Can You Take Magnesium and Calcium Together? (What to Know + Best Timing)

Dec 1, 2025

Many people take magnesium and calcium together — often in the same supplement.
But should they be combined? And does timing matter?

Short answer: they can interfere with each other when taken incorrectly, especially if you are also taking iron. Here’s the full breakdown, plus how timed formulas like TRINITY Multi-Nutrients avoid nutrient competition altogether.

🔍 Do Magnesium and Calcium Compete for Absorption?

Magnesium and calcium share overlapping absorption pathways in the gut.
When taken in high doses at the same time:

Calcium may reduce magnesium absorption
Magnesium may slow calcium uptake
Both can compete with iron if taken simultaneously
Large doses can cause digestive discomfort

This doesn’t mean you must avoid taking them in the same day — just that timing matters.

⏰ When to Take Magnesium vs. Calcium

✔ Magnesium — Best Taken at Night

Especially magnesium glycinate, which supports:

Relaxation
Deeper sleep
Muscle recovery
Nervous system balance

This is why TRINITY includes magnesium exclusively in the Night Formula.

✔ Calcium — Best Taken During the Day, With Food

Calcium absorbs best with:

A meal
Vitamin D3
Vitamin K2

This is why TRINITY includes calcium in the Day Formula, paired with D3 + K2.

See TRINITY’s Day + Night timing

✔ Can You Take Magnesium and Calcium Together?

Yes — but not at the same time.

For ideal absorption:

Take calcium earlier in the day
Take magnesium in the evening
Separate by at least 4–6 hours

TRINITY does this separation for you automatically.

❌ Avoid This Common Mistake

Many “all-in-one” multis add:

Calcium
Magnesium
Iron

…in the same capsule.

These minerals all compete — the worst possible combination for absorption.

TRINITY Multi-Nutrients avoids this by designing formulas around nutrient synergy rather than convenience.

🧠 Summary

Magnesium and calcium shouldn’t be taken together in large doses
Magnesium is best at night
Calcium is best during the day with food
Both interfere with iron if taken together
TRINITY separates them into Night (magnesium) and Day (calcium) formulas