Supplements 101: Magnesium for ME/CFS and Fibromyalgia
Why is Magnesium Important?
Magnesium is the fourth most abundant mineral in the body, required for over 300 enzymatic processes. It plays a vital role in DNA and protein synthesis, energy production (ATP), and maintaining a healthy balance of calcium, sodium, and potassium. Yet, magnesium often flies under the radar compared to other essential minerals.
For those with ME/CFS, fibromyalgia, and related conditions, magnesium may offer a range of benefits, from reducing inflammation to supporting brain and mitochondrial function. Let’s explore why magnesium matters and how to ensure you’re getting enough.
Why Magnesium Deficiency is So Common
Modern lifestyles and dietary trends have made magnesium deficiency more prevalent than ever. Factors include:
Depleted soils due to pesticide overuse, reducing magnesium content in crops.
Water treatment processes that remove magnesium from tap water.
Food processing that strips magnesium from grains and other staples, reducing magnesium content by up to 300%.
Medications like antacids, antibiotics, and blood pressure drugs, which interfere with magnesium absorption.
Aging, which naturally reduces magnesium absorption by as much as 30%.
In 1900, the average magnesium intake in the U.S. was 540 mg per day. Today, it’s down to just 250 mg—a level that falls far short of the daily recommended intake of 320 mg for women and 420 mg for men.
Why Testing for Magnesium is Tricky
Over 90% of the body's magnesium is stored in bone and muscle, making it hard to assess with standard blood tests. Most magnesium in the blood is bound to proteins and not detected in routine serum magnesium tests. Even "normal" serum magnesium levels can mask a subclinical deficiency.
Better diagnostic methods include:
Red blood cell magnesium testing, which offers a slightly better view of magnesium status.
Hair analysis, which may provide additional insights but is not commonly used.
Muscle biopsies, though not practical, are the most accurate.
Researchers suggest maintaining serum magnesium levels above 85 mmol/L to avoid deficiency symptoms.
The Link Between Magnesium and ME/CFS
Magnesium deficiency is likely more common in severe ME/CFS cases due to:
Immobilization and bed rest, which reduce magnesium levels.
Chronic inflammation, a hallmark of ME/CFS, which increases magnesium demand.
HPA axis dysregulation, exacerbated by magnesium deficiency, leading to elevated cortisol levels.
While studies on magnesium supplementation in ME/CFS and fibromyalgia are limited and often poorly designed, anecdotal evidence and related research suggest potential benefits.
How Magnesium Supports Health
Reduces Inflammation:
Magnesium deficiency triggers inflammatory pathways, increasing markers like CRP and TNF-alpha.
Adequate magnesium levels suppress these inflammatory responses and stabilize mast cells.
Improves Brain Health:
Magnesium binds to NMDA receptors in the brain, preventing overactivation by glutamate and calcium.
This modulation may help with neuroinflammatory conditions like depression and brain fog.
Supports the HPA Axis:
Magnesium regulates the stress response by dampening excess cortisol production. This helps rebalance the hypothalamic-pituitary-adrenal (HPA) axis, often disrupted in ME/CFS and fibromyalgia.
Relieves Migraines:
Clinical trials show magnesium supplementation can reduce migraine frequency, duration, and severity by up to 41%. Magnesium taurate is particularly effective for migraine relief.
How to Increase Magnesium Intake
Food Sources
Whole foods are the best source of magnesium, with 30–40% of dietary magnesium absorbed by the gut. High-fiber foods may further enhance absorption.
Top magnesium-rich foods include:
Seeds: Hemp seeds, pumpkin seeds.
Vegetables: Spinach, chard, avocado.
Dairy: Yogurt.
Fish: Oily fish (e.g., mackerel, salmon).
Other: Dark chocolate, mineral water, mollusks.
Magnesium Supplements
Supplements are a convenient option for those unable to meet their needs through food alone. However, be mindful of form, dose, and potential side effects.
Choose the Right Form:
Poor absorption: Magnesium oxide.
Moderate absorption: Magnesium citrate.
High absorption and fewer side effects:
Magnesium glycinate
Magnesium taurate (best for brain health and migraines)
Magnesium malate (ideal for fibromyalgia)
Magnesium orotate (cardiovascular benefits)
Dose:
The upper tolerable limit is 350 mg/day, but doses should be divided throughout the day to minimize gastrointestinal side effects.
Alternative Methods:
Topical magnesium: Magnesium oils and creams.
Magnesium baths: Epsom salt soaks.
Injections: For severe deficiency, injectable magnesium may be prescribed.
Bottom Line
Magnesium is an unsung hero for anyone managing chronic fatigue, fibromyalgia, or long COVID. From reducing inflammation to supporting mitochondrial energy production, magnesium is a vital nutrient that can play a significant role in symptom management.
If you suspect a magnesium deficiency, start by increasing your intake through food and, if needed, choose a high-quality supplement. As always, consult your healthcare provider to determine the best approach for your needs.
References
DiNicolantonio JJ et al. (2018) Subclinical magnesium deficiency: a principal driver of cardiovascular disease and a public health crisis. Open Heart. 5(1): e000668.
Uysal N et al. (2019) Timeline (Bioavailability) of Magnesium Compounds in Hours: Which Magnesium Compound Works Best? Biol Trace Elem Res. 187(1):128-136.
Innerarity S. (2000) Hypomagnesemia in acute and chronic illness. Crit Care Nurs Q. 23(2):1-19.
Tarleton EK, Littenberg B, MacLean CD, Kennedy AG, Daley C (2017) Role of magnesium supplementation in the treatment of depression: A randomized clinical trial. PLoS ONE 12(6): e0180067.
Schwalfenberg GK (2017) The Importance of Magnesium in Clinical Healthcare. Scientifica (Cairo). 2017: 4179326.
Dibaba DT, Xun P, He K. (2014) Dietary magnesium intake is inversely associated with serum C-reactive protein levels: meta-analysis and systematic review. Eur J Clin Nutr. 68(4):510-6.