Guide
How much magnesium glycinate is too much?
The US upper limit for supplemental magnesium is 350 mg a day, set at the dose where loose stools become more likely. Real toxicity is a different, much rarer picture, mostly tied to impaired kidney function.
For adults with normal kidney function, the number to know is 350 mg a day of magnesium from supplements — the US tolerable upper limit, set because loose stools become more likely above it. Electric Tiger Magnesium Glycinate provides 275 mg per serving, under that limit. Real magnesium toxicity is a separate, rarer picture, tied mainly to impaired kidney function.
The number regulators use
The Institute of Medicine's 1997 dietary reference intake report set a magnesium upper limit (UL) of 350 mg/day for adults, but only counting supplements — not the magnesium already in food. Diarrhea was the effect that showed up first as researchers raised the dose, so it became the limiting factor for where the ceiling was drawn.
What the diarrhea data actually shows
A 2023 review searched for every intervention study published between 1997 and 2022 that tested a single-ingredient magnesium product and reported diarrhea as an outcome. Of ten studies identified — five meta-analyses and five randomized trials, spanning 128 to 1,200 mg a day — seven found no significant difference in diarrhea between the magnesium group and the control group. A search of the FDA's adverse event database, limited to single-ingredient magnesium products, found only 40 attributable gastrointestinal cases, and only about a third of those mentioned diarrhea. The review's authors argue the 350 mg limit may be more conservative than the current evidence supports; the official number hasn't changed.
What that means in practice: loose stools at higher doses are common enough to be the reason the limit exists, but they are a mild, dose-related, and reversible effect — stop or reduce the dose and it resolves. That is a different thing from toxicity.
Where real toxicity happens
Magnesium is cleared from the body by the kidneys. In someone with normal kidney function, the kidneys excrete excess magnesium efficiently, which is part of why oral magnesium toxicity is rare in healthy adults even well above the supplemental limit. The picture changes when kidney function is impaired.
An observational study followed 746 adults with chronic kidney disease, mostly stages 3 and 4, for an average of 42.6 months. Higher blood magnesium levels (hypermagnesemia) were associated with a higher risk of cardiovascular events and a higher risk of death from any cause, a pattern that held up even after matching patients on other characteristics. A separate 2025 review of magnesium in chronic kidney disease reaches the same conclusion from a different angle: supplementing magnesium in advanced kidney disease needs careful monitoring, because impaired clearance makes it easier for magnesium to build up to levels the body can't compensate for.
If you have kidney disease, ask your doctor before taking any magnesium supplement — this isn't a dose question the general adult numbers above can answer for you.
Our label against the limit
| Amount | |
|---|---|
| Elemental magnesium per serving (3 capsules) | 275 mg |
| Servings per bottle | 30 |
| Supplemental upper limit (adults) | 350 mg/day |
| Headroom before the limit | 75 mg/day |
That headroom is there because a supplement isn't your only source of magnesium — food contributes too, and the 350 mg figure only counts what comes from a supplement bottle.
Questions people ask
Is 500 mg of magnesium glycinate too much?
If that's 500 mg of elemental magnesium from supplements in a day, it's above the 350 mg/day upper limit, and loose stools become more likely at that range. It is not automatically dangerous for someone with normal kidney function — the review above found several studies at higher doses reporting no significant diarrhea difference — but it's above the official ceiling, and there's no benefit shown for going over it.
Can you overdose on magnesium glycinate?
Serious magnesium toxicity from an oral supplement is uncommon in people with normal kidney function, because the kidneys clear the excess. It becomes a real risk mainly when kidney function is impaired and magnesium can't be cleared normally, which is why kidney disease changes this answer.
What happens if you take too much magnesium glycinate?
The most commonly reported effect at higher doses is loose stools or diarrhea, which is dose-related and resolves when you cut back. That's the effect the 350 mg limit was built around.
What are the signs of too much magnesium?
At supplement doses, loose stools and stomach upset are the signs most often reported. More serious signs of hypermagnesemia — such as unusual muscle weakness or an irregular heartbeat — are associated with impaired kidney clearance, not with normal supplement use in someone with healthy kidneys, and warrant medical attention.
Is 275 mg of magnesium glycinate too much?
No — that's our label's full serving, and it sits under both the 350 mg/day supplemental limit and the top end of the adult dietary RDA (420 mg/day from food and supplements combined).
Related reading
Sources
- Perspective: Call for Re-evaluation of the Tolerable Upper Intake Level for Magnesium Supplementation in Adults In 7 of 10 trials between 128 and 1,200 mg a day, magnesium caused no more diarrhea than the comparison.
- Impact of Serum Magnesium Levels on Kidney and Cardiovascular Prognosis and Mortality in CKD Patients In people with chronic kidney disease, higher blood magnesium levels were linked to more cardiovascular events and higher death rates, which is why magnesium supplements are used cautiously in kidney disease.
- Unraveling the Mechanisms of Magnesium Supplementation in Alleviating Chronic Kidney Disease Complications and Progression: Balancing Risks and Benefits This review says both too little and too much magnesium carry risk in chronic kidney disease, and specifically warns that supplementing needs careful monitoring in advanced kidney disease because of the risk of magnesium building up.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
