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 Os-Cal® Chewable Os-Cal® Extra + D3
    Source of Calcium Refined calcium carbonate Refined calcium carbonate Refined calcium carbonate Refined calcium carbonate
    Amount of calcium carbonate per caplet 1500 mg 1250 mg 1250 mg 1250 mg
    Amount of element calcium per caplet 600 mg
    500 mg 500 mg 500 mg
    Vitamin D 500 IU 200 IU 600 IU 600 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.