How do GLP-1 agonists help with weight loss?

All of these drugs are GLP-1 agonists. They were originally developed for type 2 diabetes but have turned out to be highly effective for weight loss. Without getting into the mechanism, they mimic a hormone that makes you feel full, slows stomach emptying, and helps control blood sugar. You feel fuller for longer, eat less, and crave fewer sugary foods, which leads to weight loss.

Key Differences

When comparing these medications, we’ll focus on their effectiveness for weight loss and method & frequency of administration.

Effectiveness for Weight Loss

Ozempic (Semaglutide): While primarily for type 2 diabetes, it has demonstrated substantial weight loss benefits, though typically less than Wegovy due to its lower dosing for diabetes management.

Wegovy (Semaglutide): Shown to be highly effective for weight loss in clinical trials, with participants losing up to 10-15% of their body weight on average.

Mounjaro (tirzepatide): Offers strong weight-loss results in tirzepatide trials because it acts on both GLP-1 and GIP receptors. In Canada, Mounjaro is primarily a type 2 diabetes product, while Zepbound is the tirzepatide product marketed for weight management.

Zepbound (tirzepatide): A weekly tirzepatide injection for weight management. It has similar expected weight-loss effects to tirzepatide, but pricing, packaging, and insurance rules differ from Mounjaro.

Saxenda (Liraglutide): Effective for weight loss, with average losses of around 5-10% of body weight, though generally less effective than higher-dose semaglutide (Wegovy) or tirzepatide (Mounjaro).

Rybelsus (Semaglutide): The oral form of semaglutide shows effectiveness similar to Ozempic, but potentially less convenient and slightly less effective for weight loss due to the nature of oral absorption.

Administration & Frequency

Ozempic: Given as a weekly subcutaneous injection. Designed for diabetes treatment but used off-label for weight loss at doses lower than Wegovy.

Wegovy: Administered via subcutaneous injection once a week. Its high dose of semaglutide specifically targets weight loss.

Mounjaro: Also a weekly subcutaneous injection. Its unique action on both GLP-1 and GIP receptors makes it useful for diabetes management and weight loss in appropriate patients.

Zepbound: A weekly tirzepatide injection used for weight management.

Saxenda: Requires a daily subcutaneous injection. While effective, the daily administration may be less convenient for some people compared to weekly options.

Rybelsus: The only one in pill form, taken orally once daily. While convenient, the effectiveness for weight loss might be slightly reduced compared to injectable forms.

How much weight can I expect to lose in a month?

The amount of weight one can expect to lose in a month can vary significantly depending on several factors including starting weight, diet, exercise habits, overall lifestyle, and whether any weight loss medications are used.

As a baseline, with diet and exercise alone, a common guideline for safe and sustainable weight loss is 1-2 pounds per week. This translates to about 4-8 pounds in a month. Achieving this typically involves creating a calorie deficit of 500 to 1,000 calories per day. With Medication, the amount of weight loss can potentially increase depending on the medication and how an individual responds to it. For example:

• Wegovy (Semaglutide): Clinical trials have shown an average weight loss of about 10-15% of body weight over a year. In the first month, weight loss might be more rapid as the body adjusts. For example, if you weigh 200 lbs, you can expect to lose up to 20 lbs to 30 lbs.
• Mounjaro (Tirzepatide): Early results suggest that it might be even more effective than Wegovy, with similar or slightly higher initial monthly weight loss expected (15-20% of body weight). For example, if you weigh 200 lbs, you can expect to lose up to 30 lbs to 40lbs.
• Ozempic, Saxenda, and Rybelsus: While effective, the expected weight loss in the first month would likely align more closely with the general guideline of 1-2 pounds per week, possibly slightly higher depending on individual factors (5-10% of body weight). For example, if you weigh 200 lbs, you can expect to lose up to 10lbs to 20lbs.

Keep in mind that weight loss is usually fastest at the start of any new diet or medication, partly from water weight. Sustainable loss is a slow grind that takes patience and consistency.

Will I gain the weight back if I stop taking the medication?

If you stop taking the medication, you might gain the weight back, especially if you haven't changed your eating and exercise habits for the long term. A study conducted in 2022 found that people regained two-thirds of the weight lost after they stopped taking Ozempic for a year. Here are the main reasons why this can happen:

• Feeling Hungrier: These medicines often help you feel less hungry. When you stop taking them, you might feel hungrier than before, which can lead to eating more.
• Change in Metabolism: Some of these medicines might also help your body burn calories a bit faster. Without the medicine, your body might not burn calories as quickly, making it easier to gain weight.
• Habits Matter: Losing weight and keeping it off usually means eating healthier and moving more. If you relied only on the medicine without changing your habits, you might find it hard to keep the weight off once you stop the medication.

Side Effects

While some side effects are common across these medications due to their similar mechanisms of action, there are differences worth noting.

Common Side Effects Across Most GLP-1 Agonists:

• Nausea and Vomiting: A common side effect, especially when beginning treatment.
• Diarrhea: Some people may experience gastrointestinal disturbances.
• Constipation: Changes in bowel habits can occur.
• Headache: Some individuals report headaches, especially in the initial stages of treatment.
• Appetite Changes: Decreased appetite is a common and intended effect, but for some, it can be uncomfortable.

Specific Medications:

Ozempic and Rybelsus (Both contain Semaglutide): Similar side effects, including gastrointestinal issues. Rybelsus being an oral medication, may have slightly different absorption dynamics which can influence the side effect profile, potentially offering a slightly different experience in gastrointestinal symptoms compared to injectable Ozempic.

Wegovy (Higher dose Semaglutide): Shares side effects with Ozempic and Rybelsus but may have a higher incidence of gastrointestinal side effects due to its higher dose. This can include more pronounced nausea, vomiting, and diarrhea.

Mounjaro (Tirzepatide): Along with common GLP-1 related side effects, Mounjaro, due to its dual mechanism (GLP-1 and GIP receptor activation), might present a unique side effect profile. Early data suggest a similar range of gastrointestinal side effects, potentially with variations in intensity.

Saxenda (Liraglutide): Shares many common side effects with the other medications listed, with a focus on gastrointestinal disturbances. As a daily injection, the frequency of administration could potentially influence side effect perceptions and management.

Important Considerations:

• Severity and Duration: The intensity and duration of side effects can vary. Many side effects, particularly gastrointestinal ones, tend to decrease in severity over time as the body adjusts to the medication.
• Injection Site Reactions: For injectable medications (Ozempic, Wegovy, Mounjaro, Saxenda), there can be reactions at the injection site, such as redness or irritation.
• Risk of Thyroid C-cell Tumors: Medications like liraglutide (Saxenda) carry a warning about a potential risk for thyroid C-cell tumors, based on animal studies.

Cost & Insurance

Cash prices change by pharmacy, dose, and dispensing fee. TeleTest now maintains phone-verified Ontario pharmacy pricing in the cost search tool. The latest verified ranges are:

• Ozempic: $258.19 to $282.00 per month for brand, or $88.88 to $103.53 for generic semaglutide where available.
• Rybelsus: $354 to $365 per month.
• Mounjaro: $325.67 to $650.00 per month, depending on dose and pharmacy.
• Zepbound: $158.00 to $649.13 per month, depending on dose and pharmacy.
• Saxenda: $450 to $600 per month.
• Wegovy: $431.12 to $492.80 per month.

These ranges come from direct pharmacy calls and include dispensing fees where the pharmacy quoted them. Use the linked cost pages for the current source of truth before filling a prescription.

Provincial coverage depends on the medication and indication. In Ontario, Ozempic and Rybelsus are Limited Use medications for type 2 diabetes, while Wegovy, Zepbound, Saxenda, and weight-loss use of tirzepatide are generally not covered by OHIP. Some private insurance plans such as those through your employer may cover weight-management medication. Here are some steps you can take to find out if your specific plan covers these medications:

• Review Your Insurance Policy: Start by looking at the details of your health insurance policy. Most insurers provide a list of covered medications, also known as a formulary, which you can often find on their website or by calling customer service.
• Contact Your Insurance Provider: To get the most accurate information, call your insurance provider directly. Ask them about coverage for the specific weight loss medication you are considering, such as semaglutide, tirzepatide, or liraglutide. Be sure to inquire about any conditions or criteria that must be met for coverage.

Some insurance plans have specific rules about what medications they will cover based on the conditions for which the drugs were originally approved (On-label vs. Off-label Use) by regulatory agencies, such as Health Canada.

Here's a breakdown of what that means:

• On-label use refers to using a medication for an approved indication. Saxenda, Wegovy, and Zepbound are weight-management products. Ozempic and Rybelsus are semaglutide products primarily approved for type 2 diabetes indications.
• Off-label use involves prescribing a medication for a condition other than its approved indication. Ozempic, Rybelsus, and Mounjaro may be used off-label for weight loss in selected patients, but coverage is less predictable because insurers often follow the approved indication.

Some insurance providers will only reimburse or cover the cost of the medication if you meet the 'on-label' prescribing criteria. This means you may require a diagnosis of diabetes to qualify for Ozempic, or a diagnosis of obesity to qualify for Wegovy. A physician during your consult can help you select the appropriate medication depending on your coverage.

Getting a Prescription in Canada

At TeleTest, we offer same-day appointments for both new prescriptions and renewals. To qualify, your BMI either needs to be greater than 30 or greater than 27 if you have one of the following obesity-related health conditions:

• High Blood Pressure
• High Cholesterol
• Diabetes
• Polycystic Ovarian Syndrome (PCOS)
• Sleep Apnea
• Fatty Liver Disease

Assuming you meet the criteria, getting a prescription is relatively straightforward:

1. Complete a brief intake form and select your preferred medication (if you are not sure which one is right for you, a doctor during your consultation can help you decide.)
2. Complete a messaging consultation (should take less than 3 minutes) to obtain a requisition for blood work.
3. Once we have your bloodwork, there will be a follow up consultation where the doctor will address any questions, side effects, and issue a 3-month prescription.

Since we offer same-day appointments and you can go to the lab right after the initial consult, you can receive your prescription in as little as 24 hours.

Can I switch prescriptions?

Yes, if your original prescription is through another provider or you would like to switch to a different medication, blood work is not required. We simply need proof of your current prescription which can be any of the following:

• A pharmacy receipt
• Prescription box with your health details
• Digital copy of your prescription
• Photocopy of a prior prescription

Which one is right for me?

Effectiveness: Wegovy, with high-dose semaglutide, and Mounjaro (tirzepatide) have shown significant effectiveness in weight loss, potentially more so than Ozempic, Rybelsus, and Saxenda in respective settings.

Administration: Saxenda requires daily injections, while Ozempic, Wegovy, and Mounjaro are weekly. Rybelsus is the only oral option.

Primary Use: Saxenda, Wegovy, and Zepbound are weight-management products. Ozempic, Rybelsus, and Mounjaro are primarily diabetes products that can also cause weight loss in appropriate patients.

Picking the right weight loss medication usually comes down to a few practical things: cost and coverage, how you take it, and how often. Cost and coverage often decide it, since you'll be on the drug for a while. Method of administration matters too: some people are fine with a weekly shot, others won't stick with anything but a pill. And dosing frequency (daily vs. weekly) needs to fit your routine. A good consult tailors the choice to all of these.

FAQ

Are higher dosages of Ozempic available in Canada?

Higher-dose Ozempic formats and stocking vary by pharmacy. In June 2026 pharmacy calls, some pharmacies did not stock a 2 mg pen format and said a 2 mg dose would require two 1 mg pens. Confirm the exact pen format and price with the pharmacy before filling.

See our FAQ for more information on GLP-1 agonists.

Disclaimer: This blog post is intended for educational purposes only and should not be taken as medical advice. Always consult your healthcare provider for personal health concerns.