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21st Century 600+D3, Calcium & Vitamin D3 Supplement, 400 Tablets
21st Century 600+D3, Calcium & Vitamin D3 Supplement, 400 Tablets
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Regular price
$9.99 USD
Regular price
Sale price
$9.99 USD
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The full picture
Everything Vyvata knows about this product — the score, the evidence, the FAQ, and where else to find shopper reviews. No hidden data. Every vendor is scored on the same published rubric — no brand can pay for placement. Read the rubric →
58/100
Standard
Six-dimension breakdown
Evidence
65
Formulation
55
Manufacturing
58
Safety
62
Transparency
60
Sustainability
50
Why this scored 58/100
Calcium 600mg + vitamin D3 is a bone-health basic. 21st Century is a US mass-market budget brand — calcium form typically carbonate rather than citrate, which requires food for absorption and can worsen constipation. D3 dose (typically 400IU in these SKUs) is below Institute of Medicine current RDA of 600-800IU. Would move to Standard 65+ with calcium citrate form and D3 at 1000-2000IU.
Last scored: Full rubric →
Evidence & sources
The Vyvata score's Evidence dimension measures the quality of published RCT support for a product's active ingredients at the label dose. Our source hierarchy: double-blind RCTs in MEDLINE-indexed journals > single-blind RCTs > open-label trials > observational studies > mechanism papers > N=1 case studies (anecdotes). Predatory journals and manufacturer-authored studies without independent replication are weighted down.
Product-specific evidence citations for this item are embedded in the analysis text on the "Analysis" tab. For the full framework and evidence hierarchy, see the methodology page.
How to read the Evidence dimension
- 80–100: Multiple double-blind RCTs in indexed journals directly testing this product OR the exact ingredients at the exact dose.
- 60–79: Single double-blind RCT + supporting ingredient literature at the studied dose.
- 40–59: Open-label trials + ingredient literature; no product-specific double-blind evidence.
- 20–39: Ingredient literature only; no product-specific trials or trials in predatory venues.
- 0–19: No credible evidence base or unverifiable claims.
Frequently asked questions
Auto-generated from Vyvata's scoring data for this product. For general questions about the store (shipping, returns, wholesale), see the site FAQ.
What is 21st Century 600+D3, Calcium & Vitamin D3 Supplement, 400 Tablets?
21st Century 600+D3, Calcium & Vitamin D3 Supplement, 400 Tablets, categorized under Vitamins & foundational micronutrients in the Supplements vertical. It is scored on the Vyvata Scoring Framework — an independent 6-dimension rubric applied uniformly to every product Vyvata lists.
How does 21st Century 600+D3, Calcium & Vitamin D3 Supplement, 400 Tablets score on the Vyvata rubric?
58/100 overall — Standard tier (50–69 band). Per-dimension breakdown: Evidence 65, Safety 62, Transparency 60, Manufacturing 58, Formulation 55, Sustainability 50. Scored as of 2026-08-24.
Why did 21st Century 600+D3, Calcium & Vitamin D3 Supplement, 400 Tablets score in the Standard tier?
Calcium 600mg + vitamin D3 is a bone-health basic. 21st Century is a US mass-market budget brand — calcium form typically carbonate rather than citrate, which requires food for absorption and can worsen constipation. D3 dose (typically 400IU in these SKUs) is below Institute of Medicine current RDA of 600-800IU. Would move to Standard 65+ with calcium citrate form and D3 at 1000-2000IU.
What are the strongest and weakest aspects of this product?
Strongest: Evidence at 65/100 (quality of published RCT support for the active ingredients at the label dose) and Safety at 62/100 (adverse-event profile, interaction risk, and dose ceiling). Weakest: Formulation at 55/100 (dose adequacy, bioavailability form, and ingredient redundancy) and Sustainability at 50/100 (sourcing practices, packaging, and corporate practice). All six dimensions feed the overall Vyvata score; a weakness on any one dimension pulls the overall down proportionally.
Is 21st Century 600+D3, Calcium & Vitamin D3 Supplement, 400 Tablets third-party tested?
No third-party certifications (NSF, USP, ConsumerLab, or equivalent) were on record at the time of scoring. This affects the Manufacturing dimension score. The manufacturer may test internally or have obtained certification more recently — check the current product label for the most up-to-date information.
What would move 21st Century 600+D3, Calcium & Vitamin D3 Supplement, 400 Tablets to a higher tier?
Would move to Standard 65+ with calcium citrate form and D3 at 1000-2000IU.
Are there higher-scoring alternatives to 21st Century 600+D3, Calcium & Vitamin D3 Supplement, 400 Tablets?
The top-ranked vitamins & foundational micronutrients product in the Vyvata catalog is currently Thorne Basic Nutrients 2/Day at 89/100. See the full ranked list of 635 scored products in this subcategory at https://vyvata.com/pages/best-vitamins-and-foundational-micronutrients-supplements-ranked.
What does the Vyvata score mean?
The Vyvata Scoring Framework rates every listed product 0–100 across six dimensions: Evidence, Formulation, Manufacturing, Safety, Transparency, and Sustainability. Tier bands: Elite 85–100 (top-tier evidence + formulation + manufacturing), Verified 70–84 (strong on most dimensions), Standard 50–69 (solid but with weaknesses called out), Rejected 0–49 (specific failures documented). Rejected products remain listed with reasons. Full methodology at https://vyvata.com/pages/methodology.
Where can I read customer reviews for 21st Century 600+D3, Calcium & Vitamin D3 Supplement, 400 Tablets?
The Vyvata score measures product integrity against a published rubric, not customer sentiment. For customer reviews and community discussion, search external platforms directly: Amazon (https://www.amazon.com/s?k=21st%20Century%20600%2BD3%2C%20Calcium%20%26%20Vitamin%20D3%20Supplement%2C%20400%20Tablets),Google(https://www.google.com/search?q=21st%20Century%20600%2BD3%2C%20Calcium%20%26%20Vitamin%20D3%20Supplement%2C%20400%20Tablets+reviews),Reddit(https://www.reddit.com/search/?q=21st%20Century%20600%2BD3%2C%20Calcium%20%26%20Vitamin%20D3%20Supplement%2C%20400%20Tablets%20review),andTrustpilot(https://www.trustpilot.com/search?query=21st%20Century%20600%2BD3%2C%20Calcium%20%26%20Vitamin%20D3%20Supplement%2C%20400%20Tablets).Vyvatadoesnotaggregate,republish,orlicensethosethird-partyreviews.
Customer reviews
Reviews on other platforms
The Vyvata score measures product integrity against a published rubric, not customer sentiment. Vyvata does not aggregate, republish, or license third-party reviews — the links below open search pages on their respective platforms.
All the data we have on this product
Every VSF-related metafield surfaced verbatim. Nothing hidden. If you spot data that looks wrong, let us know.
- VSF score
- 58 / 100
- Tier
- Standard
- Category
- Supplements
- Subcategory
- vitamins micronutrients
- Last scored
- Third-party certifications
- None on record at time of scoring
- Vendor
- Pasteur Pharmacy
- Product type
- Vitamins & Supplements
- Tags
- Pasteur Pharmacy, Shopify Collective
Every score is set from the published rubric, audit-logged, and rescored whenever new evidence emerges (published trials, updated labels, third-party testing releases). Every vendor is scored on the same criteria — no pay-to-play. See our editorial-independence disclosure for the full policy, including brands with an editorial relationship to this site.
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