Common questions
Constant tiredness and fatigue
Updated: October 25, 2026
Find the cause of constant fatigue first — a supplement shouldn't mask it.
Common causes: too little sleep, too few calories (crash dieting), overtraining, low iron, B12 or vitamin D, thyroid problems.
- Tests: full blood count, ferritin, B12, vitamin D, TSH.
- Sleep 7–9 hours and cut training volume for a while.
- Eat enough calories and carbs, especially on training days.
If a test shows a deficiency, I'll help you pick the right supplement (iron, B12, D3).
General sports-nutrition guidance, not medical advice. If you have a condition, are pregnant or take medication, check with your doctor first.