Comment by ac29

> Whether or not the effect in the paper turns out to be true and reproducible, the supplements you've seen almost certainly don't do anything unless you're wiping out your established gut microbiota with antibiotics first. Your existing microbiota are entrenched and in a very good position to defend themselves from any weakened intruders you might intentionally introduce.

There is an ton of probiotic research that shows probiotics can survive transit to the gut and reproduce there.

Even without probiotic supplmentaion, you microbiome absolutely can and will change over time.