Semaglutide vs Tirzepatide vs Retatrutide
Semaglutide vs tirzepatide vs retatrutide in 2026: weight-loss results, side effects, cost, and which GLP-1 is right for you — plus the new oral option, orforglipron.
Medical disclaimer: This is general education, not medical advice. These are prescription medications with serious potential side effects. Only a licensed clinician can decide what’s right for you. Last reviewed: June 27, 2026.
Disclosure: Some links to telehealth providers may be affiliate links — if you start a program through them, we may earn a commission at no extra cost to you. We only recommend licensed, prescription providers.
If you’re comparing the big GLP-1 weight-loss drugs in 2026, here’s the one-line version: tirzepatide currently produces the most weight loss among approved options, semaglutide has the deepest track record (including heart-health data), retatrutide is the most powerful but isn’t approved yet, and orforglipron is the new approved pill for people who don’t want injections. Below is the detail behind each.
Quick comparison
| Drug | Brand(s) | Class | Avg. weight loss | Route | 2026 status |
|---|---|---|---|---|---|
| Semaglutide | Ozempic, Wegovy, Rybelsus | GLP-1 | ~15–17% | Weekly injection (or daily pill) | FDA-approved |
| Tirzepatide | Mounjaro, Zepbound | GLP-1 + GIP | ~21–23% | Weekly injection | FDA-approved |
| Retatrutide | (none yet) | GLP-1 + GIP + glucagon | ~24–28% in trials | Weekly injection | Not approved (Phase 3) |
| Orforglipron | Foundayo | GLP-1 (oral) | ~11–13% | Daily pill | FDA-approved (Apr 2026) |
Semaglutide: the proven benchmark
Semaglutide (Ozempic for diabetes, Wegovy for weight loss, Rybelsus as a pill) is the drug that started the boom. In trials it produced roughly 15–17% average weight loss, and — uniquely — it has cardiovascular outcome data showing it lowers the risk of heart events in certain patients. If you want the option with the longest real-world track record and proven heart benefits, semaglutide is it. The trade-off: it’s no longer the most powerful for pure weight loss.
Tirzepatide: the strongest approved option
Tirzepatide (Mounjaro for diabetes, Zepbound for weight loss) hits two hormone receptors (GLP-1 and GIP) instead of one, and the extra mechanism shows up in the results: about 21–23% average weight loss. In a head-to-head trial, tirzepatide beat semaglutide (roughly 22% vs. 15% weight loss). It may also cause somewhat fewer stomach side effects than an equivalent dose of semaglutide. For most people whose goal is maximum weight loss from an approved drug today, tirzepatide is the front-runner.
Retatrutide: the most powerful — but not approved yet
Retatrutide is the one generating the biggest headlines. It’s a triple agonist (GLP-1 + GIP + glucagon), and in its Phase 3 program it produced around 28% average weight loss at 80 weeks — the largest figure ever reported in a late-stage trial of this drug class.
The catch: retatrutide is not FDA-approved. As of mid-2026 it’s still in Phase 3 trials, with the manufacturer expected to file for approval around late 2026 — meaning a realistic approval timeline of 2027 or later. Anything sold as “retatrutide” online right now is an unapproved, gray-market research chemical, and the FDA has issued warning letters to sellers. See our guide to peptide legality for why that matters.
Orforglipron: the new daily pill
Approved April 1, 2026, orforglipron (Foundayo) is the first oral small-molecule GLP-1 — a once-daily pill with no food or water timing restrictions. Its ~11–13% average weight loss is below the top injectables, but for people who won’t or can’t inject, a convenient pill is a meaningful new option.
Side effects (they share a class profile)
All of these drugs share the GLP-1 side-effect profile:
- Most common: nausea, vomiting, diarrhea, constipation — usually worst when starting or increasing the dose, and the leading reason people quit.
- Less common but serious: gallbladder problems, pancreatitis, dehydration-related kidney strain.
- Muscle loss: a meaningful share of the weight lost can be muscle — resistance training and adequate protein matter. See how to avoid muscle loss on GLP-1s.
- Boxed warning: a thyroid C-cell tumor warning (seen in rodents, unconfirmed in humans); these drugs are not for people with a personal/family history of medullary thyroid cancer or MEN 2.
How to choose
- Maximum weight loss, approved today → tirzepatide.
- Longest track record + heart-health data → semaglutide.
- Prefer a pill over a needle → orforglipron (oral) or oral semaglutide (Rybelsus).
- Chasing the biggest possible result → retatrutide is the one to watch, but it isn’t approved — don’t buy gray-market versions.
The right choice depends on your medical history, insurance, and goals — which is a conversation for a licensed prescriber.
Cost & how to get a prescription
Brand-name GLP-1s are expensive and insurance coverage varies widely. Legitimate telehealth programs typically run ~$130–$300/month and connect you with a licensed clinician who can prescribe FDA-approved options. Compare reputable, prescription-based providers in our GLP-1 telehealth comparison. Avoid any site selling “compounded” or “research” GLP-1s without a prescription — that’s the gray market, and it’s both riskier and increasingly targeted by the FDA.
Frequently asked questions
Which is better for weight loss, semaglutide or tirzepatide? In a head-to-head trial, tirzepatide produced more weight loss (~22% vs ~15%). Semaglutide has more cardiovascular outcome data.
Is retatrutide available in 2026? No. It’s still in Phase 3 trials and not FDA-approved. Products sold online as “retatrutide” are unapproved and unregulated.
Is there a GLP-1 pill? Yes — oral semaglutide (Rybelsus) and the newly approved orforglipron (Foundayo), the first small-molecule GLP-1 pill.
Do you keep the weight off after stopping? Studies show significant weight regain after stopping GLP-1s, which is why they’re generally treated as long-term therapy. Discuss a plan with your clinician.
Keep reading
- Are peptides legal in 2026? FDA status explained
- Best GLP-1 telehealth providers compared
- How to avoid muscle loss on GLP-1s
Primary sources: SURMOUNT and STEP trial data, Eli Lilly’s retatrutide (TRIUMPH) program, and FDA approval records for orforglipron/Foundayo. Reviewed and updated as new trial and approval data emerge.