Vitamin D3 + K2
Whether the K2 is worth paying for is a judgment rather than a computation, so it sits in Notes rather than on this page.
Pick your strength first. Within each strength the cheapest is listed first, priced per 1,000 IU so different bottles compare fairly. Stronger softgels usually cost far less per IU at about the same bottle price, which is why we never compare across strengths.
1,000 IU per serving
1 product| Brand | Per 1,000 IU | Bottle | Verification |
|---|---|---|---|
| Thorne 600 servings C · Claimed | 5.67¢ delivered | $34.00 | C · Claimed |
2,000 IU per serving
2 products| Brand | Per 1,000 IU | Bottle | Verification |
|---|---|---|---|
| BulkSupplements.com 365 softgels · cheapest here D · None located | 3.15¢ + delivery | $22.97 | D · None located |
| Core Med Science 60 capsules A · Certified | 14.2¢ + delivery | $16.99 | A · Certified |
2,500 IU per serving
1 product| Brand | Per 1,000 IU | Bottle | Verification |
|---|---|---|---|
| Sports Research 60 softgels D · None located | 18.3¢ delivered | $19.95 | D · None located |
5,000 IU per serving
7 products| Brand | Per 1,000 IU | Bottle | Verification |
|---|---|---|---|
| BulkSupplements.com 365 softgels · cheapest here D · None located | 1.26¢ + delivery | $22.97 | D · None located |
| Nutricost 120 softgels D · None located | 2.83¢ + delivery | $16.97 | D · None located |
| Evogen Nutrition 60 softgels D · None located | 6.65¢ + delivery | $19.95 | D · None located |
| EVLution Nutrition 60 capsules D · None located | 6.66¢ + delivery | $19.99 | D · None located |
| Sports Research 120 softgels D · None located | 8.57¢ delivered | $43.95 | D · None located |
| Sports Research 60 softgels D · None located | 10.5¢ delivered | $23.95 | D · None located |
| Sports Research 30 softgels D · None located | 16.3¢ delivered | $16.95 | D · None located |
10,000 IU per serving
4 products| Brand | Per 1,000 IU | Bottle | Verification |
|---|---|---|---|
| BulkSupplements.com 360 softgels · cheapest here D · None located | 0.72¢ + delivery | $25.97 | D · None located |
| Micro Ingredients 300 softgels D · None located | 1.17¢ + delivery | $34.95 | D · None located |
| Micro Ingredients 180 softgels D · None located | 1.39¢ + delivery | $24.95 | D · None located |
| Sports Research 60 softgels D · None located | 6.08¢ delivered | $28.95 | D · None located |
50,000 IU per serving
2 productsNot a daily dose. Products at these strengths are sold to be taken weekly or monthly, so there is no pick here. The per-unit price is shown and the comparison stops there.
| Brand | Per 1,000 IU | Bottle | Verification |
|---|---|---|---|
| BulkSupplements.com 365 softgels D · None located | 0.16¢ + delivery | $28.97 | D · None located |
| Micro Ingredients 240 softgels D · None located | Unknown + delivery | Unknown | D · None located |
Common questions
Which vitamin D3 brands are third-party tested?
Every vitamin D3 and D3 + K2 we track, grouped by whether a certifier lists the exact bottle, another size, or nothing we found. Absence is not a verdict.
Vitamin D3 1,000 IU vs 5,000 IU: which costs less?
What each strength costs per 1,000 IU, read from the labels and the prices we hold. A price comparison only: we do not say which strength anyone should take.
How much more does vitamin D3 with K2 cost?
Some brands sell the same softgel with and without K2, so the price of the K2 can be read from the labels. Compared at the same strength, from the panels.
Is BulkSupplements vitamin D3 NSF certified?
Which BulkSupplements D3 softgels NSF Certified for Sport names, at which bottle sizes, and which it does not, with the listing IDs.
Is Momentous vitamin D3 NSF certified?
Which Momentous vitamin D3 bottles we price NSF Certified for Sport names at the exact package. The listing IDs, the strengths and what each covers.
Do third-party tested supplements cost more?
The cheapest product we track in each category beside the cheapest one a certifier names at the exact package, where one exists, and the gap per dose.
Is BulkSupplements third party tested?
Every BulkSupplements product we track, by whether a certifier names the exact package sold, only another size, or nothing we found. With listing IDs.
Is Thorne vitamin D NSF certified?
Thorne D-1,000, D-5,000, D-10,000 and the liquids checked against NSF Certified for Sport: which bottles a listing names, with the listing IDs.
What is the cheapest NSF certified vitamin D3?
Every vitamin D3 and D3 + K2 we track whose exact bottle NSF names in its Certified for Sport database, compared on cost per 1,000 IU within each strength.
Is Thorne third party tested?
Every Thorne product we price, checked in NSF’s Certified for Sport database: which listing names the exact package sold, with the listing IDs.
Is Core Med Science third party tested?
Every Core Med Science product we price, checked in NSF’s Certified for Sport database: which listing names the exact package sold, and the IDs.
Is Optimum Nutrition third party tested?
Every Optimum Nutrition product we track, checked in the certifier databases: what each listing covers, package by package, with the listing IDs.
Is Momentous third party tested?
Every Momentous product we price, checked in NSF’s Certified for Sport database: where a listing names the exact package, and where it names another size.
Is BPN third party tested?
Every Bare Performance Nutrition product we price, checked in NSF’s Certified for Sport database: which package each listing names, and which it does not.
Which supplements are NSF Certified for Sport?
Every package we price that NSF names in its Certified for Sport database, by category, with the listing IDs and what each listing actually covers.
Do supplement prices actually change?
We re-read every price we can read automatically each day and keep every reading. Which prices have moved since we started, which have not, and by how much.
How many capsules is one serving?
How many pills the label calls one serving, across every capsule, tablet and softgel we price, and what that does to the count on the front of the bottle.
Is a vitamin D3 label in mcg the same as one in IU?
Convert vitamin D3 mcg to IU and back, checked against every label we price: one mcg is 40 IU, so 25 mcg is 1,000 IU and 125 mcg is 5,000 IU.
Is BUBS Naturals third party tested?
Every BUBS Naturals product we price, checked in NSF’s Certified for Sport database: which listing names the exact package sold, with the listing IDs.
Is Sports Research third party tested?
Every Sports Research product we track, checked in the certifier databases: which program lists each one, and which no database we searched lists.
Is Nature Made third party tested?
Every Nature Made product we price, checked against USP’s Verified Products directory and its own label: which packages carry both, product by product.
Is Nature Made vitamin D3 USP Verified?
Nature Made vitamin D3, every strength and count we price, checked against USP’s Verified directory and the USP Verified Mark on each bottle’s label.
About these numbers
What “per dose” means here: 1,000 IU vitamin D3
1,000 IU (25 mcg) sits just above the adult RDA of 600 IU (800 IU over 70) and well below the tolerable upper intake level of 4,000 IU/day, so it works as a shared unit across products sold from 1,000 IU to 50,000 IU per serving. Signed off by Dan on September 9, 2026 as the category's yardstick. It is a round number chosen for price comparison, not a recommended intake.
Compared in IU. 1 mcg = 40 IU; labels use both.
Source: NIH Office of Dietary Supplements, Vitamin D - Health Professional Fact Sheet · checked Aug 25, 2026 · verified by Dan
Where the data comes from
Every claim links to its source. Products, prices and certification listings are read from the retailers' own stores and the certifiers' own databases, and each figure links to the record it came from, so you can check any of them.
- Where a label does not state servings per container, the figure is derived from net weight and the product page says so.
- Amazon and Walmart are not included, so “cheapest” means cheapest among the retailers we track.
- Prices go stale. Each one shows when it was last checked, and says so when it is older than the retailer allows us to cache it.
- iHerb prices cannot be refreshed automatically. iHerb has not given us access to its price data, so those prices are marked stale until they are re-read. Each retailer offer carries its own check date.
Found something wrong? Tell us. Corrections are the point.
How we make money
No Buy button on this page earns us anything. The only links on the site that can are the Amazon links shown below the price comparison on some product pages, outside the comparison, and each says so beside it.
Commission will play no part in what we list, how it ranks, or which link we send you to. The Buy button points at the lowest price we have recorded even when that retailer pays us nothing.