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I'm already taking a GLP-1. What should I check?

Four checks for anyone in Canada already on semaglutide (Ozempic, Wegovy or a generic), tirzepatide (Zepbound, Mounjaro) or another GLP-1, plus what to read next.

GLP Guidebook teamUpdated 12 Oct 20264 min read14 sourcesWritten from published sources
The short answer

Check four things. First, that a licensed prescriber prescribed it after a proper consultation, and that a licensed pharmacy filled it. Second, that your pen is genuine and not from a recalled lot: check the DIN and lot number. Third, which side effects need a call to your doctor or 811, and which need 911. Fourth, plan regular reviews with your prescriber.

Read this page first. It covers the checks that matter once you've started: your prescription, fake pens, side effects and when to review how it's going. At the end, three guides take you further, in order.
On this page
  1. Check your prescription
  2. Check your pen is genuine
  3. Side effects to watch
  4. Your reviews
  5. What to read next
  6. Sources

1. Did my prescription come the right way?

All GLP-1 medicines are prescription drugs in Canada. That means a family doctor, nurse practitioner or other licensed prescriber, after a proper consultation, and a licensed pharmacy to fill it.

A doctor who sees you online must meet the same standard of care as in person, including when prescribing, and consider whether you need a physical exam.2 Health Canada says to buy prescription drugs only from a licensed pharmacy.1

Pharmacies are licensed by your province's regulator. In Ontario, for example, every pharmacy must be licensed by the Ontario College of Pharmacists, which has a public register.6

Red flags

  • You never spoke to anyone, only filled in a form.2
  • "No prescription needed", or a seller with no pharmacy licence. Health Canada says fake sellers can misuse official logos and fake endorsements.1
  • A "compounded" version, or a powder you mix yourself. Health Canada doesn't allow routine compounding of semaglutide.4
  • "Research peptides" such as tirzepatide or retatrutide sold online. Health Canada says these are illegal; retatrutide isn't approved in Canada.3

2. Is my pen genuine, and not recalled?

Check the DIN and the lot number. Fake GLP-1s are sold in Canada, and some genuine generic lots were recalled in 2026.

  • The DIN. Every approved product has an 8-digit Drug Identification Number on the label. Look it up in Health Canada's Drug Product Database.1
  • Fakes. Health Canada warns about fake or unauthorized Ozempic and Mounjaro sold in stores and online (advisory updated January 2026).1
  • Recalls, August 2026. Some lots of Dr. Reddy's Semaglutide Injection (an impurity, and one lot with a 4 mg pen labelled as 2 mg) and one lot of Apo-Semaglutide (a pen that could show and deliver 2 mg instead of 0.25 or 0.5 mg) were recalled. Health Canada advised talking to your healthcare provider before stopping.5

Check the lot number on your pen and box against the recalls site (recalls-rappels.canada.ca). If anything looks or works differently from usual, show it to your pharmacist, and report a suspect product to Health Canada.11 Guide 6 covers fakes and recalls.

Don't stop or switch on your own. If you're worried about your pen, ask your prescriber or pharmacist what to use instead and how to restart. Never use a pen that has frozen.12

3. Which side effects should I watch for?

Stomach upsets are common early on and usually fade.7 A few symptoms need help fast.

Get help now: call 911 or go to an emergency department if you have:
  • Possible pancreatitis (an inflamed pancreas): severe stomach pain that won't go away, sometimes spreading to your back, with or without vomiting.8
  • Signs of a serious allergic reaction: swelling of your face, lips, tongue or throat; trouble breathing; fainting; or a very fast heartbeat.9
  • Signs of very low sugar, like confusion or drowsiness, if you also take insulin or a sulfonylurea (an older diabetes tablet such as gliclazide).9
If you think you injected too much, call a poison centre on 1-844-POISON-X (1-844-764-7669).14
Call your doctor or prescriber soon, or 811 for advice, if you have:
  • Possible gallbladder problems: pain in the upper stomach, yellow skin or eyes, fever, or pale clay-coloured stools.9
  • Vomiting or diarrhea that stops you keeping fluids down.9
  • Changes in your vision, if you have diabetes.9
  • Possible thyroid problems: a lump in your neck, hoarseness, or trouble swallowing.8
811 reaches a nurse in most provinces and territories (Info-Santé 811 in Quebec); Manitoba, the Northwest Territories and Nunavut use other numbers.10

Report a side effect. Tell your prescriber first. You can also report it yourself to Health Canada's Canada Vigilance Program, online or by phone on 1-866-234-2345.11

On tirzepatide (Zepbound, Mounjaro) and taking the contraceptive pill? The Canadian guideline advises switching to a non-pill method, or adding a barrier method such as condoms, for 4 weeks after starting and for 4 weeks after each dose increase.12 Having an operation or sedation? Tell your care team you take a GLP-1.12

4. When should I review how it's going?

Regularly, with your prescriber, and especially while the dose is still going up.

The Canadian obesity guideline notes that regulators have traditionally advised stopping if 5% of your weight hasn't gone after 3 months on a full dose. It adds that real health gains, such as better blood sugar or blood pressure, can come whatever the amount of weight lost, and recommends long-term use when the medicine is working.12 For someone who started at 90 kg (198 lb), 5% is 4.5 kg (about 10 lb).

If you have diabetes, Diabetes Canada says A1C (a blood test of your average sugar over 2 to 3 months) should be checked at least every 3 months while you're not at target or your treatment is changing.13

Paying yourself? Ask your prescriber whether your private plan covers it, and check whether its rules change after the first year.

Take this to your review

  • The brand, strength and dose you're on, and the DIN and lot number
  • Your weight and waist notes since you started
  • Any side effects, and when they happen
  • All your other medicines, including natural health products and anything bought online
  • Your questions about the long term, coverage and stopping
Life on a GLP-1StoppingBefore you see a doctor

What to read next, in order

These three guides go deeper. Each one ends with a link to the next, so you can read them one after another.

  1. 1Side effects and risksGuide 5 of 9DecideWhat's normal in the first weeks, what isn't, and what helps.
  2. 2Life on a GLP-1Guide 8 of 9Live with itEating enough protein, missed doses, storing pens and travelling, Ramadan and fasting.
  3. 3Stopping and the long termGuide 9 of 9Live with itWhat happens if you stop, and how to plan for the long term.
Was this page easy to understand?

Sources

  1. Health Canada. Thinking about buying GLP-1 drugs like Ozempic or Mounjaro? Beware of fake or unauthorized products (advisory RA-81518: licensed pharmacy; 8-digit DIN; misused logos and fake endorsements), updated 21 January 2026. recalls-rappels.canada.ca
  2. College of Physicians and Surgeons of Ontario. Virtual Care policy, updated June 2022 (same standard of care, including prescribing; consider whether a physical examination is required). cpso.on.ca
  3. Health Canada. Unauthorized injectable peptide drugs seized and sold in Canada (advisory), 1 August 2025. recalls-rappels.canada.ca
  4. Alberta College of Pharmacy. Unauthorized compounding of semaglutide-containing products is not permitted (Health Canada policy POL-0051). 10 June 2025. abpharmacy.ca
  5. Health Canada recalls: Semaglutide Injection (Dr. Reddy's) incorrect pen in package, 12 August 2026; out-of-specification impurity, 27 August 2026; Apo-Semaglutide incorrect dose display, 27 August 2026. impurity · pen · Apo
  6. Ontario College of Pharmacists. About Find a Pharmacy or Pharmacy Professional (every pharmacy operating in Ontario must be licensed by the College). ocpinfo.com
  7. Wharton S et al. Gastrointestinal tolerability of once-weekly semaglutide 2.4 mg in adults with overweight or obesity (STEP 1–4). Diabetes, Obesity and Metabolism 2022;24:94–105. DOI
  8. Novo Nordisk. Wegovy (semaglutide) US prescribing information, revised June 2026: sections 5.1 (thyroid), 5.2 (pancreatitis). (US label.) PDF
  9. Novo Nordisk. Ozempic (semaglutide) injection, US prescribing information and Medication Guide, revised May 2026: allergic reactions, hypoglycemia, gallbladder disease, retinopathy, dehydration. (US label.) PDF
  10. Heart and Stroke Foundation of Canada. Medical services by phone (811 in most provinces and territories; other numbers in Manitoba, the Northwest Territories and Nunavut). Checked 12 October 2026. heartandstroke.ca
  11. Health Canada. Adverse reaction and medical device problem reporting (Canada Vigilance Program; online, 1-866-234-2345). canada.ca
  12. Pedersen SD et al. Canadian Adult Obesity Clinical Practice Guideline: Pharmacotherapy for Obesity Management in Adults, 2025 update. Obesity Canada, Version 3, 11 August 2025 (contraception, anesthesia, long-term use, traditional 5% check); Wegovy and Zepbound Canadian product monographs (do not use if frozen). obesitycanada.ca (PDF) · Wegovy PM · Zepbound PM
  13. Diabetes Canada Clinical Practice Guidelines Expert Committee. Monitoring glycemic control (chapter 9). Can J Diabetes 2018;42(Suppl 1):S47–S53. guidelines.diabetes.ca
  14. Health Canada. Canada launches new toll-free 1-844-POISON-X number for poison centres. 20 March 2023. canada.ca

Last checked 12 Oct 2026 · Next review due Jan 2027

How this page was made. Written by the GLP Guidebook team from the sources above: Health Canada advisories and recalls, Canadian and US drug labels, the Canadian obesity and diabetes guidelines, and provincial regulators. It's general information, not medical advice. Talk to your family doctor, nurse practitioner or pharmacist before starting, stopping or changing any medicine. In an emergency, call 911. How we write