The problem is increasing longevity comes from a reduction of mTOR. Most muscle growth comes from an increase in mTOR(ie aminos,igf testosterone,calories,etc..) Increasing longevity typically involves reducing mTOR via autophagy, fasting, low protein, Metformin,etc.. not good if you’re trying to add muscle as that process mainly typically involves increasing mTOR. But then again increased IGF also increases longevity. So really it’s just a fine line and you can just play around with activation and deactivation methods for mTOR regarding your top priorities.