Why Do Dermal Fillers Only Last Up to Two Weeks? (photo)

I use reputable clinics and Doctors so no issue with products. I've had Juvederm, Boletero & ZFill Repair to Nasolabial area and initial results are great. Is there a reason Fillers don't last in me, could it be my Metabolism? One Doctor told me I should have Sculptra, but at my regular clinic I was advised not to as they said my skin is still firm, line free and "collagen rich" at age 44 and Sculptra would cause over stimulation of collagen. Thank you