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The Best Vitamin D Supplements on Amazon

Updated By the HealthWorld editorial teamHow we pick

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Top picks at a glance

  1. 1
    Nature Made Vitamin D3 2000 IU

    Best everyday dose

    Nature Made Vitamin D3 2000 IU

    Vitamin D3 2000 IU · Form Softgel

  2. 2
    Sports Research Vegan Vitamin D3 + K2

    Best D3 + K2

    Sports Research Vegan Vitamin D3 + K2

    Vitamin D3 5,000 IU · Vitamin K2 100 mcg

  3. 3
    NOW Foods Vitamin D-3 5,000 IU

    Best high-dose value

    NOW Foods Vitamin D-3 5,000 IU

    Vitamin D3 5,000 IU · Serving 1 softgel

See all 4 picks and why ↓

Vitamin D3 on Amazon comes in very different strengths, and picking the right dose matters more than the brand. When we checked on October 31, 2026, Sports Research Vegan D3 + K2 was in the top 5 of Amazon's vitamins best sellers, so we compared it with Nature Made, NOW and Thorne by dose, form and testing.

Our picks

  1. Nature Made Vitamin D3 2000 IU

    #1Best everyday dose

    Nature Made Vitamin D3 2000 IU

    USP Verified vitamin D3 at 2000 IU in one small softgel a day. A moderate, affordable dose from one of America's most trusted vitamin brands.

    Vitamin D3 2000 IUForm SoftgeleBay Full facts →
  2. Sports Research Vegan Vitamin D3 + K2

    #2Best D3 + K2

    Sports Research Vegan Vitamin D3 + K2

    125 mcg (5,000 IU) of vegan vitamin D3 from lichen plus 100 mcg of vitamin K2 as MK-7, in a plant-based softgel with coconut MCT oil. In Amazon's vitamins top 5 when we checked.

    Vitamin D3 5,000 IUVitamin K2 100 mcgeBay Full facts →
  3. NOW Foods Vitamin D-3 5,000 IU

    #3Best high-dose value

    NOW Foods Vitamin D-3 5,000 IU

    5,000 IU (125 mcg) of vitamin D3 in a small softgel, 240 per bottle, from a family-owned brand that tests in its own labs.

    Vitamin D3 5,000 IUServing 1 softgeleBay Full facts →
  4. Thorne Vitamin D-5,000

    #4Best practitioner brand

    Thorne Vitamin D-5,000

    A simple, high-potency 5,000 IU vitamin D3 capsule, one a day, with no unnecessary fillers or artificial additives. Best used with your doctor's guidance.

    Vitamin D3 5,000 IUForm CapsuleeBay Full facts →
Amazon's live top 100 in Vitamins

What to look for

The dose: 2,000 vs 5,000 IU
The recommended intake for most adults is 600 IU a day (800 IU over 70), and the upper limit is 4,000 IU a day unless your doctor advises more. 2,000 IU is a common daily dose; 5,000 IU is best taken with your doctor's guidance and a blood test.
IU and mcg
Labels now list micrograms first: 50 mcg equals 2,000 IU and 125 mcg equals 5,000 IU. D3 (cholecalciferol) is the form most supplements use.
K2 and blood thinners
D3 + K2 combinations are popular, but vitamin K can affect blood thinners such as warfarin. If you take one, ask your doctor before choosing a K2 product.
USP Verified vs reviews
Nature Made's D3 is USP Verified, an independent check that the bottle contains what the label says. Star ratings can't tell you that.
Seller, count and date
Big bottles, like NOW's 240 softgels, keep the cost per day low. Buy from Amazon or the brand, and check the seal and best-by date when it arrives.

Frequently asked questions

What is the best-selling vitamin D on Amazon?

When we checked Amazon.com on October 31, 2026, Sports Research Vegan D3 + K2 was in the top 5 of Amazon's vitamins best sellers. Rankings change often, so choose by dose and testing rather than rank.

Is 5,000 IU of vitamin D too much?

It's above the 4,000 IU daily upper limit for adults, so it's best taken only with your doctor's guidance and a vitamin D blood test. Taking high doses long term without monitoring can raise calcium levels. For most people, 1,000–2,000 IU is a more common daily dose.

Which vitamin D on Amazon is best for women?

The same D3 products work for women and men; the right dose depends on your blood level, sun exposure and diet, not your sex. If you're pregnant or breastfeeding, ask your doctor which dose suits you.

Is there a vegan vitamin D3 on Amazon?

Yes. Most D3 comes from lanolin (sheep's wool), but Sports Research's D3 comes from lichen in a plant-based softgel. It also contains coconut, which matters if you have a coconut allergy.

Sources