GLP‑1s, from a doctor’s lens: what they do, who should consider them, and what’s next
Ozempic, Wegovy, Mounjaro, Zepbound. You’ve likely heard these drug names, even if you’ve never taken them. For many, they symbolize a new era in weight‑loss science and one of the most talked‑about developments in modern healthcare.
But behind the buzz, you may be surprised to know that GLP‑1 receptor agonist medications have been used clinically since 2005, when they were introduced to help manage diabetes. The recent surge happened when Wegovy became the first GLP‑1 approved in 2021 for chronic weight management. One year later, trial results with semaglutide – the medication’s clinical name – showed a ~15.8% average body‑weight loss and drew widespread public attention.
As awareness grew, prescriptions also climbed. GLP‑1 use for weight loss and obesity rose 587% from 2019 to 2024, and prescribing for people without diabetes increased 1,961% over the same period. The rise also coincided with broader recognition of obesity as a chronic, treatable disease, not a personal failing, further normalizing GLP‑1s as evidence‑based tools in clinical care.
Today, GLP‑1 drugs are part of everyday conversations. You’re likely to know someone who takes one – or you may be wondering whether you should. At Medcan, we are regularly asked questions like: What do these medications do? When are they appropriate? And what should you expect?
In this article, our Medcan physicians address common questions, share how we approach GLP‑1s, and offer clinical insight into this revolutionary medication.
Who might benefit from a GLP-1?
Given GLP-1 medications are widely used for weight loss, a responsible conversation about them starts with education on the root causes of obesity and weight gain.
Dr. David Macklin, Clinical Director of Medcan’s Weight Management program, co-authored the Canadian obesity guidelines and is a world-renowned expert on the topic. He emphasizes that obesity should not be stigmatized; it’s a chronic disease with strong genetic and environmental drivers. Hence, even the terms ‘obesity’ and ‘overweight’ should be used deliberately as names of conditions, not identity markers caused by a person’s behaviour.
According to Dr. Macklin, most people don't understand that the risk of living with overweight and obesity is primarily inherited. Approximately seventy percent of the variability of size in all humans is heritable. There may be as many as 1500 individual variants of genes that determine your risk of struggling with weight in your lifetime.
In addition, the majority of genes that influence weight are expressed in the brain. Most of the differences in risk are based on differences in three areas that regulate metabolism, appetite and weight.
Dr. Macklin explains that the human brain was also built for a time when calories took work to acquire. “Now we’re living with our modern food environment, and those who are genetically vulnerable will experience appetite dysregulation – meaning they will take in more calories than they need and store more fat than is healthy – because of genetic adaptations.”
When you combine genetic predisposition with today’s highly processed, sugar-laden, hyper‑palatable food economy, it creates a perfect storm for the obesity epidemic. The real concern when it comes to health is that obesity is a risk factor for many conditions, including metabolic and cardiovascular diseases, which can seriously impact lifespan and quality of life.
But this is where GLP-1 medications come in, and why their advent is revolutionary.
"In our modern food environment, those who are genetically vulnerable will experience appetite dysregulation because of genetic adaptations."- Dr. David Macklin, Clinical Director of Medcan's Weight Management Program
How do GLP-1 medications work?
A GLP‑1 medication copies a natural hormone in your body called Glucagon-like peptide 1, or GLP-1 for short. The hormone is normally released after you eat to help control blood sugar and appetite. It helps your body balance energy intake and expenditure and influences how hungry or full you feel.
Therefore, a GLP‑1 receptor agonist medication mimics the natural GLP‑1 hormone your body makes. These medicines attach to GLP‑1 receptors, which are proteins found on cells in your body (mostly in the pancreas, stomach and brain) and activate them, just like real GLP‑1 would.
GLP-1 medications help your body in four ways, to:
- Handle sugar more effectively
- Feel full sooner
- Eat less
- Maintain steady energy
All GLP‑1–only receptor agonists share appetite dysregulation and normalization effects because they act on the same GLP‑1 pathways in the brain and gut. However, the strength of appetite suppression differs between drugs.
Taking a GLP‑1 medication doesn’t mean your body’s GLP‑1 hormone is “broken”. However, it’s likely your body isn’t responding to food, insulin, and appetite signals as well as it should. GLP-1 medications help boost natural GLP-1 signals.
For example, in people with type 2 diabetes, the body has problems with insulin and blood sugar control. GLP‑1 medications help enhance insulin release, reduce glucagon (a hormone your body makes to raise your blood sugar when it gets too low), slows digestion, and reduces appetite. These are all ways the natural hormones work, just not strongly enough in some people.
For those with obesity, GLP-1 medications can help manage appetite dysregulation. Appetite dysregulation happens when the body’s normal system for controlling hunger and fullness is disrupted. Normally, appetite is regulated by a coordinated network involving the brain, hormones, digestive system and environmental cues. When this system becomes imbalanced, a person may feel hungry when the body doesn’t need energy or they may not feel hungry even when energy is required.
The body’s natural GLP‑1 typically also breaks down within minutes; only about 10–15% survives long enough to work. Since it disappears so fast, it's helpful effects don’t last. GLP‑1 medications are designed to stick around much longer, giving the body a stronger, steadier version of the hormone’s normal actions.
Are GLP-1s for everyone?
When it comes to GLP-1 medications, there is no one‑size‑fits‑all directive. It must be a personal choice in collaboration with a physician, and based on individual needs, lifestyle, and medical history. It should also be considered as part of an integrated approach to weight management that does not rely on medication alone. It should include proven strategies such as cognitive behavioural therapy and nutrition coaching.
A GLP-1 may be suggested for anyone that falls in these categories:
- Adults with type 2 diabetes
- Adults with obesity (BMI ≥ 30)
- Adults with BMI ≥ 27 + a weight‑related condition (such as high blood pressure, sleep apnea, or heart disease)
- Adults who need help managing conditions like heart disease risk or MASH, a serious liver disease
There are also some contraindications, such as pregnancy, those with a family history of medullary thyroid cancer, pancreatitis, and other conditions. It is imperative that a decision to take these medications is thoroughly discussed with your physician.
Medcan Vice President of Medical Affairs and Medcan Dedicated Care physician, Dr. Jason Abrams, frequently discusses GLP-1 medications with his patients. He approaches these conversations through education, explaining the potential benefits and drawbacks of the medication in the context of the client’s personal health history and goals. “Ultimately, it should be a patient-led decision,” he emphasizes.
Before you and your doctor decide that a GLP-1 is right for you, you’ll want to consider what you have already tried to manage weight-related conditions and related health concerns. GLP-1s are meant to work with lifestyle changes, not replace them. Dr. Abrams cautions against thinking medication replaces lifestyle choices. “Like with many other medical treatments, GLP-1s are intended to work in concert with - not replace - lifestyle management,” he explains.
If you would like to have a conversation on GLP-1s with your doctor, be prepared to discuss your journey so far: what have you tried? Where have you been successful? Where are you still struggling?
You and your physician can then review the pros and cons and determine the best course of action for your health and wellbeing.
“Like with many other medical treatments, GLP-1s are intended to work in concert with - not replace - lifestyle management."- Dr. Jason Abrams, Medcan's Vice President of Medical Affairs
Benefits of GLP-1s – weight loss and beyond
GLP‑1 medications can support meaningful weight loss and continue to reshape treatment of metabolic issues like obesity and diabetes.
For those with elevated blood pressure, cholesterol, or elevated hbA1c levels (a metric of prediabetes or diabetes), they may improve these markers and reduce the need for other medications. When it comes to type 2 diabetes in particular, Medcan Endocrinologist, Dr. Amish Parikh, says, “Clinically, we’re seeing HbA1c reductions, weight loss and cardiovascular benefit.”
He notes that many patients on GLP-1 medications need less insulin than before, or they can wait longer before starting it. And if they do need insulin, using it together with a GLP‑1 medication helps prevent the weight gain that usually comes with insulin. This is a big improvement compared to how obesity and diabetes were treated 20 years ago.
A promising future
Beyond weight and metabolic impacts, GLP‑1s have demonstrated cardiovascular benefits in randomized trials which have also shown that they may reduce major adverse cardiovascular events (MACE).
Evidence is also emerging for kidney protection and improvements in fatty liver disease, which is a breakthrough. According to Dr. Abrams, “for years, we had no pharmacologic option for fatty liver, but now, a GLP‑1 may help modify its course in some patients.”
Furthermore, Dr. Macklin points out encouraging insights that link GLP-1s to alcohol and shopping addiction, which are activated by similar pathways in the brain as overeating.
As research continues, many experts anticipate broader roles for GLP‑1–based therapy. Soon we may see it used not just in diabetes and obesity, but across related conditions such as heart failure, chronic kidney disease, autoimmune diseases, sleep apnea, addictions like alcoholism, and even neurodegenerative disorders (although recent trials for Alzheimer’s have failed).
Many experts, in and outside of Medcan, also view GLP‑1s as part of a broader shift from treating single biomarkers to targeting whole‑body metabolic pathways. Since these drugs influence the cardio‑kidney‑metabolic axis, they may help address multiple chronic conditions at once rather than in silos.
A wave of next‑generation GLP‑1–based medicines are currently under development. These drugs will be designed not only to mimic natural GLP‑1, but to work on multiple metabolic pathways at once for greater weight‑management effectiveness, better long‑term durability, and easier dosing. Additionally, oral versions (versus injections) continue to be a focus for improved convenience.
Ongoing research is focused on understanding who responds well, who doesn’t, and which biological markers - like genetics, hormone profiles, or body‑fat patterns - can predict success or side effects, so treatment can become more personalized over time.
Side effects and important considerations
Like other medications, those taking GLP-1s may experience side effects. Short‑term gastrointestinal symptoms such as abdominal pain, diarrhea, and nausea are the most common, but there can be other effects depending on the individual. Your doctor should discuss the potential risks and side effects you should be aware of when making the decision to take GLP-1 medications.
Digestive side effects can usually be mitigated through adjustments in dietary consumption. Dr. Parikh gives practical tips to manage tolerability. “GLP‑1s slow gastric emptying, so eat slowly and have smaller meals.” He also suggests that some people use an over‑the‑counter anti‑nauseant short‑term, if needed, and in consultation with their clinician.
Long‑term considerations include gallstones or gallbladder disease, and there is some evidence suggesting pancreatitis risk. GLP‑1 labels also carry a boxed warning about certain thyroid cancers based primarily on rodent data. People with personal or family history of MTC or MEN2 should not use these drugs. Other thyroid cancer types do not automatically preclude use, though some patients may choose to avoid them.
For those who are concerned that taking a GLP-1 medication can lead to muscle loss, Dr. Macklin provides some myth-busting. He says that muscle loss is a consequence of weight loss, not GLP-1s. (We provide a deeper dive on this topic along with tips for maintaining muscle during weight loss here).
Is a GLP-1 a short- or long-term medication?
Many patients wonder, Can I take a GLP‑1 for three to six months, jump‑start weight loss, then stop?
For GLP-1s there is no lasting “legacy effect.” When the drug is stopped, weight regain is common because appetite and cravings return; what felt like a permanent behavioural shift was, in many cases, pharmacologic appetite suppression. In other words, it was caused to be a GLP-1 medication that the body needed for support.
Again, Dr. Macklin emphasizes that taking a needed medication should not be stigmatized. “If you have hereditary high LDL cholesterol, you’ll likely require a statin for the rest of your life. GLP-1 medications to manage hereditary appetite dysregulation should not be viewed any differently. When you stop taking the medication, the medication stops working.”
Many clinicians will explain to patients that GLP‑1 medications are intended for long‑term use. Currently, there is ample research that shows that when these drugs are discontinued much of the weight loss and metabolic improvements are typically regained.
The takeaway
While GLP-1 medications are revolutionary in this time of the obesity epidemic and alarming rates of type 2 diabetes and heart disease, it is important to remember that GLP‑1s are powerful tools to complement an integrated health strategy. Your physician should partner with you to take an educated, comprehensive approach that is rooted in best practices to manage obesity, overweight, or diabetes.
If you’re considering a GLP‑1, talk with your healthcare provider. Working with a trained physician, together, you can map a plan that’s safe, realistic, and aligned with helping you live a long, healthy life full of energy and vitality.
Take Action
Led by renowned Canadian obesity expert Dr. David Macklin, Medcan’s Weight Management Program is a one-year program that offers one-on-one guidance from our interdisciplinary team of expert physicians and dietitians.
The program includes cognitive behavioural therapy treatment, science-based nutrition education, fitness coaching, body composition analysis, GLP-1 guidance, and personalized care throughout. Learn more here.
For those looking for a highly personalized primary care experience, Medcan’s Dedicated Care program offers members appointments, care plans, referrals, all coordinated by a centralized clinical team with a personal physician at the centre. Additional features including an in-depth health and wellness package and preferred rate on the Annual Health Assessment. Explore Dedicated Care.
This article was written by Medcan’s editorial team with review and contribution from Dr. David Macklin, Clinical Director of Medcan’s Weight Management Program; Dr. Jason Abrams, Medcan’s Vice President of Medical Affairs, and; Dr. Amish Parikh, Medcan Endocrinologist.
In addition to his role at Medcan, Dr. Macklin helped write the Canadian guidelines for obesity. He also receives consulting fees, honoraria, and licensing fees from Novo Nordisk, the manufacturer of semaglutide under the trade name Ozempic, as well as Eli Lilly, the manufacturer of Mounjaro and Zepbound.
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This content is for informational purposes only and should not be taken as medical advice. Please consult a Medcan clinician or your healthcare provider for guidance tailored to your health needs.
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Medcan’s Weight Management & Nutrition Programs offer comprehensive non-judgmental support from a multidisciplinary team. Our year-long Weight Management Program is led by Dr. David Macklin, a renowned obesity specialist and a co-author of Canada’s obesity guidelines in adults. Medcan's Nutrition Programs are led by one of Canada’s renowned dietitians, Leslie Beck, RD, and tailored to your individual health goals.