Before choosing a supplement, it's wise to ask yourself a few questions:

• How long have you been experiencing symptoms?A few days after a busy period is different from months of fatigue.
• What is your diet like?Vegan, vegetarian, omnivore, unbalanced?
• How old are you?Some deficiencies are more common in specific age groups.
• What medications are you taking?Antacids, metformin, birth control pills — these can affect nutrient levels.
• Do you have other signs besides fatigue?Pallor, shortness of breath, tingling, muscle cramps, poor sleep?

For persistent or severe fatigue: first get a blood test from your GP. This provides clarity and prevents you from supplementing for a deficiency that isn't there — or overlooking a deficiency that is present.

Step 2 — Which profile suits you? 

Below are six common profiles, with the most likely nutrient routes.

Profile A — "I am vegan or vegetarian and feel lethargic" 

Most likely candidates: B12, iron,B-complex,vitamin D, iodine. B12 is essential for almost every vegan. For menstruatingwomenbe extra vigilant about iron.

Profile B — "I'm 60+ and have less energy than before" 

Most likely candidates: B12, vitamin D, magnesium, possibly Q10 (ubiquinol). For those 60+, the natural absorption of B12 decreases (due to less stomach acid), skin production of vitamin D decreases, and endogenous Q10 production decreases. A combination of these three is a targeted foundation for many older people.

Profile C — "I exercise a lot and recover slowly" 

Most likely candidates: magnesium (loss through sweat, high muscle consumption), electrolytes (fluid balance), B-complex (energy metabolism), possibly iron (for endurance athletes). For broad sports support, a combination often works better than a single supplement.

Profile D — "I sleep poorly and am tired during the day" 

Most likely candidates: magnesium bisglycinate (with taurine), B-complex (nervous system), L-theanine (relaxation). The combination of poor sleep and daytime fatigue often indicates an underactive relaxation response — magnesium and L-theanine work specifically on this.

Profile E — "I use antacids (PPIs) or metformin" 

Most likely candidate: B12 — both medication groups reduce B12 absorption. For long-term use, a daily B12 supplement (500-2000 µg) is almost always advisable. Also consider a magnesium check (PPIs also lower magnesium status).

Profile F — "I have chronic stress and feel exhausted" 

Most likely candidates: magnesium (stress consumes magnesium, and magnesium relaxes), B-complex (B vitamins work on the nervous system), possibly adaptogens (rhodiola, ashwagandha — note EFSA status). For the combination of stress + exhaustion, magnesium bisglycinate with taurine is a commonly used foundation. Adaptogen option:Vitals Ashwagandha-KSMOrganic — a well-researched adaptogen form.

Profile G — "I am a woman 45+ in (peri-)menopause with lethargy" 

Most likely candidates: a complete formula tailored to this life stage, plus magnesium (sleep + stress) and possibly iron (for blood loss or if ferritin is low).Vitals Women's Formula Pro 45+is a complete formula with vitamins,mineralsand herbal extracts specifically for women 45+.