Hello Bill! Thanks for this question.

Zinc oxide is one of the more commonly used and affordable forms of zinc in supplements, but it is generally considered to have lower bioavailability compared to other forms. Research suggests that chelated forms of zinc, particularly zinc picolinate, zinc citrate, and zinc glycinate, tend to be more readily absorbed by the body. Zinc monomethionine is another well-absorbed form. Zinc sulfate is another common option, though it can sometimes cause more digestive upset than chelated forms.

This matters because a higher milligram amount on a label does not necessarily translate to more zinc actually being used by your body. You may be getting 200% of the daily value on paper, but the actual amount absorbed could be meaningfully less depending on the form.

It’s also valuable to note that zinc absorption decreases with age and can be further reduced on a plant-based diet due to phytates in plant foods binding to zinc and limiting uptake. So the form of zinc in your supplement is worth paying attention to, especially as you get older.

Given that 25 mg is already a relatively high dose, and that long-term high zinc intake can interfere with copper absorption, this is a good conversation to have with your healthcare provider, who can help you assess whether your current supplement is serving you well or whether a different form or dose might be more appropriate for your needs.

I hope this is helpful information! –Ina, Food Revolution Network Team