The "immunity supplement" category saw tremendous growth on Amazon over the last two years, posting an astonishing 165% growth rate from 2019 to 2020 to reach $623 million in 2020 revenue. This was in large part due to the pandemic.

Immune support supplements saw a very sharp increase during the initial months of the pandemic, followed by a sharp correction, and then leveling off in the summer months. This is in line with the usual performance of immune-related products—which are quite seasonal, declining in the summer months. However, since the correction, the category as a whole bounced back, and after a low point in August 2020, has seen month-over-month increases every month since. The category revenue for December 2020 was more than 2.5 times that of December 2019.

The supplement with the highest market share among immune health supplements was vitamin C, which saw 155% growth in the same period. Zinc, on the other hand, had the lowest market share at 11.5%, but this was more than double its market share in 2019, which was only 5.6%. This represents an incredible 442% growth year over year.

As the category with the most growth by far among immune-related supplements, zinc offered some interesting analytics.