NutriStack
Iron and Strontium, timing-sensitive.
Taking strontium and an oral iron supplement at the same time can lower how much of each you actually absorb. This mirrors the well-documented requirement to separate strontium from calcium: regulatory product information for strontium ranelate explicitly groups oral iron with calcium and food as agents that should be dosed several hours apart from strontium because they impair its uptake. The interaction is purely about co-administration timing, not a systemic or toxic effect, and it is fully avoidable by spacing the doses.
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At a glance
- Pair type
- Timing Sensitive
- Evidence (highest tier)
- Moderate
- Source citations
- 3 sources
- Stack Score effect
- −5 to your Stack Score (per scored timing-sensitive row).
- Scope
- Supplement × Supplement
- Last verified
- May 30, 2026
Timing Sensitive · Moderate evidence
Timing Sensitive
What is happening. Taking strontium and an oral iron supplement at the same time can lower how much of each you actually absorb. This mirrors the well-documented requirement to separate strontium from calcium: regulatory product information for strontium ranelate explicitly groups oral iron with calcium and food as agents that should be dosed several hours apart from strontium because they impair its uptake. The interaction is purely about co-administration timing, not a systemic or toxic effect, and it is fully avoidable by spacing the doses.
Mechanism. Strontium and iron are both polyvalent cations that compete for and chelate within the upper gastrointestinal tract. Strontium is absorbed largely by calcium-handling routes (paracellular transport and TRPV6/active calcium pathways), and co-ingested oral iron salts plus organic carriers such as ranelate or citrate can form poorly soluble complexes that blunt strontium uptake. Conversely, the divalent strontium cation can interfere with the acidic, transporter-mediated absorption of ferrous iron. The net effect is reduced bioavailability of one or both minerals when they share the same gastric window.
Recommendation. Separate strontium and oral iron by at least 2 hours (3 to 4 hours is ideal). A practical pattern: take iron with vitamin C earlier in the day on a relatively empty stomach, and take strontium at bedtime, at least 2 hours after the last food or mineral dose. Do not combine them in the same glass or the same with-meal slot.
Minimum separation. 2 hours (3 to 4 hours preferred)
Sources (3)
- European Medicines Agency, Protelos (strontium ranelate) Summary of Product Characteristics, section on interactions with food, calcium and oral iron.
- Lipworth and colleagues, Absorption of strontium from the gastrointestinal tract into plasma in healthy human adults, demonstrating food and cation effects on strontium bioavailability.
- General pharmacology and divalent-cation absorption reviews describing competitive uptake and chelation among polyvalent mineral cations in the gut.
Stack Score
How this pair moves the number.
Effect on the composite score
If both Iron 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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