. [1]

Everyday steps to try

• Make sleep consistent. Keep regular bed and waking times and allow a quiet wind-down period. Notice whether late caffeine or alcohol disrupts your sleep.
• Eat enough, regularly. Include a mix of protein foods, whole grains or other starchy foods, vegetables and fruit. Restrictive eating can make it harder to meet nutrient needs.
• Move within your capacity. Gentle regular activity can be a useful starting point. Avoid pushing through exhaustion; if activity repeatedly makes symptoms substantially worse, seek advice.
• Look at the pattern. Keep a short record of sleep, meals, stress, medicines and symptoms to help identify what needs attention.

If small changes do not help, do not keep adding supplements in place of investigating the cause. [1]

When supplements may help

A supplement is most useful when it addresses a genuine shortfall or a specific need. Supporting normal energy metabolism does not mean that taking extra nutrients will provide an energy boost.

Iron: check whether you need it first

Iron deficiency anaemia can cause fatigue. Heavy menstrual bleeding and frequent blood donation are reasons to discuss iron status with a clinician. Testing and finding the reason for a deficiency matter before choosing a product. Iron is not a general-purpose energy supplement. [2]

Food sources include meat, beans, lentils and fortified cereals. Vitamin-C-rich foods can help absorption of plant iron. If a supplement is needed, the appropriate amount and follow-up depend on your situation. Explore iron forms and products →

Vitamin B12: particularly relevant to low intake or absorption

B12 deficiency can affect the blood and nervous system. A reliable source is especially important for people eating a vegan diet. Some digestive conditions and medicines, including metformin, can affect B12 status. Correcting a deficiency is different from taking extra B12 when levels are sufficient; extra B12 is not an established performance or energy enhancer in that situation. [3]

Some deficiencies need medical treatment rather than an ordinary supplement. New tingling, numbness or balance problems deserve assessment. Explore B12 forms and products →

Folate: consider it alongside B12

Folate deficiency can cause anaemia and fatigue. Leafy vegetables, beans and fortified foods contribute folate. Avoid treating unexplained fatigue with high-dose folic acid on your own: it can correct the anaemia of B12 deficiency while neurological damage continues. [4] Read the folate guide →

When to seek advice

Arrange an assessment if fatigue lasts for several weeks without a clear explanation, affects daily life or comes with weight loss, palpitations, unusual breathlessness or loud snoring and gasping during sleep. A clinician can decide which tests are appropriate. Seek urgent help for chest pain, severe breathlessness or fainting. Do not postpone assessment while trying an “energy” blend.

Product options to explore

Explore iron and B12 products when supplementation is appropriate for your needs. Choose the nutrient first, then compare form and amount.

More options: compare iron products · compare B12 products · Product Finder.

Sources

1. NHS: Tiredness and fatigue
2. NIH ODS: Iron — consumer fact sheet
3. NIH ODS: Vitamin B12 — health professional fact sheet
4. NIH ODS: Folate — consumer fact sheet

Updated 26 October 2026. General information for adults.