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Zinc (as Monomethionine and Aspartate)

Also known as: Zinc monomethionine aspartate, Zn-monomethionine aspartate, Zinc aspartate, Zn-aspartate, ZMA, Zinc monomethionine, Zinc aspartate, Zinc Monomethionine Aspartate

Overview

Zinc monomethionine aspartate is a chelated form of zinc, combining zinc with the amino acids methionine and aspartate to potentially enhance bioavailability. It is often found in supplements marketed for immune support, athletic performance, and muscle recovery, most notably in ZMA (a combination of zinc monomethionine aspartate, magnesium aspartate, and vitamin B6). Natural sources of zinc include meat, shellfish, legumes, seeds, and nuts. While zinc supplementation is well-researched for addressing deficiencies and supporting immune function, evidence for performance enhancement, particularly with zinc monomethionine/aspartate specifically, is less conclusive, especially in individuals who are not zinc-deficient. The chelated form is believed to offer better absorption compared to inorganic zinc salts. Research on this specific chelate is moderate, with studies showing mixed results, particularly in athletic populations.

Benefits

Zinc monomethionine aspartate primarily benefits individuals with zinc deficiencies by improving immune function and wound healing. Supplementation may also restore normal testosterone and IGF-1 levels in deficient individuals. In athletes, ZMA supplementation has shown mixed results. One study indicated an increase in counter-movement jump height after acute dosing, but no effect on sleep or cognitive performance in healthy males. Secondary benefits may include support for muscle recovery and anabolic hormone profiles in athletes with deficiencies. Overall, the benefits are most pronounced in those with zinc or magnesium deficiencies, with limited evidence for benefits in well-nourished athletes. Effect sizes for performance are generally small to moderate in deficient populations and minimal or non-significant in non-deficient groups. Benefits related to hormone profiles may require weeks of supplementation.

How it works

Zinc monomethionine aspartate works primarily through zinc's role as a cofactor for over 300 enzymes involved in various biological processes, including DNA synthesis, immune function, protein synthesis, and hormone regulation. The methionine and aspartate components are believed to enhance zinc absorption and utilization within the body. Zinc supports the immune, endocrine, and musculoskeletal systems by interacting with enzymes, transcription factors, and hormone receptors. Chelated forms of zinc, like monomethionine and aspartate, may offer improved bioavailability compared to inorganic zinc salts, facilitating better absorption and utilization of zinc within the body.

Side effects

Zinc monomethionine aspartate is generally safe at recommended doses, but high doses can lead to adverse effects. Common side effects include gastrointestinal upset, such as nausea and diarrhea. Less common side effects include headache and a metallic taste. Rare side effects, particularly with chronic high-dose use, include copper deficiency. Zinc can interact with certain antibiotics, such as quinolones and tetracyclines, reducing their absorption. It may also interact with diuretics and immunosuppressants. Contraindications include severe renal impairment and hypersensitivity to the ingredients. Pregnant and lactating women should avoid high doses, and individuals with chronic illnesses or those on multiple medications should be monitored closely. It is important to adhere to recommended dosages to minimize the risk of adverse effects.

Dosage

The minimum effective dose of elemental zinc is 10–15 mg per day for addressing deficiency. Optimal dosage ranges are typically between 15–40 mg of elemental zinc per day for most adults, with higher doses only under medical supervision. The maximum safe dose is 40 mg/day for adults for long-term use, while acute toxicity is possible above 100 mg/day. It is best taken with food to reduce gastrointestinal upset, and evening dosing is common in ZMA formulations. Chelated forms like monomethionine and aspartate are preferred for their potential bioavailability benefits. Absorption can be enhanced by protein-rich meals but inhibited by phytates found in grains and legumes. Vitamin B6 and magnesium are often included in ZMA formulations for synergistic effects.

FAQs

Who benefits most from zinc monomethionine/aspartate?

Individuals with zinc deficiencies or athletes with suspected deficiencies are most likely to benefit. There is limited evidence of performance benefits in well-nourished individuals.

What are the potential side effects?

Common side effects include gastrointestinal upset. Avoid high doses unless medically indicated and monitor for any adverse reactions.

When and how should I take it?

Take with food, preferably in the evening if part of a ZMA supplement, to enhance absorption and minimize gastrointestinal discomfort.

Is zinc monomethionine/aspartate a muscle-building supplement?

It is not a direct muscle-building supplement. Benefits are primarily seen in correcting deficiencies and supporting immune function, not in enhancing muscle growth in non-deficient individuals.

What results can I expect?

Improved immune function and hormone profiles may be seen in deficient individuals. Minimal or no performance enhancement is expected in non-deficient populations.

Research Sources

  • https://pubmed.ncbi.nlm.nih.gov/39125347/ – This study investigated the effects of ZMA supplementation on recreationally trained males. The results indicated that ZMA improved counter-movement jump height compared to placebo, but not compared to a no-pill control. The study found no significant effects on sleep or cognitive performance, suggesting limited benefits in healthy, non-deficient individuals.
  • https://www.mdpi.com/2072-6643/16/15/2466 – This is a recent article, but it does not directly evaluate zinc monomethionine aspartate. Further information is needed to summarize its findings. The article's relevance to the specific supplement needs to be established before a summary can be provided.
  • https://exrx.net/Nutrition/Supplements/ZMA – This website provides general information about ZMA, highlighting its use as a supplement for athletes. It suggests that ZMA may help improve recovery and hormone levels, but also notes that research findings are mixed, and benefits are most likely in individuals with zinc or magnesium deficiencies. The site emphasizes the importance of adequate zinc and magnesium intake for overall health and athletic performance.
  • https://www.medicinenet.com/what_is_zma_and_is_it_worth_taking/article.htm – This article discusses ZMA and its potential benefits, noting that it is often marketed to athletes for muscle growth and recovery. It explains that ZMA contains zinc, magnesium, and vitamin B6, all of which play important roles in bodily functions. The article also cautions that while ZMA may be beneficial for those deficient in these nutrients, there is limited evidence to support its use for enhancing performance in well-nourished individuals.
  • https://asep.org/asep/asep/BrillaV2.PDF – This study examined the effects of ZMA supplementation on varsity football players. The results indicated that the ZMA group experienced increased total testosterone, free testosterone, and IGF-1 levels compared to the placebo group. These findings suggest that ZMA may have a positive impact on anabolic hormone profiles in athletes, although the study's limitations, such as small sample size and attrition, should be considered.