Medically reviewed by Dr. Reina Punj, MBBS, PG Diploma in Endocrinology (University of South Wales), Lead Physician, Excelgenics Clinical Panel.
You eat reasonably well. You sleep 7 hours. You’re not doing anything obviously wrong. Yet you wake up tired, your muscles cramp at random, and your mind feels foggy by mid-afternoon. These signs have many possible causes, and it is worth asking your doctor about them. One question that rarely comes up: when did you last think about your magnesium intake?
Reliable data on how many Indians are low in magnesium are limited, and headline percentages that circulate online do not come from robust studies. What is clear is that magnesium status is hard to measure, which is why low magnesium can go unnoticed. A key idea here is subclinical magnesium deficiency.
What Is Subclinical Magnesium Deficiency?
Subclinical magnesium deficiency describes a situation where a blood test comes back in the normal range, but the body’s stores may still be low. This can happen because less than 1% of the body’s magnesium is in blood serum. Around 50–60% is stored in bone, and most of the rest is inside soft tissues such as muscle.
A 2018 review in Open Heart by DiNicolantonio and colleagues argued that because serum magnesium is a poor guide to the magnesium stored in cells, many cases of magnesium deficiency are likely to go undiagnosed. This is the authors’ view in a review article; there is no single agreed test for subclinical deficiency.
Why Indians Are Specifically at Risk
Diets that rely heavily on refined grains, polished rice and processed foods tend to be lower in magnesium. Whole grains, pulses, nuts, seeds and dark leafy greens are the richest dietary sources of magnesium, and many everyday meals include less of them than they could.
Some additional factors can affect magnesium status:
- Certain medicines — Long-term use of proton pump inhibitors (acid-reducing medicines such as omeprazole) can lower magnesium levels, and loop and thiazide diuretics increase the amount of magnesium lost in urine. Do not stop any medicine without speaking to your doctor
- Health conditions — People with digestive conditions that affect absorption, type 2 diabetes or alcohol dependence are more likely to have low magnesium
- Age — Older adults tend to absorb less magnesium and lose more through the kidneys
Signs of Low Magnesium You’re Probably Ignoring
The early signs of low magnesium are non-specific and easily dismissed as everyday tiredness or stress, which is one reason low magnesium can go unnoticed. They can also be caused by many other conditions, so they are a reason to see a doctor, not a diagnosis.
According to the US National Institutes of Health, the signs of magnesium deficiency include:
Early signs:
- Fatigue and weakness
- Loss of appetite
- Nausea and vomiting
As deficiency worsens:
- Numbness or tingling
- Muscle contractions and cramps
- Seizures
- Personality changes
- Abnormal heart rhythms and coronary spasms
Severe deficiency:
- Low blood calcium and low blood potassium, because magnesium is needed to keep these minerals in balance
Palpitations, an irregular heartbeat, seizures or severe muscle spasms need prompt medical attention.
Separately, observational research has linked lower magnesium intake or status with type 2 diabetes, lower bone mineral density and migraine, while findings for blood pressure and heart disease are mixed. These are associations seen in studies, not proof that low magnesium causes these conditions, and not evidence that a supplement will prevent them.
A common pattern: magnesium deficiency fatigue and low energy can lead people to reach for extra caffeine and sugary snacks, rather than looking at the overall quality of their diet.
Why Your Doctor Probably Missed It
When patients report tiredness or cramps, magnesium deficiency is not always the first thing considered, because these symptoms have many possible causes, such as thyroid problems, anaemia or dehydration, that doctors rightly check first.
A magnesium test is often not part of a routine blood panel unless it is specifically requested. Even when it is done, a normal serum result does not fully rule out low body stores, so your doctor may consider your diet, medicines and symptoms together.
What You Can Do Starting Today
Start with food: whole grains, dal and other pulses, nuts, seeds and leafy greens. If your diet falls short, or your doctor thinks your magnesium status may be low, a supplement can help fill the gap. The form matters.
Not all magnesium supplements are absorbed equally. In one small study, only about 4% of the magnesium in magnesium oxide was absorbed. Organic and chelated forms, such as citrate and amino-acid chelates like bisglycinate, are absorbed better than oxide, and bisglycinate is generally well tolerated, although loose stools, nausea or stomach cramps can occur with any magnesium supplement.
The NIH upper limit for supplemental magnesium is 350 mg a day for adults, so do not combine magnesium products. If you have kidney disease, take magnesium only on medical advice, and leave a gap between magnesium and certain antibiotics or bisphosphonates.
If you’ve noticed several of these signs, speak to your doctor first. For help understanding which form to take, how much, and how Indian products compare, see our guide:
Best Magnesium Bisglycinate Supplement in India 2026
References
- DiNicolantonio JJ, O’Keefe JH, Wilson W. Subclinical magnesium deficiency: a principal driver of cardiovascular disease and a public health crisis. Open Heart. 2018;5(1):e000668. doi:10.1136/openhrt-2017-000668
- Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnesium Research. 2001;14(4):257–262. PubMed 11794633
- Walker AF, Marakis G, Christie S, Byng M. Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnesium Research. 2003;16(3):183–191. PubMed 14596323
- National Institutes of Health, Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals. ods.od.nih.gov
This article is for general education and is not medical advice. Food supplements are not intended to diagnose, treat, cure or prevent any disease. Consult a qualified healthcare professional before starting any supplement, particularly if you are pregnant, breastfeeding, have a medical condition or take medication.
