Frequently Asked Questions

Common questions about Os-Cal®

  • When is the best time of day to take Os-Cal®?

    For optimal calcium absorption, take Os-Cal® supplements with meals.

  • How much Os-Cal® should I be taking?

    Please consult your physician about your individual calcium requirements and follow all Os-Cal® supplements label directions.

  • It’s difficult for me to swallow pills. Can I chew, crush, or cut Os-Cal® caplets?

    Os-Cal® supplement caplets are not designed to be chewed. Crushing or cutting the tablet is acceptable and will not impact the therapeutic value of Os-Cal® supplements.

  • Can men take Os-Cal®?

    Yes. We all need calcium and it can be difficult to get what you need from diet alone. Please consult your doctor about your individual calcium requirements.

  • Does Os-Cal® help with bone loss and osteoporosis?

    Os-Cal® supplements keep your bones strong and healthy, as adequate intake of calcium and Vitamin D is linked to the reduced risk of osteoporosis through the mechanism of slowing the rate of bone loss for post-menopausal women, elderly men and women, and for persons with a family history of osteoporosis.

  • Can I use Os-Cal® if I am allergic to shellfish?

    The source of calcium carbonate in Os-Cal® supplements is derived from oyster shells, which are washed, oven-dried, and milled prior to being added to Os-Cal®. Please consult your doctor to determine whether Os-Cal® is right for you.

  • Is Os-Cal® constipating?

    Calcium carbonate products have been linked to mild constipation. If you experience constipation with Os-Cal® supplements, it does not resolve, or worsens, please consult your physician.

  • Will Os-Cal® cause kidney stones?

    If you suffer from or are prone to kidney stones, please consult with your physician prior to taking Os-Cal® supplements.

  • What are the recommended daily intake levels of Calcium and Vitamin D?

    Please refer to the following chart for the recommended daily values of Calcium & Vitamin D:

    Life Stage Group
    Calcium Recommended Dietary Allowance (mg/day) Vitamin D Recommended Dietary Allowance (IU/day)
    1-3 years old 7,00 **
    4-8 years old 1,000 600
    9-13 years old 1,300 600
    14-18 years old 1,300 600
    19-30 years old 1,000 600
    31-50 years old 1,000 600
    51-70 years old 1,000 600
    51-70 year old females 1,200 600
    71+ years old 1,200 800
    14-18 years old, pregnant / lactating 1,300 600
    19-50 years old, pregnant / lactating 1,000 600

    **For infants, adequate intake is 400 IU/day for 0 to 6 months of age and 400 IU/day for 6 to 12 months of age.

  • What is the difference between Os-Cal® products?

      Os-Cal® Ultra Os-Cal® Calcium + D3
    Source of Calcium Refined calcium carbonate Refined calcium carbonate
    Amount of calcium carbonate per caplet 1500 mg 1250 mg
    Amount of element calcium per caplet 600 mg
    500 mg
    Vitamin D 500 IU 200 IU
  • How does calcium in calcium carbonate compare to the calcium in calcium phosphate?

    Calcium carbonate contains more elemental calcium, the amount of calcium your body uses, than calcium phosphate.

  • How long does it take Os-Cal® to take effect?

    According to the National Osteoporosis Foundation, changes in bone density should be compared to baseline 1-2 years after starting calcium supplement therapy.

    Source: National Osteoporosis Foundation –

  • What is the Vitamin D compound in Os-Cal® products and how is it beneficial?

    The Vitamin D compound in Os-Cal® supplements is Vitamin D3, also known as cholecalciferol. Vitamin D3 is what your skin makes when it’s exposed to sunlight and is the form of Vitamin D that your body uses most easily to promote calcium absorption to enable normal mineralization of bone and bone growth.*

  • Which Os-Cal® variety was used in the NIH Study?

    Os-Cal® Calcium + D3

*These statements have not been evaluated by FDA. These products are not intended to diagnose, treat, cure, or prevent any disease.