Next-Gen Obesity Drugs Compared: The 2026 Pipeline

The Obesity Drug Pipeline in April 2026

Obesity drugs are changing faster than ever. Two years ago, semaglutide (Wegovy) and tirzepatide (Zepbound) were the state of the art. Today a new generation of drugs is moving through clinical development, each with its own mechanism, route or dosing schedule aimed at different patient needs.

Below we compare the most advanced next-generation obesity drugs as of April 2026: how they work, what efficacy data exist, how far along they are and where they might fit in treatment. All cross-trial comparisons are observational and carry the usual limits of comparing data across different study designs, patient populations and trial lengths.

The Comparison Table

SC = subcutaneous. Weight-loss figures are the highest reported by each sponsor for people who stayed on treatment (efficacy estimand); amycretin’s is a full-adherence estimate. Trials differ in length, population and design.

Retatrutide: The Efficacy Leader

Retatrutide (Eli Lilly) is the only triple hormone receptor agonist in the obesity pipeline, acting on GIP, GLP-1 and glucagon receptors at once. This triple mechanism produces the highest weight loss of any drug in the field today.

Key data. In the Phase 3 TRIUMPH-4 trial, retatrutide 12 mg produced -28.7% mean weight loss at 68 weeks in adults with obesity and knee osteoarthritis (on-treatment estimand). At 9 mg, weight loss was -26.4%. Nearly 40% of participants at 12 mg lost 30% or more of their body weight. The Phase 2 NEJM publication had previously reported up to -24.2% at 48 weeks, and the Phase 3 data confirmed and extended this efficacy.

Differentiating features. Beyond weight loss itself, retatrutide’s glucagon receptor component gives it clear advantages in cutting liver fat (82.4% relative reduction in Phase 2) and raising energy expenditure. No other drug in the pipeline matches these effects except survodutide, which also has glucagon receptor agonism but lacks the GIP component.

Safety considerations. Retatrutide’s side effects include the usual GLP-1 class gastrointestinal effects (nausea 43.2%, diarrhea 33.1% at 12 mg) plus a new dysesthesia signal (20.9% at 12 mg) not seen with other drugs. Discontinuation due to adverse events was 18.2% at 12 mg, though substantially lower (12.1%) in the BMI 35 and above subgroup.

Timeline. Eli Lilly plans to file for approval no later than the first quarter of 2027, with a possible approval decision in late 2027 (Priority Review) or the first half of 2028, and commercial launch in 2028. On October 2, 2026 the FDA ruled that retatrutide is a drug, not a biologic, so the application must be a New Drug Application (NDA); Lilly is contesting the FDA ruling in court and has not said which pathway it will use.

Orforglipron (Foundayo): The First Oral GLP-1

Orforglipron, now marketed as Foundayo, became the first oral non-peptide GLP-1 receptor agonist to receive FDA approval on April 1, 2026. Developed by Eli Lilly, it takes a very different approach to obesity treatment: it delivers GLP-1 receptor agonism through a daily pill instead of an injection.

Key data. In the Phase 3 ATTAIN-1 trial (72 weeks, published in NEJM), the top dose produced -12.4% weight loss among people who stayed on treatment (efficacy estimand) and -11.2% counting everyone randomized (treatment-regimen estimand), against -0.9% and -2.1% on placebo. The trial tested a 36 mg capsule; Lilly says it matches the approved 17.2 mg tablet. These numbers are smaller than the injectable drugs achieve, but they are clinically meaningful and match or beat older injectable GLP-1 agonists.

Differentiating features. Orforglipron’s main advantage is convenience: a daily pill with no injection, no cold chain storage and few rules about when to take it relative to food. It is a small-molecule non-peptide, so it does not need the SNAC absorption enhancer used in oral semaglutide (Rybelsus). The pricing is also notable. As of October 2026, LillyDirect self-pay prices run from $149 a month for the 0.8 mg starting dose to $349 for the 14.5 mg and 17.2 mg doses ($299 if refilled within 45 days), and people with commercial coverage can pay $25 a month with Lilly’s savings card. That is well below the list prices of the injectable drugs.

Clinical position. Foundayo is aimed at the widest possible group of patients: people who prefer pills, people who dislike needles and people looking for an accessible first drug for weight management. It is available now via LillyDirect.

Amycretin: Novo Nordisk’s Oral Challenger

Amycretin is a single molecule from Novo Nordisk that acts on both GLP-1 and amylin receptors. Novo is developing it as a weekly injection and as a daily pill; its 2026 reports use the name zenagamtide.

Key data. The 22% figure comes from the injection, not the pill. In a Phase 1b/2a trial of 125 adults, weekly injected amycretin 20 mg gave an estimated 22.0% weight loss at 36 weeks, assuming everyone stayed on treatment (Novo Nordisk, January 2025). The pill was tested separately: 13.1% at the highest dose after 12 weeks (The Lancet, 2025). Neither result has been repeated in a Phase 3 trial.

Differentiating features. The amylin receptor component adds a mechanism that pure GLP-1 agonists lack. Amylin is a pancreatic peptide released alongside insulin. It suppresses glucagon, slows stomach emptying and promotes fullness through effects on the brain. If the pill form holds up in larger trials, it would add an oral option with a second mechanism.

Caveats. Early-phase data are preliminary. Weight loss often shrinks between Phase 2 and Phase 3 because of larger, more varied patient groups, intent-to-treat analyses and longer trials. The 36-week length is also shorter than typical Phase 3 efficacy endpoints (usually 52-72 weeks). Phase 3 results will show whether amycretin’s early promise holds up as lasting efficacy that matters in real life.

Timeline. Novo reported in August 2026 that its AMAZE Phase 3 program had started. Assuming standard development timelines, FDA submission would not be expected before 2028, with potential approval in 2029.

MariTide: Amgen’s Monthly Injection

MariTide (maridebart cafraglutide, formerly AMG 133) is Amgen’s antibody-based obesity drug. It links a GIP receptor-blocking antibody to GLP-1 receptor agonist peptides, making a single molecule that blocks GIP signaling and activates GLP-1 receptors at the same time.

Key data. In the 52-week Phase 2 trial (NEJM, 2025), people with obesity but without diabetes lost 12.3% to 16.2% of body weight depending on dose, against 2.5% on placebo, counting everyone randomized. Amgen reports up to about 20% among those who stayed on treatment. The drug’s long half-life allows monthly (or potentially less frequent) dosing, and weight loss had not plateaued at 52 weeks.

Differentiating features. MariTide’s main clinical selling point is how rarely it is given. A monthly injection under the skin, if trials bear it out, would be the least burdensome injectable obesity medication. Its anti-GIP mechanism is also different. Retatrutide and tirzepatide activate the GIP receptor; MariTide blocks it. Why weight loss results from both opposite approaches to GIP is still debated by pharmacologists.

Caveats. Phase 2 data are promising but preliminary. The anti-GIP mechanism is new and raises questions about long-term metabolic effects that only longer Phase 3 data can answer. Making antibody-peptide conjugates at scale is more complex and costly than making peptides or small molecules.

Timeline. The Phase 3 MARITIME trials are running; ClinicalTrials.gov lists primary completion for MARITIME-1 in January 2027. Amgen has not disclosed a specific regulatory submission timeline, but market entry before 2028-2029 is unlikely.

Survodutide: The Other Dual Agonist

Survodutide (Boehringer Ingelheim/Zealand Pharma) is a dual GLP-1/glucagon receptor agonist. It shares two of retatrutide’s three receptor targets but has no GIP receptor activity.

Key data. Phase 2 results in obesity showed up to 18.7% weight loss at 46 weeks among people who stayed on treatment. In the Phase 3 SYNCHRONIZE-1 trial (76 weeks, reported April 2026), the top dose gave 16.6% (efficacy estimand) against 3.2% on placebo; in SYNCHRONIZE-2, in people with type 2 diabetes, it gave up to 13.1% against 3.1% (NEJM, October 2026). Survodutide has also shown significant efficacy in MASH (metabolic dysfunction-associated steatohepatitis), with its glucagon component driving large reductions in liver fat, much as retatrutide’s does.

Differentiating features. Survodutide’s glucagon receptor agonism brings metabolic benefits beyond appetite suppression, including higher energy expenditure and direct release of fat from the liver. Its MASH efficacy data are among the strongest in the field and may become its main niche if it cannot match triple agonists on weight loss in obesity.

Caveats. Without GIP receptor agonism, survodutide works through fewer pathways than retatrutide. Phase 3 results will show whether the dual mechanism is enough to compete with triple agonism on weight loss, or whether survodutide will be aimed mainly at liver disease.

Timeline. The obesity readouts are in; MASH and cardiovascular outcome trials are still running. We found no regulatory filing as of October 31, 2026. Submissions could begin in 2027, with potential approval in 2027-2028.

VK2735: Viking’s Early-Stage Contender

VK2735 (Viking Therapeutics) is a GLP-1/GIP dual agonist given by injection under the skin. It drew a lot of attention on the strength of early Phase 2 data.

Key data. Phase 2 results showed about 14.7% weight loss at 13 weeks, a notable result for such a short treatment period. If weight loss kept going at a similar rate over a standard 52-68 week period, the total could rival established drugs.

Differentiating features. Viking is a much smaller biotech than Lilly, Novo and Amgen, which may affect how fast it develops the drug, how much it can make and how widely it can sell it. The 13-week Phase 2 data are promising but are the earliest-stage evidence in this comparison. Viking is also developing an oral version of VK2735, which could give it a choice of forms similar to Eli Lilly’s mix of injectable and oral drugs.

Caveats. The 13-week trial is far shorter than any other data in this comparison. Weight loss curves for GLP-1 agonists usually do not level off until 40-68 weeks, so projecting from 13-week data is unreliable. Phase 3 data are needed to judge where VK2735 fits.

Timeline. Phase 3 trials have started. Because Viking is a smaller company, a regulatory submission may not come until after 2028.

What Differentiates Retatrutide

Among the next-generation drugs, retatrutide stands apart for several reasons:

Highest demonstrated efficacy. At -28.7% in Phase 3, retatrutide has the strongest weight loss data supported by Phase 3-level evidence. No other drug in this comparison has reported results in that range.

Triple receptor mechanism. Retatrutide is the only drug acting on three metabolic hormone receptors at once. The glucagon component raises energy expenditure and cuts liver fat in ways that single agonists and most dual agonists do not.

Liver fat reduction. The 82.4% relative liver fat reduction seen in Phase 2 is among the largest reported for any drug in MASLD/MASH, which could give retatrutide a role in liver disease beyond obesity.

Broadest indication potential. Lilly is developing retatrutide for obesity, type 2 diabetes, OSA, knee OA, cardiovascular outcomes, kidney disease and liver disease, a wider range of uses than any competing pipeline drug.

Tolerability trade-offs. The dysesthesia signal (20.9% at 12 mg) and higher GI side effect rates set retatrutide’s safety profile apart from its competitors. Clinicians will need to weigh these against its efficacy advantage.

How Treatment Is Changing

The variety in the 2026 obesity drug pipeline points to a future where treatment matches the drug to the patient:

For patients who prefer oral treatment or have mild-to-moderate obesity: Orforglipron (Foundayo) is already available and provides a convenient, affordable entry point. Oral amycretin may add another pill option if its Phase 3 results hold up.

For patients needing significant weight loss with weekly injection convenience: Retatrutide, tirzepatide (Zepbound) and survodutide offer strong efficacy with once-weekly dosing. Retatrutide leads on raw efficacy.

For patients who prefer the least frequent dosing: MariTide’s monthly injection could define a new standard for dosing convenience if Phase 3 confirms its efficacy and safety.

For patients with liver disease comorbidity: Retatrutide and survodutide, both with glucagon receptor agonism, have the strongest mechanistic basis and clinical data for liver fat reduction.

This is not a winner-take-all market. More than 100 million adults in the United States alone have obesity, with different clinical needs, preferences and other health conditions. Several effective drugs with different strengths will each find a place.

Frequently Asked Questions

Which next-gen obesity drug produces the most weight loss?

Based on Phase 3 data, retatrutide (Eli Lilly) produces the highest reported weight loss at -28.7% at 68 weeks. However, this comparison is limited because several competing agents have only early-phase data from shorter trials. Injected amycretin (Novo Nordisk) gave an estimated 22.0% at 36 weeks in a Phase 1b/2a trial; the pill form has been tested only for 12 weeks. Phase 3 data from multiple agents are expected throughout 2026-2027 and will provide clearer comparative evidence.

Is orforglipron (Foundayo) better than retatrutide?

These drugs serve different clinical needs and are not directly comparable as “better” or “worse.” Orforglipron (Foundayo) is an FDA-approved oral daily pill producing about 12% weight loss in its Phase 3 trial. As of October 2026 it costs $149 to $349 a month self-pay on LillyDirect, depending on dose, or $25 a month with commercial coverage and Lilly’s savings card. Retatrutide is an investigational weekly injection producing 28.7% weight loss, not yet approved. Orforglipron offers convenience and easy access; retatrutide offers the most weight loss. Both are Eli Lilly products designed for complementary patient populations.

When will retatrutide be available?

Eli Lilly plans to submit the TRIUMPH program data to the FDA no later than the first quarter of 2027. Assuming standard or priority review timelines, an approval decision could come in late 2027 with Priority Review or the first half of 2028 under standard review, with commercial launch in 2028. The pivotal obesity readouts were all reported by July 2026; the timeline now depends on the submission and the FDA review process.

What about CagriSema from Novo Nordisk?

CagriSema (cagrilintide plus semaglutide) is another important pipeline agent, combining a long-acting amylin analog with semaglutide. In REDEFINE 1 (68 weeks) it produced 22.7% weight loss among people who stayed on treatment (20.4% counting everyone). In the head-to-head REDEFINE 4 trial it fell short of tirzepatide 15 mg (20.2% vs 23.6% at 84 weeks, counting everyone). Novo Nordisk filed it with the FDA in December 2025 and expects a decision by late 2026; we found no approval as of October 31, 2026.

Will these new drugs be affordable?

Pricing varies significantly. Orforglipron (Foundayo) launched in April 2026 at $149 a month self-pay for the lowest dose, or $25 a month with commercial coverage and Lilly’s savings card. The injectable drugs have list prices above $1,000 a month (Wegovy’s was $1,349 as of February 2026), though their self-pay prices are lower. Retatrutide pricing has not been announced. Competition in a growing obesity drug market, together with political and regulatory pressure on drug prices, suggests prices may fall as more options arrive, though this is not guaranteed.