10 Signs of Magnesium Deficiency in Women

By Dalia Harush RD, MS CDN

Magnesium is involved in over 300 processes in the body: energy production, hormone signaling, nerve function, muscle contraction, and sleep regulation among them. Your body relies on it daily.

It's also one of the most commonly depleted minerals. Research estimates that a significant portion of adults in developed countries don't meet the recommended daily intake.¹ For women specifically, the combination of chronic stress, hormonal fluctuations, caffeine, and diets high in processed foods creates ideal conditions for depletion — often without obvious warning signs until the deficit is significant.

Here are ten signs your body may be running low.

1. Constant fatigue

Fatigue that doesn't resolve with sleep is one of the most reported symptoms of low magnesium. Magnesium is essential to ATP synthesis, the process your cells use to convert food into usable energy. A study published in the Journal of Nutrition found that people with low muscle magnesium levels required more energy and more oxygen to perform the same low-level activities as those with adequate levels, meaning their bodies were working harder for the same output.²

2. Sugar cravings

That energy deficit connects directly to cravings. Persistent cravings for sweets, especially in the afternoon, can reflect impaired cellular energy production rather than a lack of willpower. When your cells can't generate energy efficiently, your body looks for the fastest fuel it can find. Magnesium's role in glucose metabolism means low levels can directly drive cravings for quick sugar.³

3. Trouble sleeping

Magnesium may help activate GABA receptors in the brain. GABA is your brain's main calming neurotransmitter — it quiets neural activity and prepares your body for sleep. Low magnesium has been associated with difficulty falling asleep, frequent waking, and reduced sleep quality. A 2025 randomized, double-blind, placebo-controlled trial in adults aged 18 to 65 found that magnesium bisglycinate supplementation produced significantly greater reductions in insomnia severity compared to placebo, with the greatest improvements in those with lower dietary magnesium intake.⁴

4. Muscle tension or cramps

Calcium triggers muscle contraction; magnesium may help enable relaxation. Without adequate magnesium, that balance can tip toward sustained tension, resulting in tight muscles, soreness, and cramping. A 2017 literature review concluded that magnesium supplementation may be effective in the prevention of dysmenorrhea, the clinical term for painful menstrual cramps.⁵

5. Mood swings or irritability

Magnesium may help regulate serotonin and dopamine, two neurotransmitters central to mood stability. It may also help modulate your stress response. When magnesium is low, the nervous system can become more reactive, potentially contributing to irritability, anxiety, and emotional dysregulation.⁶

6. Headaches

Magnesium may play a role in blood vessel tone and nerve signal transmission. Low magnesium levels have been associated with increased headache frequency, and magnesium supplementation has been studied as a preventive intervention for migraines.⁷ If you experience hormonal headaches around your cycle, magnesium deficiency is worth investigating.

7. PMS symptoms

Women with PMS have been found to have lower magnesium levels compared to women without symptoms.⁸ Beyond the cramping and mood shifts already covered, low magnesium may also contribute to bloating and the general feeling of being off in the week before your period — symptoms tied to how magnesium influences fluid regulation and nervous system tone during the luteal phase.

8. Brain fog

Magnesium may support synaptic plasticity, which is your brain's ability to form and strengthen neural connections. Low magnesium has been associated with impaired nerve signal transmission and reduced cognitive clarity, including difficulty concentrating and mental fatigue.⁹

9. Afternoon energy crashes

Recurring afternoon crashes often reflect blood sugar instability. Magnesium acts as a cofactor for insulin, meaning it helps insulin do its job of moving glucose into your cells for energy. When magnesium is low, that process may become less efficient, leading to the spike-and-crash pattern many women experience mid-afternoon.¹⁰

10. Feeling chronically stressed

Chronic stress depletes magnesium through increased excretion, and low magnesium amplifies stress reactivity in return. The result is a feedback loop: stress depletes magnesium, low magnesium makes stress harder to manage, which depletes magnesium further.¹¹

Why standard testing often misses low magnesium status

Standard serum magnesium blood tests are unreliable indicators of true magnesium status. Only about 1% of your body's magnesium is in your blood. The rest is stored in bone and soft tissue. Blood levels can appear normal even when your cellular stores are significantly depleted.¹²

If you're experiencing several of the symptoms above, that's more meaningful than a normal blood test result.

Restoring magnesium levels

Magnesium deficiency is addressable. Many women notice improvements with consistent supplementation over 4 to 6 weeks:

• Better energy and afternoon stamina

• More restful sleep

• Improved mood stability

• Reduced cramping

• Sharper mental clarity

Magnesium glycinate is particularly well-suited for replenishment. It absorbs well, is gentle on digestion, and the glycine it's bound to has its own calming effect on the nervous system.

 

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References

1. Rosanoff A, et al. Suboptimal magnesium status in the United States. Nutr Rev. 2012;70(3):153–164.

2. Lukaski HC, Nielsen FH. Dietary magnesium depletion affects metabolic responses during submaximal exercise in postmenopausal women. J Nutr. 2002;132(5):930–935.

3. Barbagallo M, Dominguez LJ. Magnesium and type 2 diabetes. World J Diabetes. 2015;6(10):1152–1157.

4. Schuster J, et al. Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nature and Science of Sleep. 2025.

5. Parazzini F, et al. Magnesium in the gynecological practice: a literature review. Magnesium Research. 2017;30(1):1–7.

6. Pickering G, et al. Magnesium status and stress: The vicious circle concept revisited. Nutrients. 2020;12(12):3672.

7. Mauskop A, Varughese J. Why all migraine patients should be treated with magnesium. J Neural Transm. 2012;119(5):575–579.

8. Sherwood RA, et al. Magnesium and the premenstrual syndrome. Ann Clin Biochem. 1986;23(6):667–670.

9. Slutsky I, et al. Enhancement of learning and memory by elevating brain magnesium. Neuron. 2010;65(2):165–177.

10. Guerrero-Romero F, et al. Oral magnesium supplementation improves insulin sensitivity. Diabetes Metab. 2004;30(3):253–258.

11. Pickering G, et al. Magnesium status and stress. Nutrients. 2020;12(12):3672.

12. Workinger JL, et al. Challenges in the diagnosis of magnesium status. Nutrients. 2018;10(9):1202.