Weight-loss injections (GLP-1 drugs) beyond endocrinology

When exenatide first went on sale in 2005, or later, when liraglutide  was launched in 2010 as a diabetes medication and became popular as a way to lose weight, many saw how revolutionary it would be, but few could have predicted the craze that semaglutide (sold under the brand name Ozempic) and tirzepatide (sold as Mounjaro) would spark.

Today, both drugs are seen as a quick fix for long-coveted weight loss, not only helping people with diabetes and obesity (their on-label uses) but even serving as an option for those who “just want to lose three little kilos.” Little do they know that this is only a fraction of the health benefits these drugs can bring.

“The popular perception that GLP-1 receptor agonists are just ‘weight-loss drugs’ oversimplifies what these molecules actually do,” emphasizes endocrinologist Alessandra Rascovski, PhD, author of the book “Atmasoma – O equilíbrio entre a ciência e o prazer para viver mais e melhor.”

Endocrinologist Andressa Heimbecher, who holds a PhD in obesity from Universidade de São Paulo, points out that GLP-1 has been studied for some time, and it has long been known that it acts on many organs and systems in the body, such as fat cells, the pancreas, kidneys, heart, liver, musculoskeletal system, blood vessels and even in neuroprotection. “When drugs that are GLP-1 analogues were developed and we looked at the studies, we noticed, for example, a reduction in CRP. So we began to understand that the drug also had broader, more powerful actions,” the specialist explains.

What is GLP-1, and what are its analogues?

Before discussing the uses of GLP-1, it is important to explain what this hormone is and what it does in the body. It is an incretin, produced by the gut to help with communication between that organ and the brain, contributing to the perception of satiety. “More than 60% of the insulin released after a meal is due to the action of these substances,” Heimbecher explains.

Today, liraglutide and semaglutide are the substances drugmakers use to act like GLP-1 in the body; tirzepatide, meanwhile, also acts as an agonist of GIP, another important incretin in the body, with functions complementary to those of GLP-1.

But at the end of the day, the satiety and reduced appetite seen when taking GLP-1 analogues are only some of the ways this medication manifests in the body. “What we observe in practice is an overall improvement in the metabolic and inflammatory environment that accompanies conditions such as obesity, type 2 diabetes, metabolic dysfunction-associated steatotic liver disease (MASLD), cardiovascular disease and possibly some types of cancer,” Rascovski lists.

In which other specialties can GLP-1 analogues be used?

For Heimbecher, the watershed moment in this whole story was the SELECT trial, conducted with 17,604 patients (mean age 61.6 years and BMI 33.3 kg/m2) at high cardiovascular risk (secondary prevention – 95% with prior myocardial infarction and/or stroke). “The study showed that patients with overweight and obesity had a 20% reduction in cardiovascular events at the 2.4 mg dose,” the endocrinologist explains.

More recently, oncology has begun to observe a similar phenomenon. Studies presented at ASCO 2026 showed an association between the use of GLP-1 agonists and a lower incidence of several obesity-related cancers, as well as less metastatic progression in patients previously diagnosed with tumors such as breast, colorectal, lung and liver cancer. “It’s important to stress that these are association studies, meaning they do not prove that these molecules on their own are an ‘anticancer drug,’ Rascovski emphasizes.

Below, see how different specialties may find allies in GLP-1 analogues:

Hepatology: recent studies have shown a significant reduction in liver fat, improved inflammation and regression of advanced forms of MASLD/MASH, one of the fastest-growing chronic diseases in the world.

Cardiology: there is already robust evidence showing a reduction in major adverse cardiovascular events and heart failure, along with improvement in cardiometabolic risk factors.

Oncology: the data are still emerging, but observational studies point to a possible reduction in the incidence of some obesity-related cancers and less metastatic progression after diagnosis.

Rheumatology: reducing body weight lessens the load on the joints and improves osteoarthritis symptoms, especially in the knees. There are also studies indicating that patients with rheumatoid arthritis and obesity showed lower clinical disease activity, reduced pain and improved inflammatory biomarkers. As for psoriasis and psoriatic arthritis, in patients using tirzepatide in combination with biologics, rates of improvement in joint pain and control of skin lesions were considerably higher. This shows there is a likely direct immunomodulatory effect, with a reduction in inflammatory cytokines, and a beneficial effect on cartilage cells has even been postulated.

Dermatology: early studies also show GLP-1 analogues acting on atopic dermatitis in people with obesity. A systematic review published in the scientific journal Diseases in April 2025 showed that these drugs have a broad spectrum of dermatologic effects, ranging from immunomodulatory benefits to adverse skin reactions, and that their impact on inflammatory skin diseases suggests a new therapeutic pathway.

Neurology: there are ongoing studies evaluating possible benefits in neurodegenerative diseases such as Alzheimer’s and Parkinson’s, based on the anti-inflammatory, metabolic and neuroprotective effects of these molecules.

Gynecology and Reproductive Medicine: in women with obesity and polycystic ovary syndrome, GLP-1 agonists may help improve insulin resistance, body weight and metabolic parameters associated with reproductive function. They may also bring indirect benefits during the menopausal transition by meaningfully supporting control of weight and cardiometabolic risk.

Geriatrics and Longevity Medicine: by acting simultaneously on obesity, diabetes, inflammation, fatty liver, cardiovascular risk and sleep quality, these therapies affect multiple pillars related to healthy aging.

Treating obesity appears to be the key

In all the studies, patients with obesity and comorbidities achieved success in their treatment. “A large share of the patients followed by cardiologists, neurologists, oncologists, hepatologists, pulmonologists and geriatricians have some degree of obesity, insulin resistance, metabolic syndrome or adipose dysfunction,” notes Rascovski, who concludes: “These changes often represent a common denominator among different chronic diseases.”

But it is worth stressing that, as with everything in medicine, we cannot consider these medications a panacea. “These medications should not be seen as stand-alone solutions. The best results occur when they are part of a broader strategy that includes diet, physical activity, sleep, mental health and multidisciplinary care,” the endocrinologist says.

Either way, it is always worth staying up to date on this subject and asking: could my patients benefit from this type of treatment?