NutriStack
Alendronate and Strontium, timing-sensitive.
Strontium is a divalent cation that can chelate bisphosphonates in the gut, blocking absorption. Strontium and bisphosphonates also compete for incorporation into bone and have overlapping mechanisms, so combined use is generally avoided or strictly sequenced.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Alendronate and Strontium
- Pair type
- Timing Sensitive
- Evidence (highest tier)
- Moderate
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored timing-sensitive row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Timing Sensitive · Moderate evidence
Timing Sensitive
What is happening. Strontium is a divalent cation that can chelate bisphosphonates in the gut, blocking absorption. Strontium and bisphosphonates also compete for incorporation into bone and have overlapping mechanisms, so combined use is generally avoided or strictly sequenced.
Mechanism. Sr2+ binds the phosphonate groups of alendronate to form insoluble complexes in the gut. In bone, strontium substitutes for calcium in hydroxyapatite and overlaps with bisphosphonate's effects on bone turnover.
Recommendation. Do not take strontium and alendronate at the same time. If both are used (rare in current practice), separate doses by at least 2 hours, and discuss with your prescriber whether the combination is truly indicated.
Minimum separation. 120
Sources (2)
- Wiesner A, Szuta M, Galanty A, Paśko P. Optimal Dosing Regimen of Osteoporosis Drugs in Relation to Food Intake as the Key for the Enhancement of the Treatment Effectiveness-A Concise Literature Review. Foods. 2021;10(4):720. PMID 33805435
- Kim JS, Jang SW, Son M, Kim BM, Kang MJ. Enteric-coated tablet of risedronate sodium in combination with phytic acid, a natural chelating agent, for improved oral bioavailability. Eur J Pharm Sci. 2016;82:36-42. PMID 26594027
Stack Score
How this pair moves the number.
Effect on the composite score
If both Alendronate and Strontium are in the same stack, this pair applies −5 to your Stack Score (per scored timing-sensitive row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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