The right amount of magnesium citrate depends on what you're using it for and how much magnesium you already get from food. Here's how to think about the numbers, including the upper limit most people don't know about.
Written by Vita Globe Editorial Team | Reviewed against NIH Office of Dietary Supplements guidance and FDA drug labeling
How much magnesium citrate should I take?
For a daily supplement, think about your total magnesium needs. The adult RDA is 400 to 420 mg for men and 310 to 320 mg for women, from all sources combined[1]. The upper limit for magnesium from supplements and medications is 350 mg a day for adults, not counting food[1]. Liquid magnesium citrate laxatives are dosed very differently: 6.5 to 10 fl oz, or roughly 1,900 to 2,900 mg of magnesium, for occasional, short-term use only[2].
Caveat: These are general numbers for healthy adults. Kidney disease, pregnancy and certain medications change the picture, so check with your healthcare provider.
Sources: NIH ODS · DailyMed label · Verified 2026-09-27
In this article
How much magnesium do adults need each day?
The NIH sets these Recommended Dietary Allowances (RDAs), which include magnesium from food, drinks, supplements and medications[1]:
| Age | Men | Women | Pregnancy | Lactation |
|---|---|---|---|---|
| 19–30 years | 400 mg | 310 mg | 350 mg | 310 mg |
| 31–50 years | 420 mg | 320 mg | 360 mg | 320 mg |
| 51+ years | 420 mg | 320 mg | – | – |
The Daily Value you see on labels is 420 mg for adults and children 4 and older[1].
What's the upper limit for magnesium supplements?
For adults, the Tolerable Upper Intake Level (UL) for supplemental magnesium is 350 mg a day[1]. It's easy to misread, so here's what it means:
- The UL covers magnesium from supplements and medications only. Magnesium naturally found in food and drinks doesn't count toward it[1].
- It's lower than the RDA because it isn't a target. It's a ceiling for the supplemental portion.
- Going over it often causes diarrhea, which can come with nausea and abdominal cramping[1].
Much larger amounts are a different level of risk. Very large doses of magnesium-containing laxatives and antacids, typically more than 5,000 mg a day, have been linked to magnesium toxicity, especially when kidney function is impaired[1].
How do you figure out how much to take?
Start with food. Pumpkin seeds, chia seeds, almonds, spinach, cashews, beans and whole grains are all good sources (see our list of foods high in magnesium). Researchers have argued that suboptimal magnesium status is common in the U.S. and may be underappreciated[3], and about 48% of Americans fall short of the estimated average requirement from food alone[1].
A supplement makes sense as a gap-filler, not a replacement for a decent diet. For most healthy adults, a modest supplement that keeps total supplemental magnesium below 350 mg a day is a reasonable approach. Follow the suggested use on your product's label, and don't stack several magnesium products (a multivitamin, a sleep blend and a separate magnesium) without adding them up.
The honest summary
- Your RDA (310–420 mg) counts everything you eat and take.
- Supplements and medications together should stay at or under 350 mg a day unless a clinician advises otherwise.
- More isn't better. Extra magnesium beyond your needs mostly shows up as loose stools.
- Laxative doses are a separate, short-term use.
How much magnesium citrate is used for constipation?
The liquid laxative label for adults and children 12 and older says 6.5 to 10 fl oz, with a maximum of 10 fl oz in 24 hours. Each fluid ounce contains 1.745 g of magnesium citrate, which provides 290 mg of magnesium[2]. That works out to roughly 1,900 to 2,900 mg of magnesium per dose.
Notice the label lists two numbers. The compound weight (1.745 g of magnesium citrate) is much bigger than the magnesium it provides (290 mg). When you compare products, always compare magnesium to magnesium.
MedlinePlus advises not taking magnesium citrate as a laxative for more than 1 week unless your doctor tells you to, and taking the liquid with a full 8 oz glass of liquid[4].
Does the form of magnesium change the dose?
The RDA and UL are given as milligrams of magnesium, whatever the form. But form can affect how much you absorb. Magnesium citrate was more bioavailable than magnesium oxide in a direct comparison[5]. If you're weighing citrate against glycinate, see our post on magnesium glycinate vs. citrate.
Our option
Vita Globe Magnesium Citrate Gummies
Our gummy is designed as a modest daily top-up, not a high-dose product. The product is labeled 70 mg and comes 60 gummies to a bottle; the suggested use is 2 gummies once daily. The gummies are raspberry-flavored, vegan, gluten-free and non-GMO, made without artificial colors or flavors, and tested by an independent third-party lab. Check the Supplement Facts panel and count it toward your 350 mg supplemental limit if you take other magnesium products.
Frequently asked questions
Is 70 mg of magnesium enough?
It depends on your diet. 70 mg is a modest top-up. If you already eat plenty of magnesium-rich foods, that may be all you need; if your diet is low, talk to a professional about your total intake. The adult RDA is 310–420 mg from all sources[1].
Is 400 mg of magnesium citrate too much?
400 mg of supplemental magnesium is above the adult UL of 350 mg a day[1]. Some clinicians recommend higher doses for specific reasons, but that should be under their guidance.
How much magnesium citrate should I take for constipation?
For the liquid laxative, follow the label: for adults, 6.5 to 10 fl oz, no more than 10 fl oz in 24 hours[2], and not for more than 1 week without a doctor's advice[4].
Does magnesium from food count toward the upper limit?
No. The 350 mg UL applies only to supplements and medications[1].
Can I split my magnesium dose?
Generally yes, as long as you follow your product's directions. What matters most is your total supplemental amount per day.
Sources
- Office of Dietary Supplements, National Institutes of Health. Magnesium: Fact Sheet for Health Professionals. Updated January 6, 2026. ods.od.nih.gov
- DailyMed, U.S. National Library of Medicine. Magnesium Citrate Oral Solution (lemon), Shield Pharmaceuticals Corp. Drug Facts label. dailymed.nlm.nih.gov
- Rosanoff A, Weaver CM, Rude RK. Suboptimal magnesium status in the United States: are the health consequences underestimated? Nutr Rev. 2012;70(3):153-164. doi:10.1111/j.1753-4887.2011.00465.x
- MedlinePlus, U.S. National Library of Medicine. Magnesium Citrate (drug information). Last revised April 15, 2019. medlineplus.gov
- Lindberg JS, Zobitz MM, Poindexter JR, Pak CY. Magnesium bioavailability from magnesium citrate and magnesium oxide. J Am Coll Nutr. 1990;9(1):48-55. doi:10.1080/07315724.1990.10720349
About the Vita Globe Editorial Team
The Vita Globe Editorial Team researches and writes our wellness content, working from peer-reviewed research, systematic reviews and guidance from bodies such as the NIH and the FDA. We cite our sources inline and update articles when the evidence changes.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and is not a substitute for medical advice. Talk to your healthcare provider before starting any new supplement, particularly if you are pregnant, nursing, taking medication, or caring for a child.
