Magnesium Deficiency: The Silent Epidemic Affecting Most Women
The most common magnesium deficiency symptoms are muscle twitches and cramps, fatigue, poor sleep and mood changes such as irritability or anxiety. Magnesium is a cofactor in more than 300 enzyme reactions, so a shortfall can show up in many ways, from sleep to bone health.
Low magnesium is also easy to miss, because the standard blood test often looks normal until the deficiency is well advanced. This article covers the signs, why women are more likely to run low and what to do about it.
In brief
- Muscle spasms, fatigue and feeling anxious or restless are common signs.
- A serum magnesium test often misses early deficiency, because most magnesium sits in bones and cells.
- Women may need more magnesium during pregnancy and in the second half of the menstrual cycle.
- Food processing removes much of the magnesium from grains.
What is magnesium?
Magnesium is an essential mineral and the fourth most abundant cation in your body. About 60% is in your bones and nearly 40% in soft tissues, with less than 1% in your blood. Your body keeps the blood level stable by drawing on bone and tissue stores, which is why routine blood work can look fine while your cells are running low.
Magnesium also binds to ATP, the molecule that carries energy in your cells, and ATP can't work without it. That means every energy-using process, from contracting a muscle to making DNA, depends on magnesium. It belongs in any discussion of nutrients for energy, alongside the B vitamins.
How common is low magnesium?
Magnesium is one of several common nutrient deficiencies in women. For comparison, about 41.6% of US adults are low in vitamin D (Forrest & Stuhldreher, Nutrition Research 2011), and B12 deficiency affects about 6% of adults under 60, with vegans at far higher risk (Allen et al., American Journal of Clinical Nutrition 2009).
Some researchers think magnesium shortfalls may be even more widespread than these. Unlike vitamin D, which your skin makes from sunlight, magnesium has to come from food. Refining grains can remove up to 80% of their magnesium, and some argue that farming practices have lowered the mineral content of soil and crops, although that is debated.
What causes magnesium deficiency in women?
Usually it's a mix of eating too little and losing too much. Diets high in processed food supply less magnesium. Stress may add to the problem: in a fight-or-flight state your body excretes more magnesium in urine, so long-term stress may wear down your stores.
High intake of caffeine, alcohol and sugar can reduce how much magnesium you keep. Phytates in some grains and legumes can bind magnesium before it's absorbed, so even a high-fiber diet can lower availability. Hormones matter too: many women's magnesium dips before their period, and research suggests this may contribute to PMS symptoms.
Signs of magnesium deficiency
1. Muscle twitches and cramps
This is the classic sign: an eye twitch that won't stop, a calf cramp at night, or general stiffness. Calcium tells a muscle to contract and magnesium helps it relax. Without enough magnesium, muscle fibers can stay partly contracted, which leads to spasms and tension.
2. Mental fatigue and brain fog
Magnesium is needed for mitochondria, the parts of your cells that produce energy, so low levels can leave you mentally drained as well as physically tired. Magnesium also helps regulate GABA, the brain's main calming chemical. When magnesium is low, your nervous system can become overexcited, adding to fatigue and a sense of overwhelm.
3. Poor sleep
Magnesium supports your circadian rhythm and may play a part in melatonin production. By acting on GABA receptors, it also helps your brain settle at night. Women with low magnesium often describe feeling "tired but wired": exhausted, but unable to switch off.
4. Mood changes and anxiety
Low magnesium is linked with irritability, restlessness and a lower tolerance for stress. Some researchers have found an association with mood disorders, possibly through magnesium's role in the hypothalamic-pituitary-adrenal (HPA) axis, which controls the stress response.
Why it's hard to detect
Your body keeps blood magnesium in a narrow range because your heart rhythm depends on it. It will draw on cell and bone stores to do that, so the standard serum test can be normal while your tissues are depleted. This is one reason low magnesium is often missed at check-ups.
A red blood cell (RBC) magnesium test measures the magnesium inside cells and is more informative, but it still doesn't capture total body stores. Many practitioners look at your symptoms and diet alongside test results.
Magnesium is also needed to activate vitamin D. Low vitamin D is associated with more infections and autoimmune conditions, and vitamin D receptors are found on nearly all immune cells (Aranow et al., Journal of Investigative Medicine 2011), so the two are worth checking together.
Magnesium and bone health
Calcium gets most of the attention, but magnesium matters for bones too. It's needed to release parathyroid hormone, which controls blood calcium, and the enzymes that turn vitamin D into its active form depend on it. Without enough magnesium, even high-dose vitamin D may not work well. If you take a multivitamin, it helps to know how these nutrients balance each other (see our women's multivitamin guide).
How to get more magnesium
Start with food. Dark leafy greens such as spinach and kale, pumpkin seeds, almonds, black beans and dark chocolate are all good sources. Try to include one at every meal: pumpkin seeds on your morning yogurt, or sautéed greens with dinner.
If you're under a lot of stress or have digestive problems, food alone may not make up a long-standing shortfall. A magnesium supplement can help. Look for well-absorbed forms such as magnesium glycinate or citrate. Our article on magnesium, vitamins and sleep covers the sleep side in more detail.
Where Go Wise Multivitamin fits
Go Wise Multivitamin is a powder stick you pour onto your tongue, with no water needed and a natural berry flavor. Each stick has vitamins A, C, D3, E, B6 and B12, niacin, pantothenic acid, biotin, folic acid, zinc and chromium, plus elderberry extract and kelp as a natural source of iodine. It's vegan, gluten-free and has no artificial colors or flavors. It doesn't contain magnesium. For that, our Calm + Restore magnesium glycinate is a separate daily capsule. Every batch is third-party tested by Eurofins for heavy metals and microbial contamination, and it is made in a GMP-certified facility.
If you recognize several of the signs above, talk to your healthcare provider about your symptoms and diet, and ask whether an RBC magnesium test makes sense for you.
Frequently asked questions
How long does it take to reverse magnesium deficiency symptoms?
It depends on how low you are and how you replenish. Some people notice fewer muscle twitches or better sleep within 1 to 2 weeks of steady intake. Rebuilding bone and tissue stores can take 3 to 6 months of consistent supplementation and diet changes.
Can I take too much magnesium?
It's hard to get too much from food, but too much from supplements can cause diarrhea or cramping, because magnesium draws water into the bowel. Very high doses can be toxic, so follow the recommended daily allowance (RDA) and check with a professional.
Which magnesium is best for anxiety and sleep?
Magnesium glycinate is often recommended because it's bound to glycine, a calming amino acid. It's also well absorbed and less likely to have a laxative effect than forms like magnesium oxide.
Why didn't my doctor find my magnesium deficiency in my blood test?
The standard test measures serum magnesium, which is only about 1% of the magnesium in your body. Your body keeps that level stable even when your cells and bones are depleted. An RBC magnesium test is generally better at detecting chronic deficiency.
Does caffeine cause magnesium deficiency?
Caffeine is a mild diuretic and can increase how much magnesium your kidneys excrete. A moderate cup of coffee is unlikely to cause a deficiency on its own, but high caffeine intake combined with a low-magnesium diet can speed up depletion.
References
- Forrest & Stuhldreher. Nutrition Research. 2011.
- Allen et al. American Journal of Clinical Nutrition. 2009.
- Aranow et al. Journal of Investigative Medicine. 2011.
This article is for general information and isn't medical advice. Talk to your healthcare provider before starting a supplement, especially if you are pregnant, nursing or taking other medication.
