Vitamin D3 compared by strength
One product per strength: 1,000 IU, 2,000 IU, 5,000 IU, side by side on IU per serving and the price per 1,000 IU. A strength at or above the 4,000 IU adult upper limit is flagged against it.
Prices checked Oct 14, 2026 3 products Vitamin D3: the evidence
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Not a ranking and not a recommendation. Ask your pharmacist or clinician before adding vitamin D, especially above the RDA or with a prescription medicine.
By strength
Prices are one-time prices at the size shown. 1 mcg of vitamin D3 is 40 IU.
Vitamin D3 by strength
Checked Oct 14, 2026| Strength | Product | Against the upper limit | Testing | Per 1,000 IU | Source |
|---|---|---|---|---|---|
| 1,000 IU | Supersmart Vitamin D3 1,000 IU 25 mcg (1,000 IU) per serving; 150 servings. | Below the 4,000 IU upper limit | Not stated in our records | $0.113 per 1,000 IU$17.00 for 150 servings · checked Oct 11, 2026 | Read on us.supersmart.com (paid link, opens in new tab) Paid link |
| 2,000 IU | HerbsPro NOW Foods Vitamin D-3, 2000 IU, 30 Softgels 50 mcg (2,000 IU) per serving; 30 servings. | Below the 4,000 IU upper limit | Not stated in our records | $0.046 per 1,000 IU$2.78 for 30 servings · checked Oct 14, 2026 | Read on herbspro.com (paid link, opens in new tab) Paid link |
| 5,000 IU | Dr. Tobias Dr. Tobias Vitamin D-3 5,000 IU (90 capsules) 125 mcg (5,000 IU) per serving; 90 servings. | At or above the 4,000 IU adult upper limit | Not stated in our records | $0.040 per 1,000 IU$17.99 for 90 servings · checked Oct 14, 2026 | Read on drtobias.com (paid link, opens in new tab) Paid link |
How we chose
The rule
Applied to the vitamin D3 page's Where to buy rows- For each labelled strength, the plain vitamin D3 product with the lowest price per 1,000 IU. Blends (D3 with K2 or anything else) are left out, because their price also pays for another ingredient.
- Prices and label lines are the ones on our vitamin D3 page, with the date each was checked.
- Who pays us does not change which product the rule picks. A product link pays us only when the brand is an active partner, and then it says so.
Strength against the RDA and the upper limit
What the vitamin D3 page records
NIH and the trials it cites- Adult RDA: 600 IU (15 mcg) per day through age 70, including pregnancy and breastfeeding; 800 IU (20 mcg) over 70. Adult UL: 4,000 IU (100 mcg) per day.
- UL is lower for children (1,000–3,000 IU depending on age). The FNB noted toxicity is unlikely below 10,000 IU/day but that intakes under the UL might still have adverse effects over time.
- Doses studied in human trials ranged from 400 to 10,000 IU/day of vitamin D3 (10 to 250 mcg/day), for 8 weeks to a median of 5.3 years. Some trials gave weekly or monthly amounts instead, such as 20,000 IU once a week or 60,000 IU once a month in D-Health.
- A strength at or above 4,000 IU is flagged in the table: the upper limit is a ceiling, not a target.
These statements have not been evaluated by the FDA. These products are not intended to diagnose, treat, cure, or prevent any disease.
Questions
Common questions
Which vitamin D3 strength should I take?
This page does not say. It shows one product per strength so the price per 1,000 IU can be compared. The adult RDA is 600 IU a day (800 IU over 70), and the adult upper limit is 4,000 IU. A blood test and your clinician are how a dose is set; our vitamin D3 page grades what the trials found.
Is a 5,000 IU product above the upper limit?
Yes. 5,000 IU in one serving is at or above the 4,000 IU adult upper limit; the table flags it. The upper limit is the most a day that is unlikely to cause harm for most adults, not a target, and it is lower for children.
Why does the table say testing is not stated?
Our records for these products hold the label line and the price, not a third-party testing certificate. We do not print a certification we have not recorded.
Does Kymata earn money from these links?
When the brand is an active partner, yes: its link is marked and pays us a commission. Which product the rule picks does not change with who pays us.