Can You Take Zinc and Magnesium Together?

Yes. Zinc and magnesium can be taken together at normal doses. The only human evidence of interference came from zinc intakes of 53 to 142 mg a day^{1, 2}, above the 40 mg adult upper limit³.

That interference ran one way: very high-dose zinc lowered magnesium balance. We found no human trial in which magnesium lowered zinc absorption. The pairings that need care are either mineral with certain medications. Calcium is the other mineral often discussed with zinc: see our guide to zinc, magnesium and calcium.

Because two metabolic studies found that high zinc intakes lowered magnesium absorption or balance. Both used zinc above the 40 mg adult upper limit³.

• 142 mg of zinc a day: in three groups of adult men given zinc sulfate, pooled magnesium absorption and magnesium balance fell significantly. By group, the fall appeared only in the men eating 500 mg of calcium a day¹. NIH calls these very high doses³.
• 53 mg of zinc a day for 90 days: in 25 postmenopausal women, a diet supplemented to this "moderately high" level raised magnesium losses in stool and urine and lowered magnesium balance, compared with a 3 mg diet. Absorption was not measured. The authors called for study in people who eat less magnesium than recommended².

Neither study used a dose near the zinc RDA of 8 mg for women or 11 mg for men³. We found no human trial showing that the two compete for absorption at ordinary doses: none showed magnesium lowering zinc absorption, and none measured the absorption of the two together.

Either works for most adults. No trial compared the two timings, so the choice rests on stomach tolerance and on what else you take.

• Zinc with food: in 12 volunteers, absorption of 15 mg of zinc from a multimineral supplement was estimated at 38% fasting and 10% with a light meal⁴. In 4 adults given a zinc-free breakfast, the fractional absorption of 3 mg and 5 mg doses was lower than for 1 mg, while fasting absorption held steady up to 5 mg⁵. A review of zinc homeostasis found supplements are not absorbed differently from meals that lack inhibitors such as phytate⁶. What the meal contains matters.
• Magnesium absorption and tolerance: about 30% to 40% of the magnesium in food and drink is absorbed. High doses from supplements often cause diarrhea, nausea and abdominal cramping⁷.

NIH lists nausea among the effects of high zinc intakes³. If zinc upsets your stomach, a meal is the trade-off: expect lower absorption (38% fasting against 10% with a light meal above)⁴. Do not raise the dose to compensate.

Can you take zinc and magnesium together on an empty stomach?

No trial tested the pair fasting. Zinc is absorbed better without food, so the trade is absorption against comfort. Nausea is a listed effect of high zinc intakes³.

Does the form of zinc or magnesium matter?

Somewhat. In 15 adults given 10 mg of zinc without food, absorption was 61.3% from citrate and 60.9% from gluconate, against 49.9% from oxide⁸. NIH notes that small studies found magnesium aspartate, citrate, lactate and chloride absorbed more completely than oxide and sulfate⁷. The forms most often reported to cause diarrhea are carbonate, chloride, gluconate and oxide⁷.

We found no study of magnesium glycinate taken with zinc, so any claim that this form changes the interaction is untested.

Yes within the daily limits below, but the evidence that the pair improves sleep is thin. Most trials used zinc magnesium aspartate (ZMA), a combined product.

• Healthy men, no benefit: two nights of ZMA taken before bed did not change sleep in 19 recreationally trained men with adequate diets⁹. In 16 trained men limited to 4 hours of sleep, ZMA had no effect on sleep or on morning weightlifting¹⁰.
• Healthy men, less sleep: in 69 men with 4 or 8 hours of sleep opportunity, ZMA did not change morning Stroop test scores but reduced total sleep time by about 0.46 hours, and by about 0.94 hours in the 8-hour group¹¹.
• Older adults with insomnia, but with melatonin: in 43 care-home residents, a blend of 5 mg melatonin, 225 mg magnesium and 11.25 mg zinc taken an hour before bed for 8 weeks improved Pittsburgh Sleep Quality Index scores by 6.8 points more than placebo¹². Melatonin was in the blend, so the minerals cannot take the credit.

Each mineral has its own sleep evidence. A meta-analysis of 3 trials in 151 older adults found sleep onset 17.36 minutes shorter with magnesium, rated low to very low quality¹³. In 155 adults with poor sleep, 250 mg of magnesium as bisglycinate lowered Insomnia Severity Index scores by 3.9 points against 2.3 for placebo at 4 weeks, a small effect¹⁴. A systematic review of 8 zinc trials, with doses of 10 to 73.3 mg a day, found most pointed to better sleep quality in adults, with no consensus¹⁵.

No trial has tested zinc plus magnesium alone against placebo in people with poor sleep. See magnesium for sleep quality and when to take magnesium for timing.

Not in the ZMA trials, which found no testosterone or strength benefit in trained men.

• 42 resistance-trained men, 8 weeks: ZMA taken 30 to 60 minutes before sleep did not change anabolic or catabolic hormones, body composition, strength or endurance compared with placebo. Serum zinc rose 11% to 17%, not significantly¹⁶.
• 14 exercising men: ZMA raised serum zinc but not total or free testosterone, in men whose diets already provided 11.9 to 23.2 mg of zinc a day¹⁷.
• Magnesium alone: a small study giving 10 mg of magnesium per kilogram of body weight for 4 weeks found higher free and total testosterone in athletes and sedentary men¹⁸. That dose is about 700 mg for a 70 kg adult, twice the 350 mg supplemental limit⁷, so do not copy it. One small study is not enough to rely on.

See zinc for testosterone support and magnesium for testosterone support for the full evidence.

NIH names a short list of drug interactions, plus a long-term mineral effect:

• Quinolone and tetracycline antibiotics: zinc could inhibit absorption of both the zinc and the antibiotic if taken at the same time³.
• Penicillamine: zinc can reduce its absorption and action³.
• Thiazide diuretics: these raise urinary zinc excretion and lower serum zinc³.
• Copper: 50 mg of zinc or more over weeks can inhibit copper absorption, reduce immune function and lower HDL cholesterol³.

Our guide on what not to take with zinc covers the rest, including calcium and iron.

Three groups, according to NIH and a recent trial:

• Tetracycline and quinolone antibiotics: take the antibiotic at least 2 hours before or 4 to 6 hours after magnesium, because it forms insoluble complexes⁷.
• Oral bisphosphonates: take magnesium at least 2 hours before or after⁷.
• Levothyroxine: see the next question.

More medicines are in our antibiotics and supplements and what not to take with magnesium guides. Medicines can also change magnesium levels. Loop and thiazide diuretics increase urinary magnesium loss, and proton pump inhibitors taken for over a year can cause low magnesium⁷.

Does magnesium affect TSH levels?

Magnesium can lower levothyroxine absorption, which is what would push TSH up. In 15 healthy adults, magnesium aspartate cut thyroxine exposure by 12%, and magnesium citrate by 7%, which was not significant¹⁹. The trial measured thyroxine over 6 hours and did not follow TSH. Its authors advised hypothyroid patients to separate levothyroxine from magnesium, especially if TSH must stay in a narrow range¹⁹. The trial did not test a specific gap, so ask your pharmacist.

Adults should stay under the upper limits: 40 mg of zinc from all sources and 350 mg of magnesium from supplements and medicines. Magnesium in food does not count toward the limit^{3, 7}.

• Zinc RDA: 11 mg for men and 8 mg for women aged 19 and over; 11 mg in pregnancy and 12 mg while breastfeeding at 19 and over³.
• Magnesium RDA: 310 to 420 mg for adults, depending on age and sex⁷.
• Children and teens: the supplemental magnesium limit is 65 mg at ages 1 to 3 and 110 mg at ages 4 to 8⁷. Zinc limits run from 4 mg in infants to 34 mg at ages 14 to 18, including in pregnancy and lactation³.

A 2023 perspective reviewed 10 studies and found 7, at 128 to 1,200 mg of magnesium a day, showed no significant difference in diarrhea from placebo. Its authors argued the 350 mg limit should be re-evaluated²⁰. The limit still stands in NIH guidance⁷.

Yes if you have kidney disease, a gut condition or take any of the medications above. The risk of magnesium toxicity rises with impaired kidney function, because the kidneys remove less of the excess⁷.

High doses of magnesium often cause diarrhea⁷. NIH notes that chronic diarrhea and fat malabsorption in Crohn's disease and celiac disease can deplete magnesium over time⁷, and that zinc inadequacy is common in inflammatory bowel disease³. We found no trial of magnesium supplements in colitis; see the questions below.

Oysters are highest in zinc by a wide margin. Pumpkin seeds top the NIH magnesium table and also supply some zinc. NIH lists these amounts per serving^{3, 7}:

• Oysters, Pacific, cooked, 3 ounces: 28.2 mg zinc (256% of the Daily Value)³.
• Beef, bottom sirloin, roasted, 3 ounces: 3.8 mg zinc (35%)³.
• Pumpkin seeds, roasted, 1 ounce: 2.2 mg zinc (20%) and 156 mg magnesium (37%)^{3, 7}.
• Chia seeds, 1 ounce: 111 mg magnesium (26%)⁷.
• Almonds, dry roasted, 1 ounce: 80 mg magnesium (19%)⁷.
• Spinach, boiled, half a cup: 78 mg magnesium (19%)⁷.

Plant foods absorb less zinc because of phytate: the share absorbed ranges from 5% to over 50%, depending on how much plant food is in the diet³. See foods high in zinc and magnesium-rich foods.

The signs are broad, so they cannot confirm a deficiency on their own. NIH describes them by age, not as a fixed list³.

• Low zinc: in children it delays growth and causes diarrhea and hair loss; in older adults it can alter cognitive and psychological function³.
• Low magnesium: early signs are loss of appetite, nausea, vomiting, fatigue and weakness. Later come numbness, muscle cramps, seizures and abnormal heart rhythms⁷.

Intake is often short. A national survey found 48% of Americans ate less magnesium than their estimated average requirement⁷. Higher-risk groups for zinc include people with gut disorders or bariatric surgery, vegetarians and vegans, pregnant or lactating women, and people with alcohol use disorder³. Magnesium is not evaluated in routine electrolyte testing, and serum levels do not accurately reflect total body magnesium, so a normal result does not rule out low intake⁷. Read about zinc deficiency and magnesium deficiency.

This is a decision rule, not a tested schedule. No trial compared times of day for the pair.

• Healthy adult, no medications: take both with dinner. Bedtime works too, but no trial shows it improves sleep. Keep zinc under 40 mg and supplemental magnesium under 350 mg^{3, 7}.
• Zinc upsets your stomach: take zinc with a meal and accept lower absorption⁴.
• On levothyroxine: separate magnesium from it and ask your pharmacist for the gap¹⁹.
• On a tetracycline or quinolone antibiotic: take it at least 2 hours before, or 4 to 6 hours after, magnesium. Do the same for zinc^{7, 3}.
• Also taking calcium: read our zinc, magnesium and calcium guide.
• Also taking vitamin D: see magnesium with vitamin D.

Supplements in this guide

• Magnesium
• Zinc

We searched PubMed through Firecrawl's research index for human studies of zinc and magnesium interactions, ZMA, zinc and magnesium absorption, and sleep. We also read the NIH Office of Dietary Supplements fact sheets for zinc and magnesium. We cited 18 journal articles and 2 NIH fact sheets, prioritizing controlled and metabolic studies in adults. We read abstracts, not full texts, so trial doses that abstracts omit are left out. We found no human trial of normal-dose zinc and magnesium absorbed together, and the interference data come from small, decades-old metabolic studies. Last checked November 2, 2026.

1. Spencer H, et al. Inhibitory effects of zinc on magnesium balance and magnesium absorption in man. J Am Coll Nutr. 1994;13(5):479-84. doi:10.1080/07315724.1994.10718438
2. Nielsen FH, et al. A moderately high intake compared to a low intake of zinc depresses magnesium balance and alters indices of bone turnover in postmenopausal women. Eur J Clin Nutr. 2004;58(5):703-10. doi:10.1038/sj.ejcn.1601867
3. National Institutes of Health, Office of Dietary Supplements. Zinc: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/
4. Sandström B, et al. Retention of selenium (75Se), Zinc (65Zn) and manganese (54Mn) in humans after intake of a labelled vitamin and mineral supplement. J Trace Elem Electrolytes Health Dis. 1987;1(1):33-8. https://pubmed.ncbi.nlm.nih.gov/2856562/
5. Sian L, et al. Influence of a meal and incremental doses of zinc on changes in zinc absorption. Am J Clin Nutr. 1993;58(4):533-6. doi:10.1093/ajcn/58.4.533
6. Hambidge KM, et al. Zinc bioavailability and homeostasis. Am J Clin Nutr. 2010;91(5):1478S-1483S. doi:10.3945/ajcn.2010.28674I
7. National Institutes of Health, Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/
8. Wegmüller R, et al. Zinc absorption by young adults from supplemental zinc citrate is comparable with that from zinc gluconate and higher than from zinc oxide. J Nutr. 2014;144(2):132-6. doi:10.3945/jn.113.181487
9. Edwards BJ, et al. Effects of an Acute Dose of Zinc Monomethionine Asparate and Magnesium Asparate (ZMA) on Subsequent Sleep and Next-Day Morning Performance (Countermovement Jumps, Repeated Sprints and Stroop Test). Nutrients. 2024;16(15). doi:10.3390/nu16152466
10. Gallagher C, et al. Effects of Supplementing Zinc Magnesium Aspartate on Sleep Quality and Submaximal Weightlifting Performance, following Two Consecutive Nights of Partial Sleep Deprivation. Nutrients. 2024;16(2). doi:10.3390/nu16020251
11. Edwards BJ, et al. In Males with Adequate Dietary Needs Who Present No Sleep Disturbances, Is an Acute Intake of Zinc Magnesium Aspartate, Following Either Two Consecutive Nights of 8 or 4 h of Sleep Deprivation, Beneficial for Sleep and Morning Stroop Interference Performance?. Behav Sci (Basel). 2024;14(7). doi:10.3390/bs14070622
12. Rondanelli M, et al. The effect of melatonin, magnesium, and zinc on primary insomnia in long-term care facility residents in Italy: a double-blind, placebo-controlled clinical trial. J Am Geriatr Soc. 2011;59(1):82-90. doi:10.1111/j.1532-5415.2010.03232.x Our study summary.
13. Mah J, et al. Oral magnesium supplementation for insomnia in older adults: a Systematic Review & Meta-Analysis. BMC Complement Med Ther. 2021;21(1):125. doi:10.1186/s12906-021-03297-z Our study summary.
14. Schuster J, et al. Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial. Nat Sci Sleep. 2025;17:2027-2040. doi:10.2147/NSS.S524348 Our study summary.
15. Jazinaki MS, et al. Effects of zinc supplementation on sleep quality in humans: A systematic review of randomized controlled trials. Health Sci Rep. 2024;7(10):e70019. doi:10.1002/hsr2.70019
16. Wilborn CD, et al. Effects of Zinc Magnesium Aspartate (ZMA) Supplementation on Training Adaptations and Markers of Anabolism and Catabolism. J Int Soc Sports Nutr. 2004;1(2):12-20. doi:10.1186/1550-2783-1-2-12
17. Koehler K, et al. Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement. Eur J Clin Nutr. 2009;63(1):65-70. doi:10.1038/sj.ejcn.1602899
18. Cinar V, et al. Effects of magnesium supplementation on testosterone levels of athletes and sedentary subjects at rest and after exhaustion. Biol Trace Elem Res. 2011;140(1):18-23. doi:10.1007/s12011-010-8676-3
19. Attinger MC, et al. Single Center, Open-Label, Randomized Crossover Trial on Drug-Drug Interactions of Levothyroxine/Magnesium-Citrate and Levothyroxine/Magnesium-Aspartate in Healthy Subjects-The ThyroMag Trial. Clin Transl Sci. 2025;18(11):e70409. doi:10.1111/cts.70409
20. Costello R, et al. Perspective: Call for Re-evaluation of the Tolerable Upper Intake Level for Magnesium Supplementation in Adults. Adv Nutr. 2023;14(5):973-982. doi:10.1016/j.advnut.2023.06.008