Vitamin D Supplements

(142 products)

Vitamin D is one of the most widely taken supplements in the UK. The NHS advises everyone to consider taking 10mcg (400 IU) daily during autumn and winter, when UK sunlight levels are too low to support meaningful vitamin D production in the skin. Certain groups — including people with darker skin tones, those over 65, and anyone who is housebound or covers most of their skin outdoors — are advised to supplement year-round.

This collection includes tablets, softgels, sprays and liquid drops, from everyday maintenance doses through to higher-strength formulations, including D3 + K2 combinations and vegan vitamin D3 options.

Vitamin D doses appear on labels in two ways. Understanding the Label — IU vs mcg. Both refer to the same thing:

10mcg = 400 IU — the NHS daily reference amount
25mcg = 1,000 IU — a common everyday maintenance dose
50mcg = 2,000 IU — a widely used moderate-strength option
100mcg = 4,000 IU — the NHS advises not to exceed this daily without medical guidance

Knowing this conversion makes comparing products straightforward, whether a label shows mcg or IU.

For guidance on D3 vs D2, vegan options and the D3 + K2 combination, see the FAQs below.