CLINICAL TRIAL - Mc Naughton, Bentley and Koeppel, 2006
In a placebo-controlled trial, the immune and stress responses were measured in exercise-trained adult males before and after endurance exercise, at baseline and after sixty days of Nucleotide supplementation.

Following exercise, cortisol was raised and salivary IgA levels were lower in all groups.
However, in the nucleotide group, cortisol and salivary IgA levels were significantly lower and higher in the nucleotide group, respectively, compared to the placebo group (Mc Naughton, Bentley and Koeppel, 2006).
Another placebo-controlled trial involving intense exercise showed similar findings with post-exercise cortisol response and IgA response being the lowest and highest, respectively, in the group taking nucleotides compared to the control and placebo groups (Mc Naughton, Bentley and Koeppel, 2007).