Yes, you can take magnesium and zinc together safely — but there are absorption considerations. At very high supplemental zinc doses (>142 mg/day, far above typical supplementation), zinc can reduce magnesium absorption. At normal supplemental doses (zinc 15–30 mg, magnesium 200–400 mg), the interaction is minimal and taking them together is acceptable. For maximum absorption of each, taking them 2 hours apart or with food is a simple way to mitigate any minor competitive absorption.
Key Facts at a Glance
| Safe to take together? | Yes, at standard doses |
| Zinc UL (upper limit) | 40 mg/day from all sources |
| Magnesium UL | 350 mg/day supplemental (no UL for food) |
| Interaction threshold | >142 mg zinc/day reduces Mg absorption |
| Best form for combined use | Zinc picolinate + magnesium glycinate |
| Key concern | High zinc depletes copper, not magnesium |
Do Magnesium and Zinc Compete for Absorption?
In theory, magnesium and zinc compete for some of the same intestinal transporters (particularly the divalent metal transporter DMT-1). However, this competition is only clinically significant at very high supplemental zinc doses. A key study by Solomons et al. found that zinc at 142 mg/day (far higher than typical supplementation of 15–30 mg) significantly reduced magnesium absorption. At the zinc doses in standard supplements (15–30 mg), the competitive effect on magnesium absorption is minimal and unlikely to be clinically meaningful.
The Real Concern: Zinc and Copper Depletion
The more important nutrient interaction with zinc is not magnesium — it is copper. Zinc and copper share the same intestinal transporter (metallothionein). Chronically taking more than 30 mg/day zinc without copper supplementation can cause copper deficiency, which manifests as anaemia, neurological symptoms, and immune impairment. If supplementing with more than 30 mg/day zinc, always include 1–2 mg copper. Magnesium does not have this depletion concern with zinc.
Can You Take Magnesium and Zinc in the Same Supplement?
Yes — combined magnesium-zinc supplements are widely available and commonly used. The ZMA (zinc, magnesium aspartate) formula popular among athletes has been studied in multiple RCTs at combined zinc (30 mg) + magnesium (450 mg) doses with no significant absorption interference reported. Taking a combined supplement with food further reduces any theoretical competitive absorption concerns.
Optimal Timing for Magnesium and Zinc
For maximum absorption of both: take with food (reduces GI side effects and improves absorption of both), and if using therapeutic-range doses of both, taking them at different times of day (e.g., zinc in the morning, magnesium in the evening) provides theoretical benefit. This is particularly relevant if either dose is at the higher end — zinc 30 mg+ or magnesium 400 mg+. Many people simply take both together with their largest meal and achieve good results. The evening timing of magnesium glycinate (for sleep benefits) naturally separates it from morning zinc anyway.
Best Forms When Taking Both
For zinc: picolinate or bisglycinate — both highly bioavailable, gentle on the stomach. For magnesium: glycinate for sleep/evening use, or malate for daytime/energy use. Avoid zinc oxide (poorly absorbed) and magnesium oxide (only 4% bioavailability). These chelated forms use different absorption pathways from ionic forms and are less susceptible to competitive absorption.
ZMA Stack — Does It Work?
ZMA (Zinc Monomethionine/Aspartate, Magnesium Aspartate, and Vitamin B6) is a popular combination supplement claiming muscle recovery and testosterone benefits. The original Brilla & Haff (2000) study showed promising testosterone and strength results in football players, but subsequent independent RCTs have had mixed findings. The combination is safe, both nutrients support testosterone production, and ZMA's effect is likely most pronounced in athletes with zinc or magnesium deficiency from sweat losses.
Frequently Asked Questions
Clinical References
- Solomons NW et al. (1983). J Nutr. Studies on the bioavailability of zinc in humans: effects of magnesium. → Source
- Brilla LR & Haff V. (2000). J Exerc Physiol Online. Effect of a novel zinc-magnesium formulation on hormones and strength. → Source
- NIH Office of Dietary Supplements. Zinc Fact Sheet. → Source
- NIH Office of Dietary Supplements. Magnesium Fact Sheet. → Source