There is a version of this conversation that ends with “not at your age”, and it is usually wrong. The cardiovascular outcome trials enrolled plenty of people in their sixties and seventies, and the benefit did not evaporate.
There is another version that treats a seventy-two-year-old exactly like a forty-two-year-old, and that is wrong too. What changes is not whether the drug works. It is what the collateral costs mean in a body with less reserve.
Sarcopenia, which is the central issue
Muscle mass declines with age at roughly three to eight percent per decade after thirty, accelerating after seventy. Superimpose a drug that takes a quarter to a third of lost weight from lean tissue, and the arithmetic gets serious quickly.
The distinction that matters is between weight and function. A seventy-year-old who loses thirty pounds and can no longer rise from a chair unaided has had a bad outcome, regardless of what the scale or their blood pressure says. Sarcopenic obesity — low muscle with high fat — is a worse functional state than obesity alone, and it is possible to move someone toward it by treating their weight carelessly.
This is not an argument against treatment. It is an argument that in this age group the resistance training and protein components stop being advisable and become part of the prescription. The Villareal trial found precisely this in older dieting adults: weight loss plus exercise preserved function in a way weight loss alone did not.
Practical targets: protein at the upper end of the range, around 1.2 to 1.6 g per kilogram, and resistance work two to three times weekly. The broader argument is in the muscle question, and the practicalities of training on a small appetite are in exercising on a GLP-1.
3–8%
Muscle mass lost per decade after thirty, accelerating after seventy
Chair rise
A better functional measure in this group than any number on a scale
Grip strength
The other simple bedside measure worth tracking through weight loss
EWGSOP2 criteria
Bone and falls
Weight loss reduces bone mineral density at any age — mechanical loading falls as body weight falls. In someone already osteopenic, and already at risk of falling, that combines badly with muscle loss.
Reasonable measures: ensure calcium and vitamin D adequacy, include weight-bearing and resistance exercise, and consider a baseline DEXA scan, which measures body composition as well as bone. A fracture risk assessment is worth having before rather than after.
The related picture in women through the menopausal transition is in GLP-1s through menopause, and the supplement approaches people commonly take are compared in supplements over 50.
Dehydration, which is the acute danger
This is the one most likely to produce a hospital admission.
Older adults have a blunted thirst response before any drug is involved, reduced renal reserve, and are far more likely to be taking diuretics, ACE inhibitors, ARBs or SGLT2 inhibitors. Add a medication that suppresses appetite and thirst together, then add a week of vomiting, and acute kidney injury follows readily.
Polypharmacy, in both directions
Weight loss changes what other medications should be doing.
Blood pressure medication frequently becomes too strong. Dizziness on standing at month four in a seventy-year-old is often over-treated hypertension rather than dehydration — and it can be either, which is why it needs measuring rather than guessing.
Insulin and sulfonylureas need reducing, usually substantially, and again at each dose step. Hypoglycaemia in an older adult is a falls risk as much as a metabolic event, and it presents atypically — confusion rather than sweating.
Levothyroxine, warfarin and other narrow-window drugs may need monitoring around starting, per drug interactions.
Deprescribing as weight falls is one of the genuine wins here and it does not happen automatically. Somebody has to be looking.
What the goal should be
Frequently not maximal weight loss.
In an older adult the aims are usually better glycaemic control, reduced cardiovascular risk, improved mobility, less joint loading, and better sleep apnoea. All of those are largely achieved in the first five to ten percent.
Which argues for stopping at an effective dose rather than climbing to the ceiling — a legitimate endpoint that the dose charts make clear is built into the licensing, particularly for tirzepatide with its three maintenance doses. Slower escalation also reduces the gastrointestinal effects that are less well tolerated in this group; the expected timeline is in how long side effects last.
There is also a coverage dimension that hits this group hardest. Medicare Part D cannot cover drugs for weight loss, which is why the cardiovascular and sleep apnoea indications matter so much here — see the Medicare fight, the pricing deal and the SELECT label change.
The question at seventy is not how much weight came off. It is whether they can still get out of a chair, and whether anybody checked.
The summary
Treat, but treat differently. Slower titration, a lower target dose, protein and resistance training treated as part of the prescription rather than as advice, a written sick-day plan, and a scheduled review of every other medication as the weight comes down.
Done that way this is a good drug in older adults. Done as it is done in a forty-year-old, it can leave someone metabolically improved and functionally worse — which is not a trade anybody agreed to.