What Is Os-Cal 500 With D? Uses, Dosage, and What You Need to Know in 2026

Os-Cal 500 With D is one of the best-known calcium supplements in the United States. If your doctor recently recommended it — or you're considering it for bone health — this guide covers everything you need to know: what it is, what it's used for, how to take it correctly, and what to watch out for.

What Is Os-Cal 500 With D?

Os-Cal 500 With D is a brand-name over-the-counter dietary supplement that combines two key nutrients for bone health:

• Calcium carbonate 500 mg: The active calcium compound. Calcium carbonate is 40% elemental calcium, so each 500 mg tablet delivers approximately 200 mg of usable calcium to the body.
• Cholecalciferol (Vitamin D3): The "D" in Os-Cal 500 With D. Vitamin D3 is the most biologically active form of Vitamin D and is essential for calcium absorption in the gut. The dose varies by formulation: some versions provide 200 IU, others 600 IU.

Os-Cal 500 With D is manufactured by Haleon, the consumer healthcare company spun off from GlaxoSmithKline in 2022. It is available OTC in tablet and chewable forms at most major pharmacy chains and online retailers.

What Is Os-Cal 500 With D Used For?

Os-Cal 500 With D is most commonly used for:

• Osteoporosis prevention and treatment: Adequate calcium and Vitamin D are essential components of any osteoporosis management plan. Os-Cal 500 With D helps ensure patients meet daily intake goals when diet alone is insufficient.
• Hypocalcemia (low blood calcium): Used to treat or prevent low calcium levels caused by dietary deficiency, malabsorption, or medical conditions that reduce calcium availability.
• Bone health maintenance: Many adults — particularly postmenopausal women, older men, and those with limited dairy intake — don't consume enough calcium from food alone. Os-Cal 500 With D helps fill that gap.
• Adjunct to osteoporosis medications: All major clinical trials of bisphosphonates (like alendronate/Fosamax), denosumab (Prolia), and other osteoporosis drugs required patients to also take calcium and Vitamin D supplements. Os-Cal 500 With D is often used alongside these prescription treatments.
• Vitamin D deficiency supplementation: Studies show that Vitamin D deficiency is common in the U.S., especially in northern climates and among people who get little sun exposure. Os-Cal 500 With D addresses both calcium and Vitamin D needs in one product.

How to Take Os-Cal 500 With D: Dosage Instructions

Here is what you need to know about taking Os-Cal 500 With D correctly:

• Take with food: Calcium carbonate requires stomach acid to dissolve and absorb properly. Taking it with meals increases stomach acid production and significantly improves absorption.
• Typical adult dose: 1–2 tablets twice daily, as directed by your healthcare provider. Follow product labeling or your doctor's instructions.
• Split your dose: Your body can only absorb approximately 500 mg of calcium at a time. If your total daily dose is more than 500 mg from supplements, take it in divided doses — for example, one tablet with breakfast and one with dinner.
• Don't exceed 2,000–2,500 mg total daily calcium: This upper limit includes calcium from all food sources plus supplements. More is not better.
• Separate from certain medications: Take Os-Cal 500 With D at least 30 minutes after bisphosphonates, 2+ hours away from quinolone or tetracycline antibiotics, and 4+ hours away from levothyroxine.

Who Should NOT Take Os-Cal 500 With D?

Tell your doctor before starting Os-Cal 500 With D if you have:

• Hypercalcemia (high blood calcium)
• Hypervitaminosis D (too much Vitamin D)
• A history of kidney stones (especially calcium oxalate stones)
• Hypophosphatemia (low blood phosphate)
• Sarcoidosis or other granulomatous diseases

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Os-Cal 500 With D During Pregnancy and Breastfeeding

Calcium and Vitamin D are important during pregnancy and breastfeeding. Os-Cal 500 With D is generally considered safe during pregnancy at recommended doses — controlled studies in pregnant women have shown no evidence of fetal risk at normal supplement doses. Always inform your OB-GYN about all supplements you're taking to avoid exceeding safe total daily calcium and Vitamin D limits.

Where to Find Os-Cal 500 With D

Os-Cal 500 With D is available at most major pharmacies, grocery stores, and online. If you're having trouble finding it at your local pharmacy, medfinder can locate which pharmacies near you have it in stock by calling them on your behalf — results delivered by text.

Curious about exactly how Os-Cal 500 With D works in your body? See our in-depth explanation of the mechanism of action of Os-Cal 500 With D.