There are many different forms of zinc out there, delivered via complexes (salts and chelates). These specific forms include zinc sulfate, oxide, gluconate, acetate, picolinate, citrate, acetate, glycerate, and monomethionine.
Amino acid chelate forms of this mineral (e.g., zinc bisglycinate chelate) are unique, and research shows they’re gentle, premium, and well-absorbed forms of zinc.
While there aren’t plentiful side-by-side clinical trials in humans, to inform bioavailability of different forms of this mineral, a few do exist. For example, zinc oxide absorption has been shown to be lower than zinc citrate and gluconate forms. And zinc bisglycinate has been shown to have superior absorption than zinc gluconate.
In addition to choosing the right form of zinc, dose is important. Taking too much can interfere with another essential mineral: copper. “Zinc reduces the amount of copper the body is able to absorb, so high doses of zinc can result in copper deficiency,” explains Ivanir.
Specifically, total daily intakes (i.e., food plus supplements) of zinc greater than 60 milligrams, over time, have been tied to copper deficiency.
Experts also agree that when choosing a supplement, make sure it’s tested for purity and potency.