Zinc basics

Zinc, the second-most abundant trace mineral in the body (after iron), is involved in more than 200 enzymatic reactions and plays a key role in genetic expression, cell division, and growth. Zinc is an essential mineral, which means your body doesn’t make it, so it must be obtained from the diet or supplementation. In most diets, zinc comes from red meat, poultry, and oysters, with lesser amounts coming from beans and nuts. Oysters are the highest food source of zinc – 74 mg per 3-ounce serving – which is almost five times its Recommended Daily Value (RDA).

Who is susceptible to a zinc deficiency?

Populations particularly susceptible to a zinc deficiency are athletes who engage in prolonged activity and lose zinc in sweat, vegans or vegetarians who have low dietary intakes, the elderly due to decreased intake and poor absorption, teenagers because of poor diet, and immune-compromised individuals and burn victims due to increased need.

Why is zinc important for optimal health?

Zinc supplementation can increase general wellness, as well as have a beneficial impact on immune health, skin and connective tissue, growth in children, reproductive health, and nerve and eye health.* 

The prostate gland in men contains the highest amount of zinc of any soft tissue. Adequate zinc levels support prostate health and the body's normal production of testosterone.*  

The skin has the third highest amount of zinc of the various organs in the body. Because of zinc’s beneficial effect on immune support, collagen synthesis, and its natural restorative activity, zinc plays an important role in wound healing.*

Zinc and immune support

Perhaps most important is zinc’s role in the function of your immune system.* There is a reason to reach for a zinc lozenge when you have a sore throat. That’s because zinc helps regulate immune function, exhibits antioxidant activity, and helps maintain a balanced inflammatory response in your immune system.*1 Your immune system needs zinc to function properly.* In fact, it seems every immunological event is influenced by zinc, making the immune system especially susceptible to changes in zinc level.*

A zinc deficiency can depress your body's immune response, which reduces the ability to eliminate pathogens, mount a response against threats, and produce antibodies.* The antioxidant properties of zinc mitigate oxidative stress – a process that damages cells and tissues, particularly when a person has an infection.*

A study of immune function in the elderly found that even a marginal zinc deficiency in this population adversely impacts immune function and that zinc supplementation promotes a healthy immune response.*2

What form of zinc is best?

When it comes to taking supplemental zinc, there are several things to consider. The primary objective is to absorb the greatest amount of zinc from the fewest number of capsules and without side effects. So, how is this best accomplished?

The form of the mineral – including the compound it is bound to – matters. One factor that is always an issue when supplementing minerals is that, by their very nature, they are not particularly well absorbed by the human body. This obstacle to absorption can be partially overcome by optimizing the form the mineral comes in. This is simple chemistry – certain forms of minerals are better absorbed than others. 

Thorne offers two forms of well-absorbed zinc – zinc picolinate and zinc bisglycinate – in many of their product formulas, as well as standalone products. Why choose one form over the other? That’s a good question, because both are excellent choices. Although zinc bisglycinate has data showing slightly better absorption compared to zinc picolinate, zinc picolinate has a longer history of use as a supplement and, as such, has been the subject of more clinical studies.

Absorption comparison studies

In one study, 12 healthy women were given single doses of zinc bisglycinate, zinc picolinate, zinc gluconate, or zinc oxide.4 With blood levels tested every hour for four hours, zinc bisglycinate resulted in the highest plasma zinc levels. In addition, zinc in red blood cells (RBC) was measured over the same 4-hour period. At the end of the study, RBC levels of zinc were in the following order from highest to lowest: zinc bisglycinate > zinc picolinate > zinc gluconate > zinc oxide.


Nevertheless, zinc picolinate is a well-absorbed form, too. When zinc bisglycinate is not being compared, one study found zinc picolinate exhibited superior absorption compared to zinc citrate and zinc gluconate, with significantly higher RBC, urine, and hair zinc after picolinate, compared to no increase in levels after citrate or gluconate.5

And better absorption means greater efficacy and tolerability.


  1. Jarosz M, Olber M, Wyszogrodzka G, et al. Antioxidant . . . effects of zinc. Zinc-dependent NF-κB signaling. Inflammopharmacology 2017;25(1):11-24.
  2. Haase H, Rink L. The immune system and the impact of zinc during aging. Immun Ageing 2009;6:9.
  3. DiSilvestro R, Swan M. Comparison of four commercially available zinc supplements for performance in a zinc tolerance test. FASEB J 2008;22:693.3
  4. Barrie S, Wright J, Pizzorno J, et al. Comparative absorption of zinc picolinate, zinc citrate and zinc gluconate in humans. Agents Actions 1987;21(1-2):223-228. 

An important note: No dietary supplement can diagnose, treat, cure or prevent any disease, including COVID-19. With the ongoing COVID-19 pandemic, it is especially important to understand that no dietary supplement, no diet, and no lifestyle modifications – other than the recommended social distancing and hygiene practices – can prevent you from being infected with the COVID-19 virus. No current research supports the use of any dietary supplement to protect you from being infected with the COVID-19 virus.