Estimates suggest that there are approximately 10 times more bacterial cells in and on the human body than there are human cells. The total number of bacterial cells is often cited to be around 30 to 40 trillion, whereas the number of human cells is estimated to be around 30 trillion as well. However, these numbers can vary based on individual factors, including body size, health, and diet.
It’s worth noting that the composition and number of bacteria can differ significantly between individuals and can fluctuate over time. The majority of these bacteria are found in the gut, but they also reside on the skin, in the mouth, and in other areas. While bacteria are often associated with disease, many bacteria are beneficial and play essential roles in digestion, immune function, and overall health.