Skip to content

Coming soon. The store is not open yet.

Menu
Full Measure

Medicines and supplements

Supplements to avoid with bisphosphonates

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

Ask your pharmacist or doctor before combining. Drug labels and NIH document 2 supplements for bisphosphonates such as alendronate: calcium and magnesium. Both can interfere with absorption of the medicine, and the alendronate label tells people to wait after the dose before taking anything else by mouth. Your pharmacist can set the timing for your own products.1,2,3

Key facts

  • MedlinePlus describes alendronate as a bisphosphonate used for osteoporosis and Paget's disease of bone, taken on an empty stomach with plain water.3
  • The alendronate label says calcium supplements, antacids and other oral medicines containing multivalent minerals interfere with its absorption.1
  • NIH's magnesium fact sheet says magnesium may interact with oral bisphosphonates.2
  • MedlinePlus names calcium supplements and antacids, such as calcium carbonate and milk of magnesia, among products that may interact with alendronate.3
  • Both entries are on the label and carry the severity separate doses.1,4

What do bisphosphonates do, and why do mineral supplements matter?

Bisphosphonates are a class of medicines, and alendronate is the example MedlinePlus describes. It is used for osteoporosis and Paget's disease of bone, conditions in which bones become thin, weak or deformed, and it works by slowing bone breakdown. The page says to take it just after getting up, on an empty stomach, with plain water, and to wait before eating, drinking or taking any other medicine, including vitamins or antacids.3

That routine is where the supplement question begins. The label groups calcium supplements, antacids and other oral products that contain multivalent minerals together as things that interfere with absorption of the medicine.1

Does calcium interfere with bisphosphonates?

Ask your pharmacist how far apart to take them

Calcium supplements and antacids interfere with the absorption of bisphosphonates such as alendronate. The alendronate label tells patients to wait after their dose before taking any other medicine by mouth.1

On the medicine's label

Two details from MedlinePlus keep this from being a simple avoid-calcium message. Its page lists calcium supplements among products that may interact, yet its dietary instructions for alendronate also mention foods and drinks rich in calcium and vitamin D. Read together, the sources describe a spacing question for supplements, and your pharmacist is the person to set the spacing for yours.3

Does magnesium interfere with bisphosphonates?

Ask your pharmacist how far apart to take them

Supplements and medicines rich in magnesium can reduce the absorption of oral bisphosphonates such as alendronate. The alendronate label says calcium, antacids and oral medicines containing minerals such as magnesium interfere with its absorption.2,4,5

On the medicine's label

The magnesium card is cited to NIH's fact sheets and to the alendronate label. Magnesium turns up in places people do not think of as supplements: NIH lists multivitamin and mineral supplements, laxatives and products for heartburn and indigestion, and MedlinePlus names milk of magnesia among the antacids that may interact.3,5

Does this apply to every bisphosphonate?

The label wording on this page is for alendronate, and NIH's magnesium sheet refers to oral bisphosphonates as a group. For any other bisphosphonate, the sources on this page do not address it. That is not a finding either way, so ask your pharmacist.1,2

What do separate doses and on the label mean here?

Both cards carry the same tags: the severity separate doses and the basis on the label. Separate doses is the page's plain-word way of saying the sources describe a spacing problem. This page gives no spacing, because the MedlinePlus page describes a strict morning routine for alendronate, and where a supplement fits into that routine depends on the product and on your schedule.3

What to ask your pharmacist about bisphosphonates and supplements

  • Which bisphosphonate am I taking, and what is the exact routine for it?
  • Where do my calcium and magnesium products fit in my day around the dose?
  • Do my antacids, multivitamin or protein powder contain calcium or magnesium?1
  • Should my doctor know my blood calcium or vitamin D level?3

Questions people ask

What supplements should I avoid with bisphosphonates?

Official sources document calcium and magnesium supplements, and both are tagged separate doses on the label. The sources describe a spacing problem, not a reason to drop them, so ask your pharmacist how to fit them around the dose.1,4

Which vitamins should not be taken with bisphosphonates?

Vitamin D is not named in the interaction entries here. MedlinePlus mentions it twice on its alendronate page: in the dietary instructions, and in asking you to tell your doctor about a low level. Products that contain calcium or magnesium are the ones the sources link to absorption problems.1,3

Which supplements interact with bisphosphonates?

The 2 documented are calcium and magnesium. The alendronate label says calcium supplements, antacids and other oral medicines with multivalent minerals interfere with absorption, and NIH says magnesium may interact with oral bisphosphonates.1,2

Do antacids matter with bisphosphonates?

The alendronate label groups antacids with calcium supplements as products that interfere with absorption, and MedlinePlus names calcium carbonate and milk of magnesia among them. Ask your pharmacist about the antacid you use.1,3

See what we make

Every product shows its whole label and what its lab report covers. The store opens soon.

See the Full Measure line

Sources

  1. Alendronate sodium tablets: prescribing information (Northstar Rx). DailyMed, U.S. National Library of Medicine. Effective June 12, 2026. Opened 2026-10-07.
  2. National Institutes of Health, Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals. Updated January 6, 2026. Opened 2026-10-06.
  3. MedlinePlus. Alendronate. U.S. National Library of Medicine. Last revised May 15, 2026. Opened 2026-10-11.
  4. Fosamax (alendronate sodium) tablets: prescribing information (Organon). DailyMed, U.S. National Library of Medicine. Label effective March 12, 2026. Opened 2026-10-07.
  5. Office of Dietary Supplements, National Institutes of Health. Magnesium: Fact Sheet for Consumers. Updated March 22, 2021. Opened 2026-10-06.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.