Meds & Supplements, Treatment

Debilitating Nausea Caused By High(ish) Magnesium Dose

white capsulesWoo hoo! I feel human again and it’s all because I stopped taking magnesium. Yep, magnesium, the wonder supplement that helps so many people with migraine and chronic daily headache. I don’t think magnesium itself is to blame, but that the dose was too high. Since I can’t even take a multivitamin without nausea, I was hyper-aware as I increased from my starting dose of 100 mg. Or so I thought.

At 333 mg per day, it was within the normal dose range for treating headaches of 200-500 mg per day. It was also within the recommended daily allowance of 350 mg. I’ve discovered that allowances and ranges are like speed limits: A guideline you’re not supposed to exceed, but that you don’t have to meet.

Practically every health care provider I’ve seen has recommended magnesium to me. I’ve taken it on and off over the last five years, although this is the first time I’ve taken it consistently for more than a few weeks. Because I’ve read so much about it and had it prescribed before, I thought I could adjust the dose myself just fine. I figured I’d be fine if I stayed at or under the RDA. I unwittingly fell for the myth that medications, vitamins and supplements sold over-the-counter are harmless.

The good and frustrating news: My overall head pain was less and I had fewer migraines during the time I was horribly nauseated. I’m guessing that means the magnesium helped some. I think once my system flushes the current round of magnesium, I’ll have my different vitamin and mineral levels tested. I’ll also make myself keep a diary of my symptoms and doses. I wouldn’t want to go through these last six weeks again. I felt horrible and was so scared of what might be wrong with me.

I haven’t had any blood tests, so I’m not positive the nausea was caused by excessive magnesium. But when debilitating nausea that began about the time I increased my dose goes away when I stop taking the pills, the evidence is strong enough for me.

What is your experience been with magnesium? Please leave a comment below or chime in on the online support group and forum.

26 thoughts on “Debilitating Nausea Caused By High(ish) Magnesium Dose”

  1. I’m so relieved to read these posts. I’ve been taking CalmX which is a powdered form of magnesium which you add to water and sip throughout the day. I never connected the dots as I started feeling nauseous and had terrible bloating /distended belly. I was trying to figure out what might be causing this. So I’m stopping magnesium immediately

  2. hello everybody
    Just started taking magnesium citrate last night. I took 2 and I am feeling nauseous this morning. can it be the magnesium?


  3. hello, ive had Migraines for 40 years, with Aura the past 15 years, ive taken Magnesium with Calcium in the past and it seriously stopped almost all of my Migraines and normal headaches!……reducing them to maybe 3 or 4 a year….since Okt ive had back to back Migraines with Aura which is very debilitating and horrible, ive been told to take Magnesium again which ive done for the past few weeks and have now horrible nausea and stomach cramps every day, i couldnt find the brand i took before and this one is Magnesium 400 with vit b1,b6 and b12….i thing the one with calcium is the most effective for Migraines so i will try that again at a lower dosage, i dont remember having this nausea the first time i took it so i guess it depends on the type?!….also, if you do have frequent headaches or Migraines Magnesium DOES work so dont give up on it, just find the one that suits you best and start at a low dosage to avoid the side effects.

  4. I am magnesium deficient and have 6 hour drips at the hospital. I was advised to take magnesium supplements. I bought some tablets 500mg but now my stools are black and I feel very sick not long after taking it. I am going to stop taking it. it really isn’t worth it.

  5. Thank you for these posts. I have been suffering migraines sometimes on a daily basis and have been getting increasingly nauseous this last week. Bummer because it really works for me in stopping the pain. I will decrease the dose and see if that does the trick.

    1. Ann, I recommend trying a different form of magnesium. Different types are better absorbed than others and so they have fewer side effects. I was able to take about 700 mg of Blue Bonnet’s buffered chelaged magnesium ( without problems. I now take 1,050 mg of monomagnesium malate ( with no side effects. The book The Magnesium Solution for Migraine ( has good information on the magnesium types with the fewest side effects.

      Also, there’s a chance something else could be the source of your nausea. I may have been mistaken about magnesium as the source of my nausea. It could have just been that my migraine symptoms were getting worse. The most common side effect is diarrhea. When I take too much magnesium now, I do not have any nausea, but do have diarrhea.

      Take care,

  6. I have been on 2x magnesium amino acid chelate 750mg (equivalent magnesium 150mg) before bed for muscle spasms that wake me up and mean I cannot get to sleep for 8 weeks. I forgot last night and on taking them this morning on an empty stomach I am very nauseous. I had magnesium as a drink a week ago and was nauseous for nearly a day. I am concluding it needs to be taken with or after food. Does anyone know anything about this?

  7. I just added b complex and b6 plus magnesium. I’m taking others including but not limited to multi, folic and biotin plus hair pills all in an attempt to keep my hair. I’m a 65 y old woman. It is most likely male pattern baldness but I do get some results. Rogaine causes rashes. Anyway, I guess I ought to do process of elimination. The nausea is hard to deal with.

  8. I have been taking very high doses of mag cit plus mag malate because I have ME/CFS plus I have been getting almost daily migraines or headaches (mainly migraine). Only today I have researched this and it says it can be a vasodilator and I know this is the last thing I need.

    Its only Sumatriptan plus paracetamol with caffeine that stands any chance of getting rid of the migraine first thing in the morning. My migraines have been getting worse and worse and I have been taking around 900 – 1000 mg magnesium daily and think this might be the cause. I have also experienced severe neck pain so I will be cutting right back to around 300 mg daily in divided doses and see what happens.

  9. Hi I have m.e/cfs. I’d heard/researched magnesium can be beneficial for fatigue. I took a 500mg tablet and had terrible stomach cramps and diarrhoea. So I halved the tablet but still reacted badly, I was sick this morning. I’m guessing the dose was way to high and I’m not tolerant of it.

    I feel so ill today feel like I’m having a relapse and the sickness etc has made the m e 10 times worse.

  10. If anyone knows anything non habbit forming minus magnesium to help with chronic Constipation please share .I’m not willing to take any magnesium
    For migraine its too painful.

  11. I’ve had migraines for years I’ve also had chronic Constipation, I recently linked 50% Of my migraines to a “supposedly non habbit forming Mag-O7
    It contains elemental magnesium 1035 mg per capsule and
    Potassium 99mg ” on an average I would take it once a week until I discovered they were actually increasing my migraines.I was taking 4 once a week and Felt horrible the next Within hours of taking I develop neck pain consistent with an on coming migraine.

  12. Wow — I had no idea about the magnesium / nausea connection, but this certainly explains things now that I read this string of responses. I have an auto-immune condition, and am on immunosuppressants, and was told to take Vit D and calcium. I read somewhere (in other words, my doc didn’t prescribe it) that magnesium (250 mg per diem) would help, too. I realize now, after about 2 weeks of starting, that I’ve been feeling pretty darn crappy. I wonder if this is why??? I’ll do some experimenting… thanks!

  13. It is now understood that one of the best ways to ‘take’ magnesium is via oils, sprays or in a bath/footbath, as taking supplements can cause nausea and diarrhea!

    Just Google Magnesium oil or spray and see what pops up!
    Some people make their own using Magnesium Chloride
    Flakes available in stores or on-line.

  14. I am pregnant with twins and was told to take 1000 mg of magnesium a day. Along with a bunch of other supplements. I spread the supplements throughout the day, but as soon as I take the magnesium, it comes up immediately. Miserable!

    1. Liz, that sounds miserable indeed. You might want to try a different kind of magnesium. Some are more tolerable than others. I use MgBright with success. Others find liquid magnesium to be easier on their stomachs. That’s a high dose—you may want to work up to it, rather than start at 1,000 mg. Best of luck finding a solution.

      Take care,

  15. Minerals must be properly balanced in the body. Taking large quantities of just one mineral like magnesium can cause other minerals to be depleted. It’s ill-advised to take large doses or for an extended time something that is not meant to be a mineral supplement. Mylanta is an antacid. Sure it contains magnesium but it isn’t a diet supplement. Certainly after three days of mylanta one would have problems. You need your stomach acid.

    Epsom salts contain magnesium too. If you take epsom salts as a magnesium supplement you’ll likely end up with nausea and diarrhea. It’s not because of the magnesium it’s because magnesium sulfate is a laxative.

    If you are going to supplement a mineral, do it right by taking something formulated as such and properly balanced with other minerals. Magnesium when taken regularly should be combined with at least calcium and zinc and probably iron as well to prevent further imbalances.

    Taking too much vitamin C will also cause nausea. The nausea threshold is different for each person. Taking extra multi-vitamins is not a good plan for increasing the dose of one of the ingredients, as it can cause an excess dose of another ingredient like vit C.

  16. When you overload on one mineral, it can exacerbate a deficiency of another. Women tend to have higher iron needs then men, and low iron can lead to headaches (as well as heart palpitations upon exertion and lack of energy in general). Zinc could be another mineral. Some folks who take a regular multivitamin may get overloaded on Vitamin A or D (esp. D, since some folks just going over the 400IU/day can get a headache). As for Magnesium allergies … you’re not allergic to it. You may be allergic to some unpure form of it, EG: if it was in a green veggie blend of vitamins … you might be allergic to one of the veggies used. People are not allergic to vitamins and minerals which are standard components of the human body, though. However, the Magnesium could have been exactly what you needed in order to take care of some other excess in your system. There may have been a build up of something else, and the extra magnesium gave your body the ability to mobilize it. It’s really hard to say. However, it’s generally a good idea to ramp up slowly, rather than diving in with mega-doses daily. As a side note, food additives can cause migraines in some folks, especially artificial sweeteners, caffeine, monosodium glutamate, etc. Clean out your diet … don’t eat anything unless it comes from the vegetable/fruit and meat aisles at the grocery (IE: basically shop the outer ring of the grocery store and avoid the aisles where all the junk & canned foods are.) Even that’s debateable, though, since they’re now adding stuff to “fresh” meat (EG: pork is now “enhanced” with “solution” for taste these days, a solution which has soy, monosodium glutamate, etc). Cut out sodas, fake sweeteners, and try to eat clean for a while. If artificial sweeteners are the problem, you may get a really bad migraine for a few days from withdrawal as it clears out of your system.

  17. Hi, I know this is an old post, but i did a bit of investigation on my own with magnesium, and what i’ve found is that when i take magnesium, for about two to three days, i suffer from a headache. I think, (1) either i’m allergic to magnesium or (2) it’s just too strong for me. However, the last time i took magnesium, it was in the form of mylanta. Go figure.

  18. Hi Kerrie,

    I’m sorry to hear you had such a reaction to Magnesium. 🙁

    My doctor recommended I begin 250mg of Magnesium 2x a day, along with Riboflavin 400mg once a day (or 200mg 2x a day). He’d also like me to begin Omega 3 fish oil. (Exact recommendation I’m unable to recall at the moment.) I’ve taken Magnesium in the past and didn’t notice much improvement, but I’m willing to try again, along with his other recommendations, so we’ll see what happens.

    Hope you feel better.

  19. Hi Kerrie,

    My neurologist’s office has an infusion center that patients can go to to break the cycle of a horrible migraine.

    They have various medications that are given that are specific to the particular patient. Through trial and error a patient is given what works best for them.

    Well they gave me IV magnesium one time during a treatment and my BP dropped so low, we are talking 30/22. Talk about scary!

    To make a long story short they had to have an ambulance come to the clinic and take me to the hospital because nothing they did at the clinic to raise my BP worked.

    I ended up passing out due to my low BP and the next thing I knew I woke up in the ER.

    They gave me tons of fluids and some other meds the names of which escape me right now but slowly my BP started rising.

    I had to spend the night for observation and was able to go home the next afternoon.

    I realize my reaction to Magnesium was extreem, but you can bet that I will never take it again! I am very wary of it. It is in the hospital computers not to ever give it to me thank goodness!

    So there is my experience with Mag, sorry it was such a novel. Thanks for reading my story.

    I’m glad that you are feeling better now that you have stopped taking it.

    Take Care,

  20. I took magnesium supplements for five months, and I didn’t notice any difference with my migraines. So I stopped taking it. Luckily, I didn’t get any side effects from it.

  21. Hi Kerrie –
    I had nausea from magnesium supplements too. It was just so long ago that I’d forgotten all about it until reading this. I’m so glad you figured out the problem. How frustrating that it did seem to help your head, though. I’ve had to give up helpful medications before, because of side effects – it’s such a bummer.
    Best of luck with the continuing investigation!

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