Magnesium Deficiency Signs You're Probably Missing (And Why Your Supplement May Not Be Fixing Them)
Magnesium Problems, Why isn't Magnesium Working?
Many patients start magnesium on their own, and for good reason! Some take it because they've heard it will help their sleep, relieve the muscle cramps, or even get them pooping more. Maybe it helped a little, maybe it helped a lot, but maybe the results have plateaued or the problem is better, but still there. Even though magnesium deficiency is one of the most common mineral deficiencies, how much it helps can really depend on several things. It's estimated about 31% of the world population, 2.4 billion people, don't get the recommended daily intake!
Signs of Magnesium Deficiency, some you might know already know and some you don't!
Magnesium is a critical cofactor in over 300 different enzymes in the body, and 53% of our total body magnesium is estimated to be in our bones.
Most common magnesium deficiency symptoms:
But did you know these are also symptoms of magnesium deficiency:
Constipation, magnesium plays a role in our motility
Osteopenia and osteoporosis (with calcium, vitamin D and vitamin K2)
impaired liver detoxification
Hypertension (high blood pressure)
Cardiac Arrhythmias
Not all magnesium is the same:
Type | Absorption | Strengths |
Magnesium oxide | Poorly absorbed | Pulling water into the bowels and softening the stool, commonly prescribed for constipation |
Magnesium citrate | Excellent absorption | Also great at softening stools, also great for constipation |
Magnesium taurate | Good absorption | May better support cardiovascular function |
Magnesium malate | Good absorption | May have better effects on the muscles |
Magnesium glycinate / bisglycinate | Excellent absorption. | Great for muscle tension and sleep, mild calming effect, less effects on the bowels |
Magnesium L-Threonate | Good absorption | Crosses into the nervous system, May help cognition. |
Magnesium Chloride | Decent absorption | Commonly in very low doses in electrolyte formulas, higher doses generally cause diarrhea |
Magnesium sulfate | Topical and IV use | Generally used for intravenous (IV) administration. Also what is found in epsom salt! Mainly a laxative when taken orally. |
Why a "normal" blood test doesn't rule it out
Magnesium levels can be tested a number of ways, but a standard serum magnesium test doesn't tell us much about this nutrient's levels since it's mostly intracellular, meaning it's inside the cells. You need an intracellular test like RBC (red blood cell) magnesium to really assess tissue levels. Serum magnesium levels can come back completely normal, while the cells themselves are starved. Both are standard labs, covered by health insurance when ordered by your provider, and can be found on many micronutrient panels. This is also a great way to find out if your magnesium or supplements are working and being absorbed properly.
If magnesium's off, it's often not traveling alone
Nutrient deficiencies rarely travel alone. Many different minerals are commonly low together and testing should absolutely include assessing other minerals, as well as vitamins like B6, B12 and Vitamin D at a minimum. We find low omega-3 levels, low vitamin D and low B12 very common on routine blood work. Minerals like zinc, copper, magnesium, and chromium are also very common and easily tested via blood or hair.
Not everyone needs testing, some people just need the right form and dose. If you've tried a few things and still feel your magnesium supplement isn't helping enough, it's possible more is just deficient than magnesium, and a nutrient panel is a reasonable next step.
You can order your own mineral and nutrient tests, no insurance or appointment needed. Choose to meet with one our providers who can help with interpretation, or self-interpretation.
About Pacific Clinic of Natural Medicine
Pacific Clinic of Natural Medicine is a naturopathic and functional medicine clinic in Portland, Oregon, serving patients in-person and virtually throughout Oregon and Washington, with functional wellness consulting available nationwide. Our physicians are licensed naturopathic doctors — the original root-cause practitioners — specializing in hormones, gut health, nutrient status, thyroid, autoimmune conditions, chronic fatigue, and more.
📍 511 SW 10th Avenue, Suite 707, Portland, OR 97205 | 📞 503-894-8977 | pacificnaturalmedicine.com
Frequently Asked Questions
Why isn't my magnesium supplement working?
A few common reasons: the form you're taking may be poorly absorbed (like magnesium oxide), your body may need more time or a higher dose to replenish stores, or the underlying issue may involve more than magnesium alone. Testing can help clarify which of these applies to you.
Does magnesium show up on a normal blood test?
Not reliably. Standard serum magnesium only reflects a small fraction of your body's total magnesium, since most of it is stored inside cells and in bone. It's possible to have a completely normal serum magnesium result while your tissues are still low. RBC (red blood cell) magnesium testing gives a better picture of intracellular levels.
What's the best absorbed form of magnesium?
It depends on your goal. Magnesium citrate and glycinate are both well absorbed; glycinate tends to be gentler on the digestive system and is often chosen for sleep or muscle tension, while citrate's mild laxative effect makes it useful for constipation. Magnesium oxide is poorly absorbed and works mainly by pulling water into the bowel rather than raising tissue magnesium levels.
Is RBC magnesium testing covered by insurance?
Yes — RBC magnesium is a standard lab test, not a specialty or out-of-pocket-only test, and is typically covered by insurance when ordered by your medical provider.
Can I be magnesium deficient even if I eat well?
Yes. Absorption, stress, certain medications, and other nutrient deficiencies can all affect magnesium status independent of diet. If magnesium is low, it's also common for other nutrients — like B vitamins, vitamin D, or zinc — to be low at the same time.
References
Razzaque MS. Magnesium: Are We Consuming Enough? Nutrients. 2018;10(12):1863. (Global/US magnesium intake inadequacy) — https://pmc.ncbi.nlm.nih.gov/articles/PMC6316205/
Institute of Medicine. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. National Academies Press; 1997. (Body magnesium distribution, bone storage, serum vs. intracellular status) — https://www.ncbi.nlm.nih.gov/books/NBK109816/
de Baaij JH, Hoenderop JG, Bindels RJ. Magnesium in Man: Implications for Health and Disease. Physiol Rev. 2015;95(1):1-46. (Magnesium as enzymatic cofactor, over 300 enzyme systems)
Dominguez L, Veronese N, Barbagallo M. Magnesium and the Aging Process. Nutrients. 2024 (or similar aging/muscle-function review). — could substitute the Barbagallo & Dominguez body-distribution paper you already have
Al Alawi AM, Majoni SW, Falhammar H. Magnesium and Human Health: Perspectives and Research Directions. Int J Endocrinol. 2018;2018:9041694. (General overview: deficiency signs, cardiovascular/hypertension links, arrhythmia)
Walker AF, Marakis G, Christie S, Byng M. Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnes Res. 2003;16(3):183-191. (Citrate vs. oxide/chelate absorption)
Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnes Res. 2001;14(4):257-262. (Oxide vs. other forms fractional absorption)
Elin RJ. Assessment of magnesium status for diagnosis and therapy. Magnes Res. 2010;23(4):S194-198. (Serum vs. RBC/intracellular magnesium as a status marker)
Fiorentini D, Cappadone C, Farruggia G, Prata C. Magnesium: Biochemistry, Nutrition, Detection, and Social Impact of Diseases Linked to Its Deficiency. Nutrients. 2021;13(4):1136. (General deficiency signs, osteoporosis, cardiovascular)
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