Magnesium plays so many roles in the body and interacts with so many systems and processes that it can be hard to tell when you are not getting enough of the mineral. That said, there are some low-magnesium symptoms that dietitians say may reveal that you need to incorporate more magnesium-rich foods into your diet.
“Magnesium is one of those under-the-radar minerals that quietly powers hundreds of essential processes in the body,” says registered dietitian Samantha Peterson. Magnesium assists the body with energy production, helps maintain healthy blood pressure and blood sugar levels and supports nerve and muscle function.
While true magnesium deficiency is rare, research consistently shows that many adults get less magnesium than they should. That is largely because plenty of people do not eat enough vegetables, which are naturally rich in magnesium, explains nutrition scientist Erin Barrett. Many refined and ultra-processed foods are also stripped of minerals during manufacturing, which further lowers intake.
Some people simply need more magnesium than others, adds dietitian Amy Davis. Older adults and people with certain health conditions such as gastrointestinal disorders, type 2 diabetes and substance use disorders, along with those taking particular medications, may have a harder time absorbing magnesium or may lose more of it.
Because magnesium deficiency does not always cause obvious symptoms, it can be tricky to know if you are getting enough of the mineral. Still, there are some subtle and not-so-subtle signs that your intake may be too low. Below, experts share the symptoms that may be linked to low magnesium, plus what to do if you suspect the mineral could be part of the problem.
Signs of low magnesium
Fatigue
Persistent tiredness can be an early clue that magnesium is running low. “Magnesium is essential for making ATP—the main energy molecule in your cells,” Barrett says. “Without enough of it, your body can’t produce or use energy efficiently, which can leave you feeling tired or weak.” This is one of the most common signs of low magnesium. Registered dietitian Matt Landry suggests watching for “persistent fatigue that doesn’t improve with rest,” rather than the usual end-of-day tiredness.
Muscle cramps and spasms
Low magnesium can make muscles cramp, twitch, spasm and tingle and in some cases may even contribute to seizures or repetitive eye movements (nystagmus), Barrett explains. Magnesium helps regulate calcium and potassium, two electrolytes that influence how muscles and nerves fire. “When magnesium is low, nerves and muscles become more excitable,” Barrett says. That can leave muscles feeling weaker, twitchier or simply different from usual, such as “waking with tight calves” or “having muscle cramps at night,” Peterson notes.
Anxiety or irritability
Feeling unusually stressed, anxious or snappy for no clear reason can sometimes point to low magnesium. “Magnesium is a key player in calming the nervous system,” Peterson says. It helps regulate neurotransmitters, including feel-good chemicals like dopamine and serotonin, and fight-or-flight hormones like epinephrine. “When [magnesium is] low, the brain and muscles can go into overdrive, making you feel on edge, tense or mentally revved up,” she explains. That shift can show up as unexplained stress or anxiety, or simply feeling more irritable than usual.
Irregular heartbeat
Any new sensation of the heart racing, fluttering or beating irregularly warrants a chat with a doctor. In some cases, low magnesium may be part of the picture, Barrett, Davis and Landry note. “Magnesium plays a role in stabilising electrical activity in the heart,” Davis explains. When levels drop, that electrical signalling can become less stable, which may contribute to a fast or irregular heart rhythm.
Headaches
Headaches or migraines that become more frequent can also be a subtle sign. “Magnesium influences nerve transmission and blood vessel function in the brain,” Barrett says. “Deficiency has been linked to an increased risk of migraines in some people.” Not everyone with low magnesium will notice this, but if headaches are becoming a regular visitor alongside other symptoms, it is worth mentioning to a health professional.
Trouble sleeping
Low magnesium can leave you feeling drained and it can also disrupt sleep itself. Falling asleep and staying asleep may feel harder, or you might wake up feeling completely unrefreshed. “If someone is feeling ‘wired but tired’ or having trouble falling asleep despite being exhausted, I often take a closer look at magnesium,” Peterson said. Your mind may race at night or sleep can feel light and broken, Barrett added. Low magnesium may be part of the problem and improving your intake could help your sleep, but always check with your doctor before adding supplements.
High blood pressure
Because magnesium helps regulate blood pressure, not getting enough can raise the risk of hypertension, Barrett and Davis explained. “Magnesium helps relax blood vessel walls, supporting healthy circulation and normal blood pressure levels,” Barrett said. Research suggests that increasing magnesium intake through food or supplements may help lower blood pressure and in turn reduce the risk of heart disease or stroke.
Mood swings
Low magnesium can also show up in your mood. Davis and Landry note that it may leave you feeling flat, low or not quite like yourself. “Magnesium helps regulate [your] neurotransmitters and stress response,” Davis said. When those systems are out of balance, mood swings, what Landry called “personality changes,” or mild depression can emerge. “Think of [magnesium] as your body’s chill-out mineral,” Peterson said. “Without it, things start to misfire.”
Digestion issues
Low magnesium can also show up in the gut. In some people it may contribute to constipation or changes in bowel habits, Peterson says. Because these symptoms (like many low-magnesium signs) can be linked to a range of other health conditions, it helps to look at the bigger picture. “A red flag combo?” Peterson says. “Constipation and chronic stress.” If digestion has changed and you are also dealing with fatigue, muscle cramps or ongoing tension, it is worth raising with a health professional.
Sugar cravings
Suddenly craving something sweet more often than usual can sometimes be a clue too. Low magnesium may sit behind a growing sweet tooth, Peterson says. Magnesium helps regulate blood sugar and low levels can make it harder to keep blood glucose in a healthy range, Barrett explains. Blood sugar swings, such as dips (hypoglycaemia) or spikes (hyperglycaemia), can drive stronger hunger and cravings, which may show up as a sudden pull towards sugary foods.
Weak bones
Magnesium plays a quiet but important role in bone strength. “[It] supports bone structure and helps regulate calcium and vitamin D—two nutrients essential for strong bones,” Barrett says. Over time, consistently low intake of magnesium “may contribute to reduced bone density,” she explains. Davis and Barrett note that this can eventually increase the risk of osteoporosis, a condition in which bones become weak, fragile and more likely to break.
What to do if you suspect you have low magnesium
The good news is that if several of these symptoms are linked to low magnesium, improving intake can often help. Landry recommends first leaning on food. Magnesium-rich options include pumpkin seeds, almonds, leafy green vegetables, brown rice and black beans. Building these into meals and snacks regularly can support healthier levels over time.
A magnesium supplement may also be useful for some people, but there are many different forms and each may suit different concerns, such as sleep difficulties or digestive issues. Before starting any supplement, it is important to talk with a doctor or other qualified health professional. They can arrange a blood test if needed, assess medications and medical history and suggest the most appropriate dose and form.
Dietary supplements are intended to complement the diet. They are not medicines and are not designed to treat, diagnose, mitigate, prevent or cure diseases. Extra care is needed during pregnancy and breastfeeding, and supplements for children should only be given on the advice of their healthcare provider.
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