Magnesium bisglycinate is one of the most popular forms of magnesium, and one of the most common questions about it is whether it has side effects. The short answer: at normal doses it is generally well tolerated, and the side effects people do notice are usually mild and digestive. This guide covers what to expect, how much is too much, and who should check with a doctor before taking it.

What is magnesium bisglycinate?

Magnesium bisglycinate is magnesium bound to two molecules of the amino acid glycine. This bound form is called a chelate. You will also see it sold as magnesium glycinate, which is essentially the same thing (we explain the naming in our guide to magnesium bisglycinate vs glycinate).

One thing worth knowing before you read any label: the weight of the compound is not the same as the amount of magnesium it provides. For example, our Magnesium Bisglycinate contains 1500mg of magnesium bisglycinate per serving, which provides 300mg of magnesium itself. When you compare products or add up your daily intake, use the magnesium figure.

The most common side effects

The side effects people report with magnesium supplements are mostly digestive:

Loose stools or diarrhoea
Nausea
Stomach cramps or discomfort

These are more likely at higher doses. Magnesium bisglycinate is generally considered gentler on the stomach than forms such as magnesium oxide or magnesium citrate, which are more often linked to a laxative effect. That is one of the main reasons people choose it.

If you do notice stomach upset, these steps often help:

Take your magnesium with food
Stick to the dose on the label rather than doubling up
Check whether other supplements you take also contain magnesium

How much magnesium is too much?

According to the NHS, adults aged 19 to 64 need about 300mg of magnesium a day (men) and 270mg a day (women), and most people should be able to get this from a varied diet. The NHS also says that taking 400mg or less a day of magnesium from supplements is unlikely to cause any harm.

Taking high doses of magnesium for a short time can cause diarrhoea. Much larger amounts, particularly in people whose kidneys cannot clear magnesium properly, can lead to too much magnesium in the blood. Signs include muscle weakness, low blood pressure and an irregular heartbeat. This is rare, but if you notice these symptoms, stop taking magnesium and get medical advice.

The easiest way to stay within sensible limits is to add up the magnesium in everything you take, including multivitamins, electrolyte drinks and combined products.

Who should speak to a doctor first?

Check with your doctor or pharmacist before taking a magnesium supplement if you:

Have kidney problems
Take antibiotics such as tetracyclines or quinolones, or bisphosphonates for bone health, as magnesium can affect how well they are absorbed
Take any regular medication
Are pregnant or breastfeeding

Does magnesium bisglycinate make you sleepy?

Magnesium is not a sedative, and drowsiness is not a recognised side effect. Many people simply prefer to take their magnesium in the evening because it fits into their routine. You can take it at whatever time of day suits you best.

Frequently asked questions

Is it safe to take magnesium bisglycinate every day?
For most healthy adults, yes, as long as you stick to the dose on the label and your total intake from supplements stays within the NHS guidance of 400mg or less a day.

Can magnesium bisglycinate cause diarrhoea?
It can, especially at higher doses, although bisglycinate is generally gentler on the stomach than forms such as oxide or citrate.

Can I take magnesium bisglycinate with a multivitamin?
Yes, but check the labels first. Many multivitamins also contain magnesium, so add the amounts together to make sure your total stays sensible.

Elevate Magnesium Bisglycinate

Elevate Magnesium Bisglycinate provides 300mg of magnesium per 2-capsule serving. Magnesium contributes to a reduction of tiredness and fatigue and to normal muscle function.

This article is for general information only and is not medical advice. If you have a health condition or take medication, speak to your doctor or pharmacist before taking a supplement.

Magnesium Bisglycinate Side Effects: What to Know Before You Take It