• Start with food and a clear reason (GP/pharmacist advice or public-health guidance, not an ad)

• Know the rules: most vitamins are food supplements (FSAI), not medicines (HPRA)

• Read the label: form, amount per day, "do not exceed", allergens, who makes it

• Red flags: cure claims, secret formulas, mega-doses, pressure tactics

• Check interactions if you take medicines, are pregnant, or have a condition

• Prefer known Irish/EU pharmacies and retailers over unknown marketplace sellers