Calcium
What’s New This Month
- Fractures: A large 2026 review of 69 trials found little to no fracture benefit for people living at home, from calcium alone or with vitamin D. 1
- Heart: In a 2026 Hong Kong study of people who already had heart disease, those taking calcium alone had 21% more repeat heart events; calcium with vitamin D showed no excess. The study was observational. 2
- Antacid recall: In June 2026 FDA recorded a recall of 23 calcium carbonate antacid chewables, including Tums and Kirkland Signature, for small metal particles; all 23 are still open. These are antacids, not calcium supplements, but they share the same active ingredient. 3
- Lead: Four California notices since October 2024 allege lead in calcium supplements; none has been filed since 18 September 2026. Notices are allegations, not lab findings. 4
Overview
Calcium is the most common mineral in the body, and almost all of it is in bones and teeth. Adults need 1,000 to 1,200 mg a day, mostly from dairy, greens and fortified foods. 5
People have used lime and other calcium compounds in building for thousands of years. Humphry Davy first isolated calcium metal in 1808. 6
Most supplements are calcium carbonate or citrate. Labels claim stronger bones, fewer fractures, healthy teeth, and heart, muscle and nerve support.
How We Researched It
We rate each marketing claim with a modified version of GRADE, the system medical researchers use to say how sure we can be (i.e., high, moderate, low or very low), and check each trial with the Cochrane risk-of-bias tool, which asks whether a study’s design could skew its results. For calcium we appraised 26 records, published mostly from October 2022 to October 2026, plus older landmark trials. We also checked 10 regulators and safety databases, and used four Cochrane reviews.
Research NotesTop three benefits
Bone Density GRADE: Moderate
Across 59 trials, bone density rose 0.7 to 1.8% at the hip, spine and forearm. The gain came in the first year, then leveled off. 8 In a trial of 36,282 women, hip density rose about 1%. 22 Both gains are below the 3% change we treat as meaningful.
Bias check: Gains this small have not been shown to lower fractures. Calcium from food gave the same gain as pills. 8
Fracture Prevention GRADE: Moderate
A 2026 review of 69 trials found calcium alone (relative risk 0.91, range 0.81 to 1.01) and calcium with vitamin D (0.91, range 0.84 to 0.99) had little to no effect against the size of benefit set in advance. 1 A 2025 review of calcium with vitamin D agreed. 23
Bias check: The review had no funding; some authors report past payments for education work, one from a drug maker. 1
Heart Health GRADE: Low
Pooled trials found about 15% more heart disease with calcium pills. 10 In a Hong Kong study of people who already had heart disease, calcium alone was linked to 21% more repeat heart events, but calcium with vitamin D was not. 2
Bias check: Another pooled analysis found no clear rise. 24 The Hong Kong study was observational, so other factors may explain part of it.
Benefit Evaluation
| Claim | Claim Verdict | Research Confidence | Supporting Evidence | Safety Risk | Product Quality | FactStack™ Rating |
|---|---|---|---|---|---|---|
| Bone Density | Supported (small) | Moderate | Convincing | Caution | Variable | Favorable |
| Teeth | TBD | Very Low | TBD | Caution | Variable | Caution |
| Muscle and Nerve Function | TBD | Very Low | TBD | Caution | Variable | Caution |
| Colorectal Cancer Risk | TBD | Very Low | TBD | Caution | Variable | Caution |
| Bone Mass Under 35 | TBD | Low | TBD | Caution | Variable | Caution |
| Heart Health | Doubtful | Low | Doubtful | Caution | Variable | Warning |
| Fracture Prevention | Unsupported | Moderate | Unconvincing | Caution | Variable | Warning |
| Weight Management | Unsupported | Moderate | Unconvincing | Caution | Variable | Warning |
What Sellers Say vs. What Studies Show
| “Calcium pills stop broken bones.” | A large 2026 review found little to no fracture benefit for people living at home. The US task force does not advise low-dose calcium with vitamin D for this in women past menopause. 1 7 |
| “More calcium keeps building bone.” | Bone density rises about 1 to 2% in the first year, then stops. Calcium from food gives the same gain. 8 |
| “Calcium is good for your heart.” | Blood pressure fell about 1.4 points. Pooled trials link calcium pills to more heart events, not fewer. 9 10 |
| “Calcium helps you lose weight.” | Across 33 studies, weight changed by 0.01 kg. A 2024 Cochrane review in people with overweight found 0.15 kg, which is no real change. 11 12 |
| “Take all your calcium at once.” | The body absorbs less of a big dose: about 36% of 300 mg, but 28% of 1,000 mg. 5 |
| “Calcium pills build peak bone before 35.” | A review that mixed diets and pills found higher bone density, but a Cochrane review of pills alone in women aged 18 to 42 found little to no effect. 13 14 |
Trial ParametersIf you try it
| Who | Adults whose diet gives well under 1,000 to 1,200 mg a day, or who are told to take it with an osteoporosis drug. |
| Dose | Count food first and supplement only the gap, usually 500 mg or less per dose. 5 |
| Ceiling | Under 2,500 mg a day from food, supplements and antacids at ages 19 to 50; under 2,000 mg at 51 and older. 5 |
| Duration | No stop rule established. Bone gains level off after the first year. 8 |
| Form | Carbonate with meals; citrate with low stomach acid. Choose a USP- or NSF-verified product. Chewables and gummies carry choking and tooth-fracture reports. 15 |
| Ask First | Heart disease if taking calcium alone; kidney stones, parathyroid or kidney disease; pregnancy; thyroid pills, quinolones, dolutegravir, lithium or GLP-1 drugs. |
How to Take It
| Pick a plan | Add up the calcium in your food, then supplement only what is missing, in doses of 500 mg or less. 5 |
| Time of day | Not reported. Split larger amounts into two doses. 5 |
| With food | Take carbonate with meals. Citrate works with or without food. 5 |
| What to expect | You will not feel it. Bone density rises a little in the first year, then levels off. 8 |
| How to take | Carbonate is 40% calcium and citrate 21%, so check the label for the amount of calcium itself. Carbonate can cause gas or constipation. 5 |
Works With / Don’t Mix With
✓ Works with
Vitamin D. In the Hong Kong study, calcium taken with vitamin D showed no added heart risk, unlike calcium alone. 2
Food first. Calcium from dairy, greens and fortified foods raised bone density as much as pills did. 8
⚠ Ask first / don’t mix
Thyroid pills (levothyroxine). Calcium blocks their absorption; take them 4 hours apart. 5
Quinolone antibiotics and dolutegravir (an HIV drug). Take quinolones 2 hours apart; take dolutegravir 2 hours before or 6 hours after calcium. 5
Antacids and other calcium products. Many antacids are calcium carbonate; count them toward your daily limit. 5
Manufacturer Recalls & WarningsLast 36 months, newest first
| Date | Maker / Brand | Product | Action | Src |
|---|---|---|---|---|
| Sep 2026 | AlgaeCal; Adora; Wellness Resources; Earth’s Creation | Calcium supplements, incl. coral calcium and chocolate chews | Four California Prop 65 notices, Sep 2025 to Sep 2026, allege lead. Notices are allegations, not findings. | 4 |
| Jun 2026 | Guardian Drug Co. (Tums, Kirkland Signature, HyVee, H-E-B, CAREone and other store brands) | Calcium carbonate antacid chewables (antacids, not calcium supplements) | FDA Class II recalls D-0557-2026 to D-0579-2026 (23 products): small metal particles. All ongoing. | 3 |
| Mar 2025 | Mother Earth Minerals, Inc. (Ogden, UT) | Calcium, Magnesium and Silver liquid supplements | FDA warning letter: disease claims and no quality specifications for the calcium used; no response or closeout posted. A warning to one firm, not a recall. | 16 |
| Mar 2025 | Jamp (Canada) | Jamp Calcium Carbonate 500 + Vitamin D 1000 tablets | Health Canada recall RA-77092 (Type III): dissolution out of specification. | 17 |
| Feb 2025 | BIOV Health (Canada) | BIOV Health Calcium (Carbonate) 300 mg chewables | Health Canada recall RA-76925 (Type II): manufacturing-practice deficiencies. | 18 |
Where to Buy
We compare products side-by-side not just on price, but on whether NSF lists the product as NSF/ANSI 173 Contents Certified (an independent lab confirms the label matches the contents), whether it is NSF Certified for Sport, whether USP lists it as USP Verified, and whether the seller says it is manufactured in the USA. We leave out a brand’s products for this supplement when, in the last 36 months, the FDA took action against that brand over this supplement (a Class I or II recall, a warning letter, an import alert or an advisory letter). We also leave out any brand with an FDA Class II recall or warning letter on any product. We also leave out any product named in a California Prop 65 notice or a non-US recall, along with that brand’s products of the same ingredient and form. Brands with other actions stay listed and are marked in the Recall Screen column. Our goal remains to provide you, the Consumer, with the information and data necessary to make an informed purchasing decision. Prices reflected below are static and subject to change.
Ratings above describe the ingredient’s research, not any product listed below.
| # | Retailer | Product | Price | NSF 173 | NSF Sport | USP | Mfg. in USA (per seller) | Recall Screen | Affiliate link |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Amazon | Momentous Calcium, DimaCal, 250 mg per Serving | Check Price | ✓ | ✓ | ✓ | ✓ | View on Amazon ↗ | |
| 2 | Amazon | Nature Made Calcium 500 mg with Vitamin D3, 130 Tablets | Check Price | ✓ | ✓ | ✓ | View on Amazon ↗ | ||
| 3 | Amazon | THORNE Calcium, Chelated DiCalcium Malate, 120 Capsules | Check Price | ✓ | ✓ | ✓* | View on Amazon ↗ | ||
| 4 | Amazon | Theralogix TheraCal D2000 Bone Health, 360 Tablets | Check Price | ✓ | ✓ | ✓ | View on Amazon ↗ | ||
| 5 | HerbsPro | Source Naturals, Coral Calcium, Powder 4 Oz | $11.03 | ✓ | ✓ | View on HerbsPro ↗ | |||
| 6 | iHerb | NOW Foods, Calcium Hydroxyapatite Caps, 120 Capsules | $12.24 | ✓ | ✓* | View on iHerb ↗ | |||
| 7 | iHerb | Nature's Bounty, Calcium, 250 Tablets | $14.62 | ✓ | ✓ | View on iHerb ↗ | |||
| 8 | HerbsPro | Kal, Crystal Calcium, 10.6 oz | $18.99 | ✓ | ✓ | View on HerbsPro ↗ | |||
| 9 | Green's Nutrition | Solaray Calcium Citrate 240 Caps | $28.93 | ✓ | ✓* | View on Green's Nutrition ↗ | |||
| 10 | Green's Nutrition | Pure Encapsulations Calcium (Citrate) 180 Caps | $32.50 | ✓ | ✓* | View on Green's Nutrition ↗ |
Sources
1. Massé et al. Calcium and vitamin D for fracture prevention: meta-analysis of 69 trials. BMJ 393:e088050, 2026. doi.org/10.1136/bmj-2025-088050
2. Zhang X et al. Calcium supplements and repeat heart events in 237,782 Hong Kong adults with heart disease. Journal of the American Heart Association 15(8):e047455, 2026. pubmed.ncbi.nlm.nih.gov/41954050/
3. Class II recalls D-0557-2026 to D-0579-2026, Guardian Drug Co.: calcium carbonate antacid tablets (small metallic particles). US Food and Drug Administration (openFDA drug enforcement), 10 Jun 2026. api.fda.gov/drug/enforcement.json?search=recalling_firm:%22Guardian+Drug%22+AND+report_date:20260610&limit=30
4. Proposition 65 60-day notices for lead: 2026-04458 (AlgaeCal), 2026-02990 (Adora), 2026-01419 (Wellness Resources), 2025-03887 (Earth’s Creation). California Office of the Attorney General, Sep 2025 to Sep 2026. oag.ca.gov/prop65/60-Day-Notice-2026-04458
5. Calcium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements, updated 22 Jun 2026. ods.od.nih.gov/factsheets/Calcium-HealthProfessional/
6. Calcium: element information, properties and uses (History). Royal Society of Chemistry, Periodic Table, accessed 26 Sep 2026. periodic-table.rsc.org/element/20/calcium
7. US Preventive Services Task Force. Vitamin D, calcium or combined supplementation and fractures in adults living at home (recommendation). JAMA 319:1592, 2018. pubmed.ncbi.nlm.nih.gov/29677309/
8. Tai V et al. Calcium intake and bone mineral density: systematic review and meta-analysis (59 trials). BMJ 351:h4183, 2015. pubmed.ncbi.nlm.nih.gov/26420598/
9. Cormick G et al. Calcium supplementation for prevention of high blood pressure (Cochrane review). Cochrane Database of Systematic Reviews CD010037.pub4, 2022. pubmed.ncbi.nlm.nih.gov/35014026/
10. Myung SK et al. Calcium supplements and cardiovascular disease: meta-analysis of 13 trials. Nutrients 13(2):368, 2021. doi.org/10.3390/nu13020368
11. Li P et al. Calcium intake and body weight: meta-analysis of 33 studies (4,733 people). American Journal of Clinical Nutrition 104(5):1263, 2016. doi.org/10.3945/ajcn.116.136242
12. Cormick et al. Calcium supplementation for people with overweight or obesity (Cochrane review). Cochrane Database of Systematic Reviews CD012268.pub2, 2024. doi.org/10.1002/14651858.CD012268.pub2
13. Liu et al. Calcium intake and bone in people aged 35 or under: meta-analysis of 43 studies. eLife 11:e79002, 2022. doi.org/10.7554/eLife.79002
14. Méndez-Sánchez et al. Calcium and vitamin D for bone health in healthy premenopausal women (Cochrane review). Cochrane Database of Systematic Reviews CD012664.pub2, 2023. doi.org/10.1002/14651858.CD012664.pub2
15. CAERS adverse event reports, brand name “calcium”, 3 Oct 2024 to 3 Oct 2026 (101 reports). US Food and Drug Administration (openFDA food adverse events), data to 7 Jul 2026. api.fda.gov/food/event.json?search=products.name_brand:calcium+AND+date_created:[20241003+TO+20261003]&limit=100
16. Warning letter 692527, Mother Earth Minerals, Inc. (calcium, magnesium and silver liquids). US Food and Drug Administration, 28 Mar 2025. www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/mother-earth-minerals-inc-692527-03282025
17. Jamp Calcium Carbonate 500 + Vitamin D 1000 Tablet; Out of Specification (Dissolution), RA-77092. Health Canada, 11 Mar 2025. recalls-rappels.canada.ca/en/alert-recall/jamp-calcium-carbonate-500-vitamin-1000-tablet-out-specification-dissolution
18. BIOV Health Calcium (Carbonate) recall due to deficiencies in Good Manufacturing Practices, RA-76925. Health Canada, 6 Feb 2025. recalls-rappels.canada.ca/en/alert-recall/biov-health-calcium-carbonate-recall-due-deficiencies-good-manufacturing-practices-gmp
19. Close-out letter, Global Calcium House 1 (692000). US Food and Drug Administration, 30 Jul 2026. www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/global-calcium-house-1-692000-07302026
20. GRAS Notice Inventory (20 calcium notices; newest closed Jun 2024). US Food and Drug Administration, 3 Oct 2026. www.fda.gov/food/generally-recognized-safe-gras/gras-notice-inventory
21. NSF/ANSI 173 certified dietary supplements: trade name “calcium” (34 entries, 14 makers). NSF International, 3 Oct 2026. info.nsf.org/Certified/Dietary/
22. Jackson RD et al. Calcium plus vitamin D and the risk of fractures (Women’s Health Initiative). New England Journal of Medicine 354:669, 2006. doi.org/10.1056/NEJMoa055218
23. Cong & Zhang. Calcium with vitamin D in postmenopausal osteoporosis: meta-analysis of 11 trials. BMC Musculoskeletal Disorders 26:928, 2025. doi.org/10.1186/s12891-025-09089-7
24. Huo et al. Calcium supplements and heart attack or stroke: meta-analysis of 11 placebo-controlled trials. Current Developments in Nutrition 7(3):100046, 2023. doi.org/10.1016/j.cdnut.2023.100046
