What is the best way to build lean muscle after the age of 35, as a man?

Build lean muscle after 35 with regular resistance training, progressive effort, and enough recovery; age alone is not a reason you can’t gain muscle. A practical starting point is three or four short sessions weekly, increasing challenge over time. 1 2

• 5–15 sets per muscle each week: Use this as a general range, adjusting for how hard you train and how readily you can recruit the muscle. Most sets need not be taken to failure; distribute sets across sessions if that helps you recover. 3 4
• Include strength training: Resistance training can increase muscle and strength with age, rather than relying on endurance exercise alone. 5 6
• Use recovery work: Leave time for recovery between sessions; stretching or other recovery practices specifically for flexibility and range of motion aren’t addressed in the available evidence here. 7
• Growth hormone: Exercise, sleep, and nutrition as ways to support growth hormone levels are not covered in the evidence available here.
• Track body composition: A DEXA scan is one option for assessing body composition and muscle-related measures. 8