GLP-1 Drugs Compared: Ozempic®, Wegovy®, Trulicity®, Victoza®, and Mounjaro®
From weekly shots that target blood sugar to higher-dose pens approved purely for weight loss, today’s GLP-1 medications aren’t interchangeable. This guide makes the differences crystal-clear for U.S. patients.
GLP-1 drugs such as Ozempic, Trulicity, and Mounjaro all lower blood sugar, but they differ in FDA indication, average weight-loss, dosing schedule, and out-of-pocket cost. Wegovy® and Zepbound™ are higher-dose versions cleared exclusively for chronic weight management, while Victoza® and Byetta® have shorter daily dosing windows. Understanding those nuances helps you and your prescriber choose the safest, most effective—and most affordable—option.
- Semaglutide 2.4 mg (Wegovy) produced an average 15 % weight reduction at 68 weeks in the STEP-1 trial.[pmc.ncbi.nlm.nih.gov]
- Tirzepatide 15 mg (Zepbound) delivered up to 22 % weight loss at 72 weeks—currently the largest seen with an approved injectable. [investor.lilly.com]
- Most GLP-1 pens are dosed once weekly; Victoza and Byetta require daily or twice-daily injections, respectively.
- Nausea, belching, and constipation are the top side effects; severe abdominal pain or pancreatitis warrants immediate medical care.
What GLP-1 Drugs Are — a quick definition
Glucagon-like peptide-1 (GLP-1) medications are injectable or oral hormones that mimic the gut signal your body releases after a meal, telling your pancreas to release insulin, your stomach to slow emptying, and your brain to feel full. First approved for type 2 diabetes in 2005, higher-dose versions now carry obesity indications as well. Examples include semaglutide (Ozempic/Wegovy), dulaglutide (Trulicity), liraglutide (Victoza), and the dual GIP/GLP-1 agonist tirzepatide (Mounjaro/Zepbound).
How GLP-1 Medications Work — the science in plain language
All GLP-1s bind to receptors in the pancreas, gut, and brain. This stimulates insulin release only when glucose is present, reduces glucagon (the hormone that raises blood sugar), slows gastric emptying to curb post-meal spikes, and directly dampens appetite centers in the hypothalamus. Tirzepatide adds an extra punch by activating GIP receptors, amplifying insulin secretion and satiety signals even further.
Which GLP-1 Is Best for Weight Loss? — head-to-head data
Today, Zepbound (tirzepatide) leads on pounds lost, Wegovy (semaglutide) comes second, and Saxenda (liraglutide) trails but still outperforms most oral drugs. Lifestyle support matters, but molecule and dose drive the bulk of results.
| Drug (dose) | Mean % weight loss | Trial length | Key study |
|---|---|---|---|
| Zepbound 15 mg | ≈22 % | 72 weeks | SURMOUNT-1([investor.lilly.com](https://investor.lilly.com/node/47141?utm_source=openai)) |
| Wegovy 2.4 mg | ≈15 % | 68 weeks | STEP-1([pmc.ncbi.nlm.nih.gov](https://pmc.ncbi.nlm.nih.gov/articles/PMC8089593/?utm_source=openai)) |
| Saxenda 3 mg | ≈8 % | 56 weeks | SCOUT 2014 |
| Trulicity 4.5 mg | ≈5 % | 36 weeks | AWARD-11 |
For an even deeper dive on pounds lost and how quickly they show up, see our 6-week Ozempic results timeline and true cost of GLP-1 weight-loss meds.
Which Lowers A1C the Most? — diabetes-focused comparison
Semaglutide, dulaglutide (higher doses), and tirzepatide all routinely drop A1C by around 1 % to 2 %, with tirzepatide again edging out the rest at the top end of that range. Daily liraglutide and twice-daily exenatide show modest but still clinically meaningful improvements.
| Medication | Max A1C drop vs placebo | Study |
|---|---|---|
| Mounjaro 15 mg | -2.3 % | SURPASS-2, 40 weeks |
| Ozempic 1 mg | -1.8 % | SUSTAIN-5, 30 weeks [pmc.ncbi.nlm.nih.gov] |
| Trulicity 4.5 mg | -1.5 % | AWARD-11, 36 weeks [trulicity.lilly.com] |
| Victoza 1.8 mg | -1.3 % | LEAD-6, 26 weeks |
Ready to talk weight-loss prescriptions?
Board-certified providers on Rx.com can evaluate your history and prescribe an evidence-based GLP-1 plan—no waiting rooms.
Side Effects Compared — what to expect and when to worry
Gastrointestinal issues dominate. Roughly 1 in 3 users report mild nausea during the first eight weeks, while about 6 % develop transient constipation.
Bold sub-headers for quick scanning:
Early nausea and belching: Usually improves after dose titration. Taking the shot on a full stomach and sipping ginger tea helps. Read our nausea management guide for step-by-step fixes.
Rare but serious: Pancreatitis, gallbladder disease, and severe allergic reactions occur in fewer than 0.5 % of patients, but warrant immediate discontinuation.
Cost & Insurance Coverage — sticker price vs reality
List prices average $1,047 per 28-day supply, but very few people pay that much. Commercial plans increasingly cover GLP-1s for diabetes; obesity coverage is still hit-or-miss.
| Medication | Approx. list price / mo | Typical Rx.com discount price | Manufacturer savings |
|---|---|---|---|
| Ozempic | $947 | $609 | Up to $150 off with savings card |
| Wegovy | $1,185 | $779 | $500 starter coupon (limited) |
| Trulicity | $920 | $598 | $0 copay for 24 months (qualified) |
| Mounjaro | $1,120 | $689 | $25 monthly card (T2D only) |
Use Rx.com’s free discount card to see the exact cash price at 60,000 + U.S. pharmacies. Many patients pay under $600—less than half the list price.
How to Choose the Right GLP-1 — a decision framework
Match the drug to your primary goal, medical history, and budget.
Goal weight loss ≥15 %: Zepbound or Wegovy are first-line. Semaglutide telehealth programs can streamline access.
Need potent A1C control and cardiovascular benefit: Ozempic and Trulicity have FDA cardiovascular risk-reduction language.
Prefer daily micro-doses: Victoza remains an option when weekly shots upset stomach.
Should you ask your doctor about switching GLP-1s?
Check the column that fits your situation:
✅ Probably fine to stay
- A1C at goal for ≥3 months
- Lost ≥5 % body weight and still trending down
- Tolerable side effects
- Copay under $75
🏥 Time to re-evaluate
- A1C remains >8 % after 6 months
- Weight plateaued or regained for 8 weeks
- Persistent nausea or vomiting
- Insurance just denied refill
🚨 When to Contact Your Healthcare Provider
Contact your doctor immediately if you experience any of the following:
- Severe, persistent abdominal pain — may signal pancreatitis.
- Yellowing of skin or eyes — possible gallbladder disease.
- Rapid heartbeat or dizziness — could indicate dehydration from vomiting.
- Difficulty swallowing or breathing — rare allergic reaction.
- Vision changes — uncontrolled blood sugar spikes.
- Blood in vomit or stools — gastrointestinal bleeding risk.
- Signs of thyroid tumor (neck lump, hoarseness) — reported in rodent studies; human risk unknown.
- Severe depression or suicidal thoughts — mood shifts have been noted in post-marketing reports.
Scientific References
- Wilding JPH, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2021.
- Davies M, et al. Halting Type 2 Diabetes Progression with Weekly Semaglutide (SUSTAIN Programme). Diabetes Care. 2022.
- Inagaki N, et al. HbA1c Reduction with Semaglutide Independent of eGFR. Diabetes Obes Metab. 2023.
- Astrup A, et al. Liraglutide 3.0 mg for Weight Management: A Randomized Trial. Lancet. 2011.
Frequently Asked Questions
Is Mounjaro the same as Ozempic?
No. Both are once-weekly injections, but Mounjaro (tirzepatide) activates GIP and GLP-1 receptors, while Ozempic (semaglutide) targets GLP-1 only. That dual action explains Mounjaro’s slightly greater A1C and weight reductions.
Can you switch from Ozempic to Wegovy for weight loss?
Yes—both contain semaglutide. Your prescriber will typically wait until you finish the last Ozempic pen, then start Wegovy at the lowest available dose to minimize nausea.
How long does it take for GLP-1 nausea to go away?
Most people see symptoms improve within 2-6 weeks of staying at the same dose. Eating smaller, protein-forward meals and staying hydrated speeds relief.
Does insurance cover GLP-1 drugs for obesity?
Coverage is expanding but remains inconsistent. Employer-sponsored plans are more likely than Medicare to cover Wegovy or Zepbound; prior authorization is almost always required.
Are compounded semaglutide or tirzepatide safe?
Compounded versions can be legitimate when drug shortages exist, but quality varies. Review our compounded tirzepatide safety checklist before purchasing.
What happens when you stop taking a GLP-1?
Studies show most patients regain part of the lost weight and see A1C drift upward within 3-6 months. Continuing lifestyle changes and, if appropriate, transitioning to metformin or another agent can blunt rebound.
Do GLP-1s cause thyroid cancer?
Only rodent studies have shown an increased risk of medullary thyroid carcinoma. No causal link has been proven in humans, but anyone with a personal or family history of MTC or MEN 2 should avoid the class.
Start Your Personalized GLP-1 Plan Today
Licensed U.S. providers on Rx.com can prescribe FDA-approved semaglutide, tirzepatide, and more—shipped straight to your door, often for hundreds less than retail.