GLP-1 Receptor Agonists: Weight Loss and Side Effects
GLP-1 medications are now at the center of many conversations. A friend is on treatment, a colleague has lost a significant amount of weight in just a few months… The transformations are fast, visible, sometimes striking—and they raise many questions.
Beyond the number on the scale, bodies are changing, faces are transforming, and new reflections emerge: Is it safe? Is this treatment right for me? And if the weight loss happens too quickly, will my skin keep up?
In this article, we offer a clear and nuanced perspective on this phenomenon: what happens in the body, the possible effects on appearance, and ways to approach these transformations with balance.
What are GLP-1 receptor agonists and how do they work?
GLP-1 (glucagon-like peptide-1) is a natural hormone released by the intestine after a meal. Its role? To send signals to the pancreas and the brain to help the body properly manage food intake.
This hormone acts on several levels:
- It stimulates the secretion of insulin, a hormone that allows glucose (sugar) to move from the bloodstream into the cells, where it is used as an energy source.
- It reduces the release of glucagon, a hormone that increases blood sugar levels.
- It slows gastric emptying, which delays digestion and prolongs the feeling of fullness.
- It acts on the brain to naturally reduce appetite.
Result: you eat less, blood sugar remains more stable, and the body uses energy more efficiently. This combination of effects has made GLP-1 a major target in medicine, both for diabetes and weight management.
Why are these medications prescribed?
For type 2 diabetes
GLP-1 receptor agonists were initially developed to help control blood sugar levels in people living with type 2 diabetes. They are often recommended when lifestyle changes (nutrition, physical activity) and first-line medical treatments (e.g., metformin) are no longer sufficient to maintain adequate glycemic control.
Some GLP-1 molecules also offer cardiovascular and renal protection. For individuals at risk, this can help reduce complications even when blood sugar is well managed.
For weight management
Over time, a significant effect on weight loss has also been observed. Some medications in this class are now approved in Canada to help adults with a BMI of 30 or higher.
They may also be considered for adults with a BMI of 27 or higher who have a weight-related condition, such as hypertension, sleep apnea, high cholesterol, or diabetes.
These medications are prescribed following a comprehensive medical evaluation and are part of a broader approach to weight management that includes nutrition, physical activity, and, when appropriate, psychological support.
These treatments are approved by Health Canada. However, when used for weight management, they are not covered by some public health insurance plans, such as RAMQ in Quebec. The cost of treatment may therefore be a barrier for some people.
Some GLP-1 medications approved by Health Canada in 2025
Several GLP-1 receptor agonists are approved by Health Canada. While they share a similar mechanism of action, they are not all indicated or equivalent for weight management. Treatment selection should always be made in collaboration with a physician, taking into account weight loss goals, overall health, budget, and insurance coverage.
Some treatments are approved for weight management (e.g., Wegovy, Zepbound, Saxenda, Rybelsus), while others are indicated for type 2 diabetes (e.g., Ozempic, Mounjaro, Victoza). Most of these medications are administered via subcutaneous injection, with frequency varying by product.
Who should not take GLP-1 medications?
These treatments are contraindicated in certain situations. They are generally not recommended if you have:
- a personal or family history of medullary thyroid cancer or multiple endocrine neoplasia type 2 (MEN2)
- current or past pancreatitis
- gastroparesis (delayed gastric emptying) or inflammatory bowel disease
- severe kidney disease (threshold varies depending on the molecule used)
- pregnancy or plans to become pregnant in the near future
- an allergy to these medications
- are breastfeeding
- diabetic retinopathy (for certain molecules)
A complete medical evaluation is essential before starting this type of treatment.
Possible side effects
The most common side effects are digestive, especially at the beginning of treatment:
- Nausea
- Loss of appetite
- Vomiting
- Constipation or diarrhea
These symptoms are often temporary and tend to subside over time.
Other possible effects include:
- Headaches
- Dizziness
- Injection site reactions
In rare cases, the following have been observed:
- Acute pancreatitis
- Acute kidney failure
- Severe allergic reactions
- Gallbladder issues
- Diabetic retinopathy
Regular medical follow-up is essential to ensure proper tolerance. Dosage is individualized for each patient.
Rapid weight loss: aesthetic effects not to overlook
The “Ozempic face”
When weight loss occurs rapidly, the face is often one of the first areas to reflect the changes. What is commonly referred to as “Ozempic face” can include hollow cheeks, volume loss in the temples, more pronounced under-eye hollows, skin laxity, and a duller complexion.
Facial features may appear more sunken, the skin less firm, and the overall face may look more tired or aged.
Different non-surgical treatments may be considered as part of a personalized treatment plan to address volume loss, skin laxity, and changes in skin quality. The approach depends on the changes observed, your skin, and your individual goals.
Perte de cheveux
Rapid weight loss can lead to decreased hair density. This phenomenon is often temporary and is linked to the changes the body is undergoing. Hair shedding may be diffuse. In some cases, androgenetic alopecia (male or female pattern hair loss) may be unmasked by this temporary shedding.
Depending on the cause and pattern of hair loss, different options may be considered as part of a personalized treatment plan. These can include prescription medications, either topical or oral, as well as PRP (platelet-rich plasma) injections to support hair regrowth and scalp health.
Skin Laxity & Muscle Tone
When the body changes quickly, it does not always adapt at the same pace. After significant weight loss, it is common to observe skin laxity, particularly in the face, abdomen, arms, or thighs. A reduction in muscle mass may also occur, affecting overall tone and body contour.
To achieve firmer skin and a more defined silhouette, non-invasive technologies can be integrated into your treatment plan. In some cases, when laxity is more severe, surgical options may provide more dramatic results.
Treatments That May Be Part of Your Plan
Rapid weight loss affects everyone differently. Depending on the changes you experience, a personalized treatment plan may help restore facial volume, improve skin quality, stimulate hair regrowth, or enhance skin firmness and muscle tone.
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Volume Restoration
Dermal fillers can help restore lost volume in areas such as the cheeks, temples, and under-eye hollows. Biostimulators like Radiesse and Sculptra may also be used to stimulate collagen production and gradually restore facial volume.
Skin Quality
Technologies such as Ultherapy, lasers, radiofrequency microneedling, and Sculptra can help improve skin firmness, tightening, and texture. Depending on your needs, these treatments may be combined with exosomes to support recovery.
Skin Radiance
Skinboosters, JetPeel, chemical peels, PRP, PRF, and skin resurfacing lasers can help improve skin hydration, texture, and overall skin quality.
Hair Loss
Several treatment options may help stimulate hair regrowth and revitalize the scalp, including topical or oral medications, PRP, PRF, exosomes, and microneedling. A consultation allows us to determine the cause of your hair loss and recommend the most appropriate treatment plan for your needs.
Skin Laxity & Muscle Tone
Technologies such as Thermage, radiofrequency microneedling, Emsculpt, and Electone can be incorporated into a personalized treatment plan. When skin laxity is more advanced, a consultation allows us to evaluate all available options and, if surgery is the most appropriate approach, refer you to the appropriate specialist or resources.
A Personalized Approach
Every weight loss journey is unique. That's why our specialists take the time to assess the changes you've experienced and develop a personalized treatment plan tailored to your goals and individual needs.
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