The first human digestion clinical trial testing the A1 and A2 milk proteins took place at Curtin University in 2014 and was published in the prestigious European Journal of Clinical Nutrition (EJCN).

The results of the double blind, randomised digestion study supports findings of previous animal studies that there are differences in gastrointestinal effects between milk containing A1 versus A2 beta-casein protein (A1 and A2 protein).
Associate Professor Sebely Pal of Curtin University, who led the research, said: 「This pilot study shows that A2 Milk, because it doesn’t have any A1 beta-casein, has different gastrointestinal effects. The milk that contained A1 beta-casein led to statistically significant differences in stool consistency, with the A1 being looser. This effect was particularly strong for women.」