The one supplement with a decent case for routine use in people who genuinely get little sun. A blood test settles it in a way guessing cannot.
Who this is actually for
People with little sun exposure, darker skin at northern latitudes, older adults, anyone housebound or covered outdoors, and anyone with a blood test showing deficiency. Cyprus sun helps, but indoor work and sunscreen mean deficiency is still common here.
What it is legally allowed to claim
Quoted from the EU register of authorised health claims, Regulation (EU) 432/2012. A product may only make these claims if it supplies enough of the nutrient to qualify.
- Vitamin D contributes to the maintenance of normal bones
- Vitamin D contributes to normal blood calcium levels
How much is too much
EFSA tolerable upper intake level 100 micrograms (4000 IU) per day for adults, set 2023.
Doses far above the upper limit cause high blood calcium. If you take thiazide diuretics or digoxin, or have sarcoidosis or kidney stones, ask before starting.