Healthy weight or hidden risks? Why the evidence for GLP-1 treatments in older adults isn’t straightforward.
Glucagon-like peptide-1 (GLP-1) receptor agonists such as semaglutide (sold under the brand names Ozempic and Wegovy) and the dual GLP-1/GIP agonist tirzepatide (Mounjaro) have taken off in recent years. They are widely used to treat type 2 diabetes, but have also been shown to lead to substantial weight loss and improve cardiometabolic risk for those living with obesity. For many they are truly a miracle weight loss cure, but in adults over 60, the decision to use them is more complex than headlines suggest.
Medicine is always an exercise in weighing benefits against harms, and using GLP-1 drugs is no exception. Age changes how body weight interacts with muscle, bone and overall resilience, and in doing so can shift the balance of risk and benefits of using these medications when compared with younger people.
Although research shows there is very low uptake of these medications over the age of 60, there is no reason to believe that these drugs don’t work as well in older people, or have more side effects. Studies show good tolerance and effect in older cohorts. So the question as you get older isn’t “will I lose weight”; it’s “is weight loss the healthiest thing for me at this time”?
What is the “healthiest” BMI after 60?
In younger adults, there are clear health risks that begin to accumulate above a BMI of 25 kg/m². But once you get older, the risk of being overweight reduces compared with the risk of being a lower body weight. Large studies show the lowest mortality in people aged ≥65 lies in the BMI range 25–30 kg/m², not 18.5–24.9. Conversely, being underweight becomes a much greater risk as you age. At a BMI of below 22 in older adults, mortality risk increases, partly reflecting that at lower BMIs there is a higher rate of frailty and underlying illness.
This does not mean carrying excess weight is entirely risk-free. We know metabolic syndrome, which is strongly associated with carrying too much weight around your middle, is a major risk factor no matter your age. However, as you age, preserving muscle mass and preventing frailty becomes a more important predictor of outcomes.
Why metabolic syndrome still matters in older people
Metabolic syndrome (abdominal obesity, insulin resistance, hypertension and dyslipidaemia) is strongly associated with a range of poor health outcomes, including type 2 diabetes, cardiovascular disease and cognitive decline. Metabolic syndrome increases cardiovascular mortality risk by ~30–50%. We know as you get older, it is crucial to optimise your metabolic health to prevent diseases such as heart disease or dementia. But BMI is a poor indicator of metabolic syndrome when used in isolation. Factors such as waist circumference, triglycerides, HDL, blood pressure and HbA1c often predict risk better than BMI in older adults.
For older adults who are overweight and have metabolic syndrome, GLP-1 treatments can be a powerful risk modifier, as they have been shown to improve HbA1c, blood lipids and weight. Most importantly, they have been shown to directly reduce major cardiovascular events by 20% in overweight/obese adults with established heart or vascular disease. So understanding your individual metabolic risk is key when deciding whether to start these medications.
The critical issue: muscle and bone loss
Ageing is characterised by progressive loss of muscle mass and strength and this can strongly predict falls, disability, hospitalisation and mortality. Read more about muscle loss with age here.
For this reason, weight loss is not neutral as you age. Any kind of weight loss in older people is associated with loss of lean muscle mass, and aerobic exercise and strength training often only attenuates rather than prevents this. So as you get older, the benefits of losing weight, through GLP-1 treatments or otherwise, do have to be balanced with the risks.
GLP-1 treatment-driven weight loss has been shown to unavoidably include loss of lean mass. Body composition analyses from the SURMOUNT trial showed that approximately 25% of total weight loss is lean mass. In younger adults this may be manageable but in older adults who are already fighting age-related muscle loss, this might accelerate frailty.
It's not just muscles that may be at risk. Intentional weight loss (without using GLP-1 medication) in older men has been associated with reduced bone density and increased fracture risk. Preliminary research suggests the risk of osteoporosis is around 30% higher in those who use GLP-1 medications compared with those who don’t- although this may be higher in older adults.
GLP-1 drug trials have not yet produced robust fracture data for older adults, and older or frail people are under-represented in the main GLP-1 drug trials. However paired with what we know about loss of muscle mass with these medications there is inherent risk here: reduced strength could increase falls, and lower bone density could increase fracture risk. This is leaving aside the theoretical risk that the common GLP-1 medication side effects of nausea, diarrhoea and vomiting could have more profound impacts for older people, who are already at greater risk of the effects of dehydration or malnutrition.
For those with obesity and high cardiovascular risk, metabolic benefits may outweigh these concerns but in individuals who are already at risk of weak muscles, bones or frailty, further muscle and bone loss may shift the balance toward harm. The only way to get a better understanding of how much the relative risks are is to wait for better clinical trial data on outcomes specifically for older people.
So should people over 60 take GLP-1s?
The answer is highly individual, and shouldn’t be solely guided by the number on a weighing scale. Those for whom metabolic syndrome is a problem and who have a very high cardiovascular risk may benefit, particularly if they are able to perform the focused resistance training necessary to mitigate muscle loss.
Conversely, for those who have higher risk of sarcopenia or osteoporosis, or a lower risk of cardiovascular disease, the balance may lie in favour of carrying a bit of extra weight. Metabolic health can be optimised through other means and these medications are far from the only avenue. Gradual weight loss through diet and exercise might be preferable and more muscle-sparing than the rapid weight loss experienced on GLP-1 treatments.
Practical safeguards for older adults who choose GLP-1 therapy
For those who are taking GLP-1 treatments in older age, there are a few principles that can help optimise safety.
- Do not aim for rapid weight loss
- Progressive resistance training at least 2–3 times per week to preserve muscle mass
- At least 150 minutes of moderate intensity aerobic exercise to maintain functional status
- Even if portion sizes decrease, ensure a healthy, nutrient and fibre rich diet to optimise health
- Aim for protein intake ≥1.0–1.2 g/kg/day
- Ensure adequate hydration
- Optimise vitamin D, calcium and monitor bone density
- Monitor functional strength (grip, chair rise, gait speed) and not just weight
Conclusion
The healthiest BMI for many people over 60 may lie in the 25–30 range and being slightly overweight is not automatically harmful, particularly for older people. A reduction in weight might not lead to net benefit if it costs strength, balance and independence.
Metabolic syndrome remains dangerous at any age however, rather than focusing on weight alone, a holistic approach to measuring and improving metabolic health becomes increasingly important as you age. GLP-1 medications are a powerful way to tackle cardiovascular risk in older people, but they are not the only way.
GLP-1 medications can meaningfully reduce cardiometabolic risk but they also induce lean mass loss, and muscle strength is a critical determinant independence and survival in later life. The physiology of older adults is complex and as we get more data on the risks and benefits in this age group, we may be able to comment more conclusively on their appropriateness for these cohorts.
For now, however, they should be approached conservatively in older adults. Used selectively, particularly in those with obesity and cardiovascular disease or diabetes, and combined with structured resistance training and adequate protein intake, they may be a good option for improving long-term health. Used indiscriminately they risk accelerating the very decline that we are looking to prevent. As you get older, good functional status and quality of life is the correct goal to pursue, rather than chasing a ‘normal’ BMI at any cost.
