Calcium
Calcium is a moderate-risk supplement with an RDA of 1000 mg and a tolerable upper intake level (UL) of 2500 mg per day according to NIH/NASEM standards. CNS lists a RDA of 800 mg and a UL of 2000 mg; MHLW lists a RDA of 700 mg with the same UL. It has 2 known interactions with other supplements including iron, zinc. Use NutriAudit to check if your supplement stack keeps this ingredient within safe limits.
Quick take
Calcium sits in the Major Minerals category. This page consolidates 5 regional standards, and the limits vary enough that you should not treat one region's rule as universal.
It also has 2 known interactions, so the question is not just the label dose but whether the rest of your stack adds extra risk.
Taking multiple supplements? Check Calcium for overlap
If Calcium appears on two product labels, enter each daily amount and check the combined label total.
Check Calcium across my supplementsFree. No account required.
Overdose Risk Warning
Very high calcium may increase kidney stone risk and interfere with absorption of other minerals.
Regional Reference Values
| Region | Organization | RDA | Upper Limit (UL) | Unit |
|---|---|---|---|---|
| 🇺🇸 United States | FDA | 1000 | 2500 | mg |
| 🇪🇺 Europe | EFSA | 1000 | 2500 | mg |
| 🇦🇺 Australia | NHMRC / Eat For Health | 1000 | 2500 | mg |
| 🇨🇳 China | 国家卫健委 WS/T 578.2—2018 | 800 | 2000 | mg |
| 🇯🇵 Japan | MHLW Dietary Reference Intakes 2025 | 700 | 2500 | mg |
RDA = Recommended Daily Allowance (adequate intake for most adults). UL = Tolerable Upper Intake Level; some authorities have not established one.
Known Interactions
Calcium may interfere with iron absorption when taken together.
Consider taking calcium and iron at different times of day, and ask a doctor or pharmacist for advice tailored to you.
High doses of calcium may reduce zinc absorption.
Consider taking at different times.
How to use this page
First match your product label against the dose table above, then check whether the known interaction list includes anything in your current stack.
If you are taking multiple supplements, the safest approach is usually to audit the whole stack instead of judging a single bottle in isolation.
Frequently Asked Questions
How much Calcium is too much?
FDA lists a formal upper limit (UL) of 2500mg per day for Calcium. Other regions may use a different value or have no established UL.
What is the recommended daily dose of Calcium?
The RDA for Calcium is 1000mg per day for most adults. This amount is sufficient to meet the needs of 97-98% of healthy individuals.
Does Calcium interact with other supplements?
Yes, Calcium has 2 known interactions with other supplements. Calcium may interfere with iron absorption when taken together.
Are you taking Calcium?
Check if your supplement stack keeps Calcium within safe limits.
Audit My SupplementsDisclaimer: NutriAudit is a decision-support tool designed to help you review your supplement stack for potential duplicate, conflicting, or excessive ingredients. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making changes to your supplement routine, especially if you are pregnant, nursing, taking medications, or have a medical condition.
Uses cited public reference data where the current dataset has a verified entry.