“You can't build meaningful muscle after a certain age.”
Strong confidence. Trials and meta-analyses show that adults in their late 70s, 80s and beyond can improve muscle strength and often muscle size with progressive resistance training. Age can reduce or slow the response, but it does not create a fixed cutoff.
There is no age at which meaningful muscle or strength gain becomes impossible for everyone. Older adults, including very old and frail participants, have improved with appropriately scaled resistance training.
Training response varies with health, protein and energy intake, medications, sleep and program design. Strength and function may improve even when visible muscle-size change is modest.
Safety note: Older adults should scale exercise to current function, balance and medical status. Supervision or stable machines may be useful when fall risk or frailty is present.
Talk to a healthcare professional if: Get individualized clearance or rehabilitation guidance after a recent fracture, surgery or major cardiac event, or with unstable disease, unexplained exertional symptoms or substantial fall risk.
Starting later can still be worthwhile. The program may need more gradual progression and recovery, but age alone is not a reason to avoid strength work.
Begin with stable exercises at a manageable effort two or more days per week and progress resistance or repetitions gradually. Qualified coaching can help with technique and adaptation.
Similar claims on Exercise and aging (sarcopenia, falls)
It is never too late to get stronger - training in later life is one of the highest-impact things for staying independent and fall-free. Muscle is health insurance for aging.