By expanding our understanding of this invisible microbial ecosystem, we better understand ourselves. In this episode, we learn more about how research is done, what the microbiome might look like, and ultimately what it means for humans today.

But as a quick overview, let’s talk about the interesting case of essential amino acids and essential fatty acids. “There are what we call essential amino acids and essential fatty acids. It means we need them, but we don’t produce them ourselves,” he tells me.

Essential fatty acids omega-6 and omega-31 vital for skin barrier function and overall health. Without them, we can experience inflammation, transepidermal water loss, and all the skin problems that come with it—sensitivity, fine lines, dullness, discoloration, and redness.

“And this has always been very mysterious to researchers: Like, if they’re so necessary, why don’t we make them?– he explains. – And the reason is that we never had to. We found ourselves in a world where microbes made them for us. So our bodies have never had these metabolic pathways.”

In fact, many of the nutrients we prioritize in our skin care are the same things our microbiome used to make for us. (We sometimes call these postbiotics, or the byproducts of living organisms on the skin.) We’re getting closer to understanding how best to care for this microbial world and rebuild what’s been lost, but we’re nowhere near done.

“This microbial world is the connective tissue for us biologically,” he says. “And we need to restore our relationship with him.”