does anyone knows if it makes me lose muscles or dificults bodybuilding?

Pesta et al. found that although there was no significant decrease in things like grip strength, overall physical work capacity during bodybuilding decreased by 25% in those who used. This may be accounted for by what Renaud and Cormier found, which is that tested subjects who smoked marijuana 10 min before noted a slight but significant decrease in time to exhaustion. Steadward and Singh demonstrated that marijuana did not affect blood pressure, ventilation or oxygen uptake during submaximal exercises such as bodybuilding, however it did increase heart rate both during and after lifting.