Will i lose muscle mass if i decrease the weight i lift and increase reps?

Will i lose muscle mass if i decrease the weight i lift and increase reps? I have built a, to be honest, amazing butt in the past 2 years in the gym. But recently i am only able to complete 6 reps on squats, deadlifts, etc, because the weight i lift is too heavy. I read an article and it said for...

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