Monthly Weight Loss Injections: Are Longer-Acting GLP-1s Coming?

Monthly weight loss injections are moving from an appealing idea into late-stage drug development, but they are not a current replacement for the weekly GLP-1 injections people use today. The clearest programs to watch are maridebart cafraglutide (MariTide) and berobenatide. Both remain investigational, and neither has FDA approval for chronic weight management. [3] [4] [5] [6]

The short answer

Yes, researchers are testing injections intended for every-four-week maintenance dosing. MariTide has peer-reviewed phase 2 results and a phase 3 obesity study. Berobenatide has company-reported phase 2b results and an active phase 3 program. That progress matters, but phase 3 testing, regulatory review, manufacturing, labeling, and real-world coverage still stand between a promising study and an available monthly prescription. [3] [4] [5] [6]

If you want the foundation first, read Yucca’s plain-language guide to how GLP-1 medications work. For the medicines already used weekly, our semaglutide versus tirzepatide comparison keeps the approved options separate from this future-looking pipeline.

What “monthly” actually means

In these development programs, monthly generally means an injection about every four weeks after an initial treatment plan. It does not mean that every candidate starts monthly on day one. Berobenatide’s phase 2b program, for example, used weekly dose escalation before the monthly maintenance phase. MariTide’s phase 2 trial included every-four-week and every-eight-week schedules, while the larger phase 3 MARITIME-1 study is designed to evaluate the investigational medicine over 72 weeks. [3] [4] [5]

That distinction matters because the dosing interval is only one part of treatment. The starting dose, escalation plan, drug exposure between injections, side-effect profile, stopping rules, and follow-up schedule can all differ. A medication that remains active longer may reduce calendar reminders, but it may also require a carefully designed ramp-up rather than an immediate once-monthly routine.

MariTide: the strongest published monthly signal

Maridebart cafraglutide, usually shortened to MariTide, combines GLP-1 receptor agonism with GIP receptor antagonism in an antibody-peptide conjugate. In a randomized phase 2 trial, 592 adults received MariTide or placebo: 465 participants had obesity without diabetes and 127 had obesity with type 2 diabetes. The trial tested several doses and schedules, including monthly administration. [3]

At 52 weeks, the treatment-policy analysis reported mean weight changes of 12.3% to 16.2% across MariTide groups without diabetes, compared with 2.5% for placebo. In participants with type 2 diabetes, the reported range was 8.4% to 12.3%, compared with 1.7% for placebo. These are group averages from a phase 2 trial—not a forecast for an individual and not evidence that MariTide outperforms semaglutide or tirzepatide. [3]

Gastrointestinal events were common. The published phase 2 results say those events were less frequent with a lower starting dose and dose escalation, which is one reason the path to monthly maintenance still includes careful dose design. The study reported no unexpected safety signal, but phase 2 is not the final safety record. [3]

The phase 3 MARITIME-1 registry describes a randomized, placebo-controlled 72-week study in adults with obesity or overweight without type 2 diabetes. Its existence shows that the program has advanced; it does not establish approval, a launch date, or the final label. [4]

Berobenatide: promising, with an important evidence caveat

Berobenatide, also identified as PF-08653944, is an ultra-long-acting GLP-1 receptor agonist being developed for monthly maintenance dosing. Pfizer’s June 2026 phase 2b update described weekly titration followed by once-monthly dosing and said the results supported advancement into phase 3. Because this public evidence is a manufacturer announcement rather than a full peer-reviewed paper, it is best read as preliminary and company-reported. [5]

The phase 3 VESPER-6 registry lists a randomized study in people with obesity or overweight without type 2 diabetes. The registered trial is the evidence-producing next step; it is not proof that the medicine will ultimately be approved, how it will compare with existing options, or what insurers would cover. [6]

How monthly candidates differ from today’s weekly injections

What could improve—and what may not

The obvious potential advantage is fewer injection days: roughly 13 every-four-week doses in a year instead of 52 weekly doses. That may simplify routines for some people. But convenience is not the same as adherence, persistence, affordability, or clinical superiority. Those outcomes need their own evidence.

A longer interval could also change how patients and clinicians handle side effects. With any long-acting medicine, the relevant question is not simply “How often do I inject?” but “How does exposure build, how long does it persist, and what is the plan if symptoms occur?” MariTide’s phase 2 experience with lower starting doses and escalation reinforces why the ramp-up plan matters. [3]

Cost and coverage are especially unknowable before approval. A monthly product could reduce the number of devices shipped, yet price, pharmacy-benefit rules, prior authorization, supply, and employer coverage would still determine access. No responsible forecast can turn an investigational dosing schedule into an out-of-pocket estimate today.

A realistic timeline

Phase 3 studies are designed to answer bigger questions in larger groups over longer periods. After that come data analysis, regulatory submission if the sponsor proceeds, FDA review, manufacturing readiness, and commercial decisions. Trial registries can show planned study milestones, but they are not launch calendars and dates can change. [4] [6]

The most accurate way to follow progress is to look for completed phase 3 results, peer-reviewed publication, and an FDA decision—not social posts that call a study medicine “available soon.” Even strong average weight loss in phase 2 cannot predict approval or the final population, warnings, dosing instructions, and monitoring requirements.

What to do if weekly dosing is difficult now

Tell your prescriber what is actually hard: remembering the day, side effects around each dose, travel, storage, shortages, or cost. Those problems require different solutions. A reminder system may help with scheduling; a clinician may adjust an approved titration plan for tolerability; a pharmacy team may help with supply; an insurance review may address coverage. Waiting for a monthly drug is not a safe substitute for solving a current treatment problem.

Do not space weekly injections farther apart, combine doses, or use an unapproved product marketed as a monthly GLP-1 without clinician guidance. The current Wegovy injection label and FDA’s Zepbound approval information specify once-weekly administration. [1] [2]

The bottom line

Longer-acting weight loss injections are genuinely advancing, and monthly maintenance could eventually become another treatment format. Today, however, MariTide and berobenatide are research programs—not prescriptions. MariTide has the stronger published phase 2 evidence; berobenatide’s cited phase 2b details are company-reported; both still need phase 3 evidence and regulatory review. [3] [4] [5] [6]

For now, judge a medication by the whole treatment—not just the number of injections. Effectiveness, safety, titration, persistence, availability, and cost all matter. Keep a current weekly medication on its prescribed schedule, and revisit monthly options only if they complete testing and receive an approval that fits your clinical situation.