How to choose
Pick a plain D3 supplement at a sensible dose and take it with a meal that has some fat. Most adults do well around 600–800 IU/day for maintenance, with a 4,000 IU/day supplement upper limit; correcting a genuine deficiency sometimes needs more, short-term, under a clinician's guidance. The single most useful step is knowing your level — see our vitamin D lab-results interpreter, and our guides to vitamin D vs. D3, the best time to take it, and signs of deficiency.
Drops, softgels, and capsules all work — pick what you'll take consistently. Confirm third-party testing, skip mega-dose fat-soluble combos you don't need, and vet any product with the Supplement Trust Scorecard.
Frequently asked questions
How much vitamin D should a woman take?
General reference intakes are about 600 IU (15 mcg) a day for adults up to 70 and 800 IU (20 mcg) after, with a supplement upper limit of 4,000 IU (100 mcg) for adults. Correcting a diagnosed deficiency sometimes needs a higher short-term dose guided by a clinician and a blood test.
Is D3 better than D2?
For most people, yes — vitamin D3 (cholecalciferol) tends to raise and maintain blood levels a little more effectively than D2, and it's the common over-the-counter form. Vegan D3 made from lichen is available if you avoid animal products.
When is the best time to take vitamin D?
Take it with a meal containing some fat, which improves absorption; the exact time of day matters little. Consistency is what counts, so pick a moment you'll remember — often your largest meal.