Purpose: We examined the effects of collagen peptides (CP) supplementation on exercise induced-gastro-intestinal (GI) stress. Methods: In a randomized, crossover design, 20 volunteers (16 males: V ̇O2max, 53.4±5.9 ml·kg-1) completed 3 trials: a non-exercise rest trial, with no supplement (REST) and then an exercise trial with CP (10 g·day-1) or placebo control (CON) supplements, which were consumed for 7 days prior to, and 45 min before, a 70 min run at 70-90% of V ̇O2max. Outcome measures included urinary lactulose and rhamnose (L/R), intestinal fatty acid binding protein (I-FABP), lipopolysaccharide (LPS), anti-LPS antibody, monocyte chemoattractant protein-1 (MCP-1), interleukin (IL) 6 and 8, cortisol, alkaline phosphatase (ALP) (measured pre, 10 min post and 2 h post) and subjective GI symptoms. Results: There were no differences in heart rate, perceived exertion, thermal comfort, or core temperature during exercise in the CP and CON trials (all P>0.05). I-FABP was higher in CP (2538±1221pg/ml) and CON (2541±766pg/ml) vs. REST 2 h post (1893±1941pg/ml) (both P<0.05). LPS increased in CON vs. REST 2 h post (+71.8pg/ml; P < 0.05). Anti-LPS antibody decreased in CON and CP vs. REST at post (both P<0.05). There were no differences in MCP-1, IL-6, and IL-8 between the CP and CON trials (all P>0.05), and no differences in L/R or GI symptoms between CON and CP (all P>0.05). Conclusion: Collagen peptides did not modify exercise-induced changes in inflammation, GI integrity or subjective GI symptoms but LPS was higher in CON 2 h post-exercise and thus future studies may be warranted.