A 2016 study published in PLOS Biology found that the average human plays host to trillions and trillions of microbial cells (read: bacteria, yeast and parasites), many of which form a barrier on top of the skin that is often referred to as the “skin microbiome.” The skin microbiome plays an important role in protective bodily functions, and the ecosystem of bacteria found here is more diverse than that found in both our guts and mouths.

But how exactly should natural products consumers go about keeping their skin and mouth microbiomes healthy and happy? For starters, “feeding” the good bacteria with specially formulated prebiotic-based products can help lessen irritation while keeping mold and harmful live bacteria strains at bay.

Prebiotic-containing personal care products are especially helpful for consumers with sensitive skin and gums—and the former is reportedly on the rise according to survey results from Frontiers in Medicine that were published earlier this year. Whether it’s from pollution, plain old winter dryness, over-exfoliation or excess sun exposure, prebiotics can indirectly help repair the skin mantle while stimulating the growth of good bacteria.

So, give your shoppers the ability to care for their precious and easily affected skin and mouth flora by enhancing your personal care aisle with these four impressive prebiotic-rich products.