Aims: This study investigated the effects of creatine and L-carnitine supplementation on anaerobic

performance and body weight changes in athletes. Methods: In this single-blind randomized clinical trial, 45

athletes were selected and randomly divided into four groups supplemented with: a) Creatine, b) L-carnitine,

c) Creatine- L- carnitine and D) placebo. The supplementation period was 28 days. Wingate anaerobic test

was done for assessing athletes' anaerobic performance and their weights were measured before and after

the supplementation period. To compare the variables before and after each test, paired t-test and anova

are used compare within and between variables respecdivey. Results: The anaerobic performance indices

in the groups receiving creatine and creatine- L-carnitine were significantly increased after intervention. Body

weights were also significantly increased in the supplemented groups. Conclusions: Based on the dosage

and duration of supplementation in this study, concurrent creatine and L-carnitine supplementation has

positive effects on anaerobic performance. Despite L-carnitine is a weight loss agent, the findings of this

study showed weight gain in the supplemented groups.