In 2014 they wrote: "Soylent is vegetarian but does contain fish oil. While no ingredients by nature contain gluten a preliminary test has shown gluten present at around the FDA limit of 20ppm, likely from the oats. We are working on sourcing certified GF oats but for now cannot claim to be fully GF."

So, they were GF by the US definition of gluten free, but not fully as in certified GF.