Quality. We included products that are manufactured by reputable companies that follow current good manufacturing processes (CGMPs) set by the Food and Drug Administration, use high quality ingredients, and are tested for purity and quality. One meta-analysis from 2017 concluded that lozenges containing zinc acetate were effective at shortening the duration of cold symptoms by nearly 33% ( 8). Ward, J. D.; Spears, J. W. (1997). "Long-Term Effects of Consumption of Low-Copper Diets with or Without Supplemental Molybdenum on Copper Status, Performance, and Carcass Characteristics of Cattle". Journal of Animal Science. 75 (11): 3057–3065. doi: 10.2527/1997.75113057x. PMID 9374323.

In fact, one review found that consuming a dosage of 80–92 mg of zinc from zinc lozenges per day helped reduce the duration of the common cold by up to 33% ( 8).The company’s Zinc Drink liquid supplement contains only water and 15 mg of zinc sulfate per serving, making it free of any additives and preservatives.

The recommended daily allowance (RDA) is around 900 micrograms (mcg) a day for adolescents and adults. Before buying any supplement, it’s important to research high quality, trustworthy brands to ensure both safety and quality. For certain populations, such as older adults and those with stomach issues, chelated minerals are a suitable alternative to regular minerals. However, for most healthy adults, there’s no need to choose one over the other. Multiple ways of differentiating the geometric isomers exist, an easily accessible one being IR spectroscopy with the characteristic number of C–N, C–O, and Cu II–N identifying the ligand configuration. Crystal appearance may also be of some value for isomer indication, though the ultimate diagnostic technique is X-ray crystallography. [1]

Chen, T., Liang, B., Xin, X., Solid State Synthesis of the cis and trans-Isomers of Bis(Glycineto)Copper(II) and their Formation Pathway, J. Phys. Chem. Solids, 58, 951-955, 1997. A copper deficiency can have negative effects on health, but it is rare in healthy people who follow a balanced diet. Appendix 7. Nutritional goals for age-sex groups based on dietary reference intakes and dietary guidelines recommendations. (2015) More research is needed on how marginal copper deficiency may affect bone health, and how copper supplementation might help prevent and manage osteoporosis. Collagen production