Magnesium deficiency:
the gap a blood test
can miss.

How common is magnesium deficiency in India?

Magnesium is involved in hundreds of enzyme reactions — turning food into energy, building protein, and keeping muscles, nerves, blood sugar and blood pressure working normally. In 2020, India’s ICMR-NIN raised its recommended intake to 440 mg a day for men and 370 mg for women, up from 340 and 310.1

You’ll often see the claim that “80% of Indians” are magnesium deficient. The best Indian data is more specific — and more telling: in a study of 1,006 adults in Moradabad, urban men ate about 415 mg a day and urban women about 316 mg, against 520 and 432 mg for their rural neighbours eating more whole grains.2 Both urban figures sit below today’s ICMR targets. Globally, an estimated 2.4 billion people — about 31% — don’t meet recommended magnesium intakes.3

This isn’t usually dramatic deficiency. Healthy kidneys hold on to magnesium when intake is low, so clear-cut deficiency from diet alone is uncommon.4 The more common picture is a quiet shortfall — intake that sits below need for years, especially for city-dwellers eating refined grains.

Magnesium deficiency symptoms: what to look for

Why Indian diets fall short on magnesium

1. Refined grains

Most of a grain’s magnesium sits in the bran and germ, which milling removes. White rice and maida keep only around a sixth of the magnesium of brown rice and whole-wheat flour.6 That’s the likely reason urban adults in the North Indian study ate so much less magnesium than rural adults.2

2. Phytate in everyday staples

Phytate, found in whole grains and legumes, binds magnesium in the gut. In a human study, adding phytate at whole-wheat-bread levels cut magnesium absorption from 32.5% to 13% — about 60% less.7 Soaking, sprouting and fermenting — traditional Indian techniques — lower phytate.

3. Diabetes, medicines and alcohol

Type 2 diabetes increases urinary magnesium loss, and so do long-term acid-reducing tablets (proton pump inhibitors such as omeprazole or pantoprazole), some diuretics (“water tablets”) and regular alcohol use.4 In a country with high rates of diabetes and widespread acid-tablet use, these matter.

4. Chronic stress

Stress and magnesium form a loop: stress raises the body’s magnesium losses, and low magnesium can make the stress response harder to settle.5

Why a standard blood test can miss it

Around 99% of your magnesium sits in bone, muscle and other tissues; only about 1% is in the blood.8 The body works hard to keep serum magnesium within a tight range (about 0.75–0.95 mmol/L), borrowing from its stores to do so. So a normal serum result doesn’t rule out a shortfall — researchers describe this as subclinical magnesium deficiency, and argue that most of it goes undiagnosed.8

A low serum magnesium, on the other hand, is meaningful and should be discussed with a doctor. If you’re concerned, ask whether a red-blood-cell magnesium test is available alongside the standard one.

Magnesium rich foods in Indian kitchens

Values per 100 g, rounded, from the ICMR-NIN Indian Food Composition Tables (ragi) and USDA FoodData Central (others).9,6

Best magnesium supplement in India: why the form matters

In a human comparison, magnesium oxide was absorbed at only about 4%, while chloride, lactate and aspartate reached 9–11%.10 A 2019 study showed why form beats headline dose: a product with 196 mg of magnesium in a better-dissolving formulation raised blood magnesium significantly more than a 450 mg pure-oxide tablet — whose effect couldn’t be told apart from normal daily variation.11

Magnesium bisglycinate binds magnesium to glycine, is gentle on the stomach, and has been rated “not of safety concern” by the European Food Safety Authority.12 It also carries glycine, a calming amino acid — about 2.7 g in a 440 mg serving of pure glycinate, close to the 3 g that improved sleep quality in human studies.13

Watch for “buffered” glycinate, which is padded with magnesium oxide to raise the magnesium number — so part of the dose is the poorly absorbed form, with about half the glycine. To check any label, divide the magnesium by the glycinate weight: about 12–14% means pure; 18% or more means buffered. Our buffered vs non-buffered guide shows worked examples, and the glycinate vs citrate vs oxide guide compares the forms.

Magnesium for sleep, stress and cramps: what the research shows

Sleep. In a 2025 randomised trial of 155 adults reporting poor sleep, magnesium bisglycinate improved insomnia scores over four weeks, with the biggest benefits in people eating the least magnesium.14 Pooling three trials in older adults with insomnia, magnesium shortened the time to fall asleep by about 17 minutes.15 Read more in our magnesium glycinate for sleep guide.

Stress. In 264 stressed adults with low blood magnesium, 300 mg of magnesium a day reduced perceived stress over eight weeks.16 A 34-trial analysis found 300 mg a day for one month was enough to raise blood magnesium.17

Cramps and recovery — the form matters. In pregnant women with leg cramps, 300 mg a day of magnesium bisglycinate halved cramp frequency in 86% of women, versus 60.5% on placebo.18 By contrast, trials using magnesium oxide for ordinary night cramps in older adults found it no better than placebo,19,20 and a similar pregnancy trial using magnesium citrate found no benefit.21 For gym-goers, 350 mg a day of magnesium glycinate reduced muscle soreness and improved how recovered people felt.22 If cramps are frequent, see a doctor to look for the cause.

What to do if you think you’re low in magnesium

1. See a doctor for red-flag symptomsPalpitations, numbness, tingling or muscle weakness need a proper check — and so does kidney disease, which changes how safe magnesium is.
2. Check your risk factorsDiabetes, long-term acid-reducing tablets, water tablets and regular alcohol all raise magnesium losses.
3. Eat for magnesiumAdd seeds, nuts, millets and pulses, and soak, sprout or ferment grains and legumes to absorb more.
4. Choose a well-absorbed supplementPick non-buffered bisglycinate, citrate or another organic form over oxide. In India, FSSAI caps each mineral in a supplement at the ICMR daily allowance — for magnesium, 370 mg for women and 440 mg for men. Loose stools are mostly linked to poorly absorbed forms such as magnesium oxide.
5. Give it timeMost studies measured changes after four to eight weeks of daily use.