Mood and stress · 15 minute read
Magnesium for anxiety: what the trials show, whether glycinate is worth it, and the other deficiencies linked to anxious moods.
Adrian Stone, nutritionist and naturopath
By Adrian Stone, BHSc (Nutritional Medicine), BHSc (Naturopathy), Living Holistic Health — part two of our Stuck in Fight or Flight series: magnesium for anxiety, the other nutrient deficiencies linked to anxious moods, and why testing comes before supplements.
Magnesium for anxiety has some trial support, mostly in people who are low in magnesium or mildly anxious, but the studies are small. Glycinate has not been shown to beat other forms. Low iron, B12, B6 and vitamin D are also linked to anxious moods, so testing first beats guessing from a social media reel.
Magnesium glycinate is having its moment. Social feeds are full of ‘calm in a capsule’. There is a real idea underneath it, though. The brain’s calming chemistry runs on nutrients, and some anxious people are genuinely low in them.
However, a supplement chosen from a reel is a guess. In Part 1 of this series, on how to reduce cortisol, I described a vicious circle. Stress drains magnesium, and low magnesium makes the stress response louder. This post looks at what that means for magnesium for anxiety, and at the other deficiencies worth ruling out. If you don’t test, you’re only guessing.
As in every part of this series, I keep two kinds of evidence side by side and label them. Traditional evidence is what food cultures and healing systems have documented over generations. Trial evidence is what modern human studies measure. Neither, on its own, tells you what suits you.
We don’t diagnose or treat anxiety or depression; that stays with your doctor. Our part is the nutritional, herbal and lifestyle work that sits alongside their care.
No single deficiency causes anxiety, but several are linked to it: low magnesium, iron deficiency, low vitamin B6 or B12, and low vitamin D. Omega-3 fats also matter. These are worth checking if anxiety comes with fatigue, poor sleep or a restricted diet. Correcting a deficiency supports treatment rather than replacing it.
In fact, the mechanism is fairly simple. GABA, the brain’s main calming messenger, needs vitamin B6 to be made. Magnesium dampens the brain’s excitatory signalling and the stress axis. Iron is needed to make serotonin and dopamine. So when one of these runs low, the nervous system is short of its raw materials.
In my framework of four root drivers, this is where a nutritional mismatch feeds sympathetic nervous system dominance. Consequently, a body that is already stressed has less in the tank to settle itself.
The evidence for magnesium for anxiety is promising but limited. Systematic reviews find most small trials report less self-reported anxiety, especially in people who are mildly anxious, have PMS or start with low magnesium. The trials are small, varied in form and amount, and often combine magnesium with other nutrients, so firm conclusions aren’t possible yet.
A 2017 review gathered 18 studies, all in groups thought to be vulnerable.1 Magnesium helped in four of eight samples of mildly anxious people and four of seven samples with premenstrual symptoms. However, it made no difference to anxiety after childbirth. Indeed, many trials gave magnesium alongside up to five other ingredients. The authors called the evidence suggestive, and they rated its quality as poor.
Similarly, a 2024 review of 15 trials found that five of seven anxiety studies reported improvement.2 The authors concluded that benefit is most likely in people whose magnesium is low to begin with. Meanwhile, a 2020 review across several mental health conditions found mixed results overall.3
To begin with, stress increases the magnesium lost in urine, and low magnesium appears to make the stress response more reactive. Researchers call it a ‘vicious circle’.4 Admittedly, most of that evidence is mechanistic or observational. Three of the review’s eight authors work for a consumer health company. Still, it explains why chronic stress and low magnesium so often turn up together.
In general, the signs include muscle cramps and twitches, poor sleep, tiredness, headaches, constipation and feeling wired. Notably, many of these overlap with anxiety itself. A standard blood test measures magnesium in serum, which can look normal even when body stores are low. Our post on magnesium deficiency covers food sources and the basics.
There’s no direct evidence that magnesium glycinate works better for anxiety than other forms. Trials have used a range of forms, and none compared glycinate head-to-head for anxiety. Glycinate is often promoted as better absorbed and easier on the gut. Even so, the form matters less than whether you were low in the first place.
Magnesium glycinate benefits are usually listed as better absorption and fewer bowel side effects. Those are practical points about tolerance, not evidence about anxiety. In contrast, ‘the calming form’ is an extrapolation. Specifically, glycine is an amino acid with its own small sleep studies, but those are not magnesium trials. This is the kind of single-answer story I push back on. Magnesium glycinate anxiety claims run well ahead of the research.
Rarely, if ever, in the research. In general, too much magnesium mainly causes loose stools. Importantly, it needs care with kidney disease and some medicines, including certain antibiotics and osteoporosis medicines. Our magnesium post covers this question in more detail.
Popular use
Soaking in Epsom salt, which is magnesium sulfate, is a popular way to wind down at the end of a day.
What the trials show
A 2017 review looked for evidence that meaningful magnesium crosses the skin and found it lacking; the authors could not recommend it.5 Two of the authors are linked to a company that sells oral magnesium. So enjoy the bath for the warmth and the quiet. Just don’t rely on it to fix a deficiency.
Low iron is linked to anxiety. A Taiwanese national study of adults with iron deficiency anaemia found a 52% higher risk of psychiatric disorders, including anxiety. Those who were treated with iron had a lower risk. Iron is easy to measure with a blood test, and it should never be supplemented without one.
Specifically, the study compared people with iron deficiency anaemia with people without it.6 The anaemia group had higher rates of anxiety, depression and sleep disorders. Even so, this was an observational study, so it shows an association, not proof that low iron caused the anxiety.
In particular, low iron is more likely with heavy periods, pregnancy or a vegetarian or vegan diet. Endurance athletes, frequent blood donors and people with gut conditions are also at risk. Above all, excess iron is harmful, which is why a blood test comes first.
Low vitamin B12 can contribute to anxiety, low mood, poor concentration and fatigue, and severe deficiency causes neurological and psychiatric symptoms. It’s more common in vegans, older adults, people on certain long-term medicines and those with gut absorption problems. Vitamin B6 is needed to make GABA, and one trial found high-dose B6 reduced anxiety.
At the severe end, B12 deficiency can cause neuropsychiatric symptoms. A 2024 review of 50 case reports found these settled in most treated cases.7 Still, most people with low B12 are nowhere near that end. Risk factors include vegetarian or vegan diets, long-term metformin or acid-suppressing medicines, and recreational nitrous oxide. It is also a simple blood test.
In a one-month UK trial, high-dose vitamin B6 reduced self-reported anxiety compared with placebo, while high-dose B12 only trended that way.8 A 2026 follow-up from the same group found B6 reduced depression symptoms in people who had them at the start.9
However, the trial used a high dose, above what can be sold off the shelf in Australia from June 2027. The TGA warns that vitamin B6 can cause nerve damage, felt as tingling, burning or numbness in the hands or feet. It says the risk cannot be ruled out even at lower doses.10
Moreover, B6 hides in many products, including magnesium and zinc products and multivitamins, often listed as pyridoxine or pyridoxal. Therefore, check every product you take for B6, and talk to your practitioner before taking it at all. This is promising research, not a reason to self-prescribe.
Low vitamin D is common in southern Australia in winter and is linked to low mood, but the evidence for anxiety is weaker. Meta-analyses find vitamin D supplements modestly improve depressive symptoms, especially in people who are deficient, yet show no clear effect on anxiety. It’s still worth checking and correcting, just not as an anxiety cure.
For instance, a 2024 analysis of 31 randomised trials found vitamin D reduced depressive symptoms.11 However, the same analysis found no significant effect on anxiety symptoms. Similarly, a 2020 review found benefits for negative emotions mainly in people with major depression or low vitamin D levels.12 I would rather tell you that than overstate it.
People in Geelong and the Bellarine are also at higher risk from May to September. Indoor workers, older adults, people with darker skin and anyone who covers up are most affected. How long it takes to feel better varies. The trials measured changes over two months or more.
Omega-3 fats may help. A meta-analysis of 19 trials with over 2,200 people linked omega-3 supplements to reduced anxiety symptoms. Benefits were clearer in people with a diagnosed condition and at higher intakes. Results aren’t consistent, though, and a 2024 analysis in heart patients found no benefit.
Overall, the 2018 review found a small-to-moderate effect, and the benefit showed up mainly in the higher-intake groups.13 By contrast, a 2024 review of six trials in people with coronary heart disease found no improvement in anxiety or depression.14 Still, oily fish such as salmon, sardines and mackerel remain the food source.
Traditional use
The traditional Mediterranean way of eating was recorded in Crete, the rest of Greece and southern Italy in the early 1960s. It was built on vegetables, legumes, wholegrains, fruit, nuts, olive oil and fish.15 Naturally, that pattern is rich in magnesium, B vitamins and omega-3 fats.
What the trials show
This one is a Geelong story. The SMILES trial, from Deakin University’s Food & Mood Centre, tested a Mediterranean-style diet in adults with moderate to severe depression.16 After 12 weeks of dietary support, about a third reached remission, compared with 8% of those given social support. That was a depression trial, not an anxiety trial, so it is research rather than a promise.
This is the food-first message I like best: the nutrients in this post come packaged together on a plate.
A broad multivitamin may help a little if your diet is patchy. A meta-analysis of eight trials in healthy people found multivitamin and mineral supplements reduced perceived stress and anxiety modestly over at least four weeks. They’re not a treatment for an anxiety disorder, and they can double up on nutrients like B6 if you take other products.
In that review, the effects on stress and anxiety were small to moderate, and there was no clear effect on depression.17 Equally, remember the TGA’s point about B6: a multivitamin plus a magnesium product can add up quickly.
In short, magnesium has some trial support, mostly in people who are low in it. Low iron and B6 have early evidence, with real safety cautions. Vitamin D and omega-3 are mixed for anxiety. The strongest food evidence comes from Mediterranean-style eating, tested in depression rather than anxiety.
Each layer is rated on its own: ●●● strong, ●●○ some, ●○○ limited. A long tradition is not evidence that something works or that it suits you.
Magnesium
Iron, B12 and B6
Vitamin D and omega-3
Multivitamins
Mediterranean-style eating
Epsom salt baths
General information only, not individual medical advice. Always discuss supplements and herbal medicines with your treating practitioner.
The only way to know whether a deficiency is part of your anxiety is to test. Iron studies, B12, vitamin D and magnesium can all be measured, and results guide what to correct and what to leave alone. Guessing risks missing a real deficiency or taking things you don’t need, including iron, which is harmful in excess.
My rule for any test is simple: do it if it will better inform the treatment plan and get a better result faster. Here, it usually does. We arrange and interpret iron studies, B12, vitamin D, magnesium (including red cell magnesium) and organic acids testing. Red cell magnesium is useful because serum magnesium can look normal when stores are low. Importantly, many of these are also standard blood tests your GP can order. Our post on organic acids testing explains what that test adds.
See your GP if anxiety is affecting work, sleep, relationships or daily life, or if you have panic attacks. Also see them if it comes with palpitations, weight loss or tremor, which can signal an overactive thyroid. Nutrients support treatment but don’t replace it. If you feel unsafe or are struggling to cope, call Lifeline on 13 11 14.
Notably, an overactive thyroid is a classic mimic of anxiety, which is one reason I like to look at the whole body. Please don’t stop or change a prescribed medicine because of anything you read here. If you take an antidepressant or anti-anxiety medicine, read our post on natural medicine alongside medication first.
When it comes to magnesium for anxiety, check your levels rather than guess. The best evidence is in people who are low to begin with, and no form has been shown to beat the others. Iron, B12, B6 and vitamin D matter too, and some of them carry real safety warnings when taken without a test.
We want the body to do most of the work; our job is to create the right conditions for it. For more on stress, sleep and mood, visit our mood and stress page.
If you would like your levels checked, we can arrange the tests and go through the results with you.
Geelong, Drysdale or telehealth
More in Stuck in Fight or Flight: Part 1: How to reduce cortisol · Part 3: Natural remedies for anxiety · Part 4: How to recover from burnout · Part 5: Perimenopause anxiety
There’s no proven best form. Glycinate is often promoted as well absorbed and easier on the gut. However, trials have not shown it to beat other forms for anxiety. Whether you’re low matters more than the form, so check with your practitioner first.
It varies. Trials ran from a few weeks to a few months. People who started with low magnesium were the most likely to notice a difference. If nothing has changed after a couple of months, magnesium probably isn’t the missing piece.
No vitamin calms anxiety on its own. B6 has one positive trial, and a genuine deficiency of iron, B12 or vitamin D is worth correcting for its own sake. Magnesium and omega-3 fats have the most research. Testing first is better than guessing, because some of these are harmful in excess.
Low B12 can contribute to anxiety, low mood and fatigue. It’s more likely in vegans, older adults and people on some long-term medicines, such as metformin or acid-suppressing medicines. It’s a simple blood test, so it’s worth checking rather than assuming.
There isn’t one that suits everyone. The most useful supplement is the one that corrects something you’re actually low in, which is why we test before recommending anything. Your GP or psychologist should still lead the care of an anxiety disorder.
Magnesium can interact with some medicines, including certain antibiotics and osteoporosis medicines, and it needs care with kidney disease. Check with your doctor or pharmacist before adding it to any medication, and don’t change a prescribed medicine on your own.
Free 14-day tracker
Wired at night, awake at 3am, flat by the afternoon? It may not be just stress. A free two-page guide from Adrian Stone shows what’s worth asking your GP about, with a 14-day tracker for your pattern.
General information only, not individual medical advice. Always discuss supplements and herbal medicines with your treating practitioner.
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Follow-ups 30 min · $89 · No referral needed
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