Your gut bacteria turn the hyaluronic acid you swallow into tiny pieces that your body can absorb; if you don’t have those bacteria, your body can’t absorb anything from it.

Bacteria in the gut break down a substance called hyaluronan into tiny pieces, and some of those tiny pieces get absorbed through the gut wall in mice.

In mice, certain good bacteria in the gut called Bacteroides are needed to turn a substance from the mouth called hyaluronan into tiny pieces that the body can absorb.

When your body doesn’t absorb certain pieces of hyaluronan (a substance found in joints and skin), your gut bacteria break them down into tiny fatty acids—and in mice, these fatty acids are the only things your body gets from those bacteria.

When mice eat certain types of hyaluronan, their bodies break down the parts they can’t absorb directly into tiny fatty acids, and those fatty acids are the only things their bodies can actually use from this substance.