🟢 100/100

This product looks safe

  • No ingredients exceed tolerable upper intake levels
  • 50% of ingredients have research evidence
A Label Compliance Grade

Product Label

📸

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Label Data

2 Tablet(s) Serving Size
45 Servings
Single Vitamin and Mineral Product Type
50% Evidence Coverage

Supplement Facts — Evidence Check

250 IU (60% DV)
✅ Within RDA (0.4× RDA of 0.015 mg) 📚 604 studies (Tier A: 16, B: 251)
RDA 0.015mg This product: 0.00625mg UL 0.1mg
Calcium
500 mg (50% DV)

Other Ingredients

Croscarmellose Sodium Stearic Acid Cellulose Magnesium Stearate

Label Claims — Verification

Nutrient
All Other
Structure/Function
All Other (99% of products) Structure/Function (85% of products) Nutrient (54% of products) Approved Health (3% of products)

Target Groups

Adult (18 - 50 Years)

Product Information

📋 Directions for Use

Directions: Take up to (2) tablets daily with any meal for maximum daily results, or as directed by your healthcare provider. Do not exceed recommended dosage.

⚠️ Warnings & Precautions

Keep out of reach of children.

Do not use if product appears to be tampered with or seal is broken.

🧪 Formulation Notes

No added Sugar, Salt, Yeast, Preservatives or Artificial Flavors.

Contains a shellfish ingredient (oyster shell).

Oyster Shell Calcium 250 +D

Additional Information

MADE IN USA

0108

Regular exercise and a healthy diet with enough calcium helps those at high risk, including teen and young adult Caucasian and Asian women, maintain good bone health and reduce their high risk of developing osteoporosis later in life. Adequate calcium is important, but daily intakes of above about 2000mg are not likely to provide any additional benefit. Vitamin D is essential for use of calcium and necessary for healthy bones, teeth and cartilage.*

Store at room temperature.

Unconditionally guaranteed for purity, freshness and label potency.

20% FREE

D3

Product Details

UPC / SKU 7 40985 22302 4
DSLD Entry Date 2012-07-25
Product Type Single Vitamin and Mineral
Form Tablet or Pill
Brand 21st Century
DSLD ID 11094
Data Updated 2026-04-11

Research Evidence

849 Research Sources
56 Avg Quality Score
450 Meta Analysis
152 Rct
137 Systematic Review
73 Clinical Trial
11 Regulatory Source
7 Other
7 Guideline
3 Openfda Safety
2 Cochrane Review
2 Observational
A Phosphate binders for preventing and treating chronic kidney disease-mineral and bone disorder (CKD-MBD)
Meta Analysis The Cochrane database of systematic reviews 2018
A Calcium supplementation (other than for preventing or treating hypertension) for improving pregnancy and infant outcomes
Meta Analysis The Cochrane database of systematic reviews 2024
A Calcium supplementation (other than for preventing or treating hypertension) for improving pregnancy and infant outcomes
Meta Analysis The Cochrane database of systematic reviews 2015
A Vitamin and mineral supplementation for maintaining cognitive function in cognitively healthy people in mid and late life
Meta Analysis The Cochrane database of systematic reviews 2018
A Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems
Meta Analysis The Cochrane database of systematic reviews 2025
A Dietary calcium supplementation for preventing colorectal cancer and adenomatous polyps
Systematic Review The Cochrane database of systematic reviews 2008
A Calcium and vitamin D for increasing bone mineral density in premenopausal women
Systematic Review The Cochrane database of systematic reviews 2023
A Dietary sodium, sodium-to-potassium ratio, and risk of stroke: A systematic review and nonlinear dose-response meta-analysis
Meta Analysis Clinical nutrition (Edinburgh, Scotland) 2019
A The association between circulating magnesium and clinically relevant outcomes in patients with chronic kidney disease: A systematic review and meta-analysis
Meta Analysis Clinical nutrition (Edinburgh, Scotland) 2021
A Calcium channel blockers versus other classes of drugs for hypertension
Systematic Review The Cochrane database of systematic reviews 2021
View all evidence for Electrolytes →

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