Introduction: Physical exercise can increase metabolism in the liver due to the presence of alkaline phosphatase (ALP), which subsequently causes the oxidative stress. In order to reduce this effect, the consumption of natural antioxidant is commonly performed, and one of these antioxidants could be found in mangosteen peel that contains high content of Xanthone and Procyanidin. This study aims to understand the effect of mangosteen peels to alkaline phosphatase serum in male student group who have performed heavy exercises. Methods: A true experimental study was carried out with pre- and post-test, and 21 male students were recruited which were divided into two groups. To understand the effect, a control group which was instructed to prescribe placebo was involved, whereas the other group was invited to consume mangosteen peels with dosage of 550 mg as their supplements. Both of the groups were prescribed for two weeks before performing the exercise, in which they were invited to perform treadmill exercise which had 75%-85 of intensity for three times a week. The ALP levels were measured on the final day of treatments after performing the heavy exercise. Results: A significant rise of ALP levels were demonstrated by the control group with p value <0.05, in contrast the group who has consumed the mangosteen peel as their supplements had significantly lower ALP levels compared to the placebo group. Conclusion: It is concluded that mangosteel peels had the ability in lowering the ALP serum levels in male students who have performed heavy exercise.