Magnesium upper limit: how much is too much per day?
For adults 19 and older, the upper limit (UL) of magnesium is 350 mg per day, counting magnesium from supplements and medications only.
Every life stage
| Group | Age | RDA or AI mg/day | UL mg/day |
|---|---|---|---|
| Male | 14–18 | 410 RDA | 350 |
| Male | 19–30 | 400 RDA | 350 |
| Male | 31–50 | 420 RDA | 350 |
| Male | 51–70 | 420 RDA | 350 |
| Male | 71+ | 420 RDA | 350 |
| Female | 14–18 | 360 RDA | 350 |
| Female | 19–30 | 310 RDA | 350 |
| Female | 31–50 | 320 RDA | 350 |
| Female | 51–70 | 320 RDA | 350 |
| Female | 71+ | 320 RDA | 350 |
| Pregnancy | 14–18 | 400 RDA | 350 |
| Pregnancy | 19–30 | 350 RDA | 350 |
| Pregnancy | 31–50 | 360 RDA | 350 |
| Lactation | 14–18 | 360 RDA | 350 |
| Lactation | 19–30 | 310 RDA | 350 |
| Lactation | 31–50 | 320 RDA | 350 |
RDA = Recommended Dietary Allowance; AI = Adequate Intake, used where there is not enough data for an RDA. UL = Tolerable Upper Intake Level. “Not set” means the tables give no value. Ages under 14 are in the National Academies tables and are not covered here.
What counts toward the limit
This UL covers magnesium from supplements and medications only. Magnesium in food and water does not count toward it.
That is why the adult RDA (310–420 mg) can be higher than the UL (350 mg): the RDA is about total intake including food, while the UL is about supplements only.
Table footnote, as recorded in Ceiling’s data: “UL applies to magnesium from supplements and medications only, not from food and water.”
How Ceiling uses this
Ceiling adds up every supplement you scan and compares your daily total with this number. This UL counts supplements only, which is also what Ceiling adds up. Ceiling is coming soon on iPhone. No account; everything stays on your iPhone.
What is the upper limit of magnesium?
For adults 19 and older, the upper limit (UL) of magnesium is 350 mg per day, counting magnesium from supplements and medications only.
Sources
- Food and Nutrition Board, National Academies of Sciences, Engineering, and Medicine. Dietary Reference Intakes (DRIs): Summary tables (Appendix J), in Dietary Reference Intakes for Sodium and Potassium (2019), Appendix J. NCBI Bookshelf NBK545442, tables J-2, J-3, J-8 and J-9. https://www.ncbi.nlm.nih.gov/books/NBK545442/
- NIH Office of Dietary Supplements, Magnesium fact sheet for health professionals.
- Ceiling reference data built 2026-10-03 from the tables above.
General information, not medical advice. Talk to a clinician about your own situation.