June 9th, 2026
Fecal microbiota transplantation from young donor to old recipient can reset the composition of the aged gut microbiome to produce benefits to health. Animal studies are very positive. Unfortunately fecal microbiota transplantation doesn't mix all that well with the present approach to regulation of medicine in the US and EU. One product, meaning one approach to donor screening and some attempt at standardization, has been approved by the FDA for use in the treatment of C. difficile infection. Following that the FDA has made it hard for other donor screening and connection services such as Human Microbes to operate at all for any purpose in the US, so for most people the situation is now worse than it was.
Regulators want standardization, which is always going to be challenging and expensive to achieve for donor material given the high human to human variability in gut microbiome composition. So the incentive exists to develop the means to create artificial gut microbiomes with a standarized composition. Unfortunately the state of probiotic manufacture is a long way removed from being able to assemble hundreds or thousands of species in defined proportions in a cost-effective manner. Still, inroads are being made; if researchers can produce a 15 species mix today, then working with defined mixes of hundreds and then thousands of species will become viable in time.
