GLP-1 Agonists: Frequently Asked Questions

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Curious about the science behind today’s most talked-about diabetes and weight-management treatments? Our new, four-part blog series on GLP-1 Agonists will break down everything you need to know — from how these drugs work, to their real-world results, side effects, and what’s coming next in the pipeline. Today, we’re taking a look at some of the most frequently asked questions about GLP-1s, and providing answers sourced from some of the most reputable online publications.

Q: Which GLP-1 drug/molecule causes the most weight loss?
A: Current evidence suggests tirzepatide (Zepbound for obesity) is among the most effective for weight loss, with higher average weight loss compared to many others. Semaglutide (in its obesity dose, i.e. Wegovy) is also very effective. But individual results vary.

Q: Can I use a GLP-1 drug for weight loss even if I don’t have type 2 diabetes?
A: Yes — but only some are approved for that use. For example, Wegovy (semaglutide at obesity-dose), Saxenda (liraglutide higher dose) or Zepbound. Others are used “off-label” by some clinicians, but off-label use means less trial data in that setting, and possibly more out-of-pocket cost.

Q: What about oral GLP-1s? Are they as good?
A: There is an oral version of semaglutide (Rybelsus) approved for T2DM. It is less potent (or at least less weight loss in many studies) compared to injectable GLP-1s at high obesity doses. Also, the oral drug has stricter administration requirements (e.g. empty stomach, water only, wait before food/other meds) to ensure absorption.

Q: What are typical side effects of taking GLP-1s & how can they be reduced?
A: Nausea, vomiting, diarrhea, or constipation are the most common side effects, especially at the start of dosing or during dose increases. Tactics to reduce them include: starting at low dose and titrating slowly; taking with small meals; adjusting diet (more bland / lower fat temporarily); staying hydrated; maybe dividing doses (depending on formulation). If side effects are severe or persistent, it would be advisable to discuss this with provider about dose adjustment or switching agent.

Q: How long should I expect to continue treatment once initiated?
A: Often long-term (chronic) therapy is needed if the condition (e.g. obesity, diabetes) is chronic. Sometimes people might try a course, lose weight, then maintain on a lower dose or possibly discontinue under medical supervision, but weight usually rebounds if lifestyle changes or therapy is stopped. For T2DM, often therapy is ongoing. Also, benefits (like cardiovascular risk reduction) are seen over longer duration.

Q: Will insurance / public health cover these?
A: It depends heavily on where you live, the specific drug & indication, the healthcare system, and your insurance plan. Some cover diabetes indications more readily; obesity indications are often more restricted (e.g. require certain BMI thresholds, comorbidity requirements). Co-pays or out-of-pocket cost may be high. Assistance programs sometimes exist.

Q: Are there drug interactions or safety issues?
A: Yes. Because they slow gastric emptying, they may affect absorption of oral medications. Also, risk of hypoglycemia is increased if combined with other glucose-lowering agents (especially insulin, sulfonylureas). Watch for pancreatitis symptoms. Use caution in people with severe renal impairment or GI disorders. Also, pregnancy/lactation status should be considered (usually avoided unless benefit clearly outweighs risks).

Q: How soon will I see effects (on sugar, weight)?
A: Glucose improvements can often be seen within days to weeks. HbA1c reductions usually over 3 months. Weight loss tends to be gradual over months; more significant weight loss typically requires staying on the appropriate maintenance dose for many weeks (often 16-68 weeks or longer in the obesity trials).

Q: Can I switch from one GLP-1 to another?
A: Yes, sometimes. If one is poorly tolerated or not achieving goals, switching may help. But need to consider dosing equivalency/titration, the indication, and risk of side effects. This should be done under medical supervision.

Q: What about newer drugs / what’s coming?
A: There is a pipeline of next-generation agents: dual or triple agonists (e.g. GLP-1 + GIP, or GLP-1 + glucagon + GIP), with more potent weight loss effects and possibly better safety/tolerability. Also more oral options are being developed, and many are still in various trial phases.

Thanks for reading our final article in our series highlighting GLP-1 agonists! If you enjoyed this article and haven’t yet checked out the rest of the series, you can click the following link to find all of our original content on this subject: https://joinastudy.ca/canadian-health-blog/

Sources

https://my.clevelandclinic.org/health/treatments/13901-glp-1-agonists

https://www.canada.ca/en/health-canada/services/drugs-health-products/medeffect-canada/health-product-infowatch/december-2024.html

https://pubmed.ncbi.nlm.nih.gov/26371721/

https://www.endocrinologyadvisor.com/ddi/glp-1-agonists/

https://hopkinsdiabetesinfo.org/medications-for-type-2-diabetes-glp-1-agonists/

https://www.ncbi.nlm.nih.gov/books/NBK551568/

https://www.ncbi.nlm.nih.gov/books/n/rc72848269830370/

https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/drug-shortages/information-consumers/supply-notices/ozempic.html

https://www.practicenursing.com/content/clinical/glp-1-receptor-agonists-and-their-role-in-managing-type-2-diabetes

https://www.drugs.com/medical-answers/glp-1-drug-best-weight-loss-3579236/

https://www.primetherapeutics.com/en/glp-1-pipeline-update-november-2024