Novo Nordisk starts a Phase 3 trial hunting the lowest effective Wegovy pill dose

Novo Nordisk has launched a new late-stage study, called OASIS-5, to test whether lower doses of oral semaglutide, sold as Wegovy in pill form, can still produce meaningful weight loss ^[2]. The trial was registered on the US clinical trials database and is expected to run through 2028 ^[2].

The study will enroll 450 adults who have a body mass index of 30 or higher, or a BMI of 27 with at least one weight-related health condition, and who have a history of unsuccessful weight loss attempts ^[2]. It is a 60-week, randomized, placebo-controlled trial comparing two lower, unspecified doses of the oral pill against a placebo ^[2]. The pill is currently available in 1.5 mg, 4 mg, 9 mg, and 25 mg strengths, with 25 mg as the approved long-term maintenance dose ^[2]. People with diabetes, those with recent large weight swings, or those already on other GLP-1 drugs cannot join the trial ^[2].

Besides weight loss, researchers will track waist circumference and other health markers, along with safety and tolerability data ^[2]. That safety focus matters because, according to the report, many patients already adjust their own doses downward, sometimes without medical guidance, to manage side effects or cost ^[2].

The trial design follows what Novo Nordisk has already observed in the market. At launch, 88% of Wegovy pill volume sold was the lowest 1.5 mg strength, a pattern that chief executive Mike Doustdar interpreted as evidence that most buyers were new to GLP-1 therapy rather than people needing higher doses ^[2]. Doustdar was quoted saying, "People are using low dosages of these products… they just decide on their own," and added that "patients often seek benefits beyond weight loss" ^[2]. Eli Lilly, which sells the rival tirzepatide products Mounjaro and Zepbound, did not respond to questions about whether it is testing lower doses of its own oral obesity drug ^[2].

Why it matters for patients

If a lower dose is proven to still produce meaningful weight loss, it could change what doctors prescribe as a maintenance dose after initial weight loss, rather than automatically pushing patients toward the current 25 mg tier ^[2]. A lower approved dose could also affect self-pay pricing and the amount of drug Novo Nordisk needs to manufacture per patient, which the summary notes changes the arithmetic of supply and cost. For patients already self-adjusting their doses to cut costs or reduce side effects, this trial could eventually generate data on whether that approach is effective and safe, something that has not been rigorously studied until now ^[2].

The trial's design, limited to patients with a history of failed weight loss attempts and excluding those with diabetes or on other GLP-1 drugs, means results may not apply to everyone taking the pill today ^[2]. It is not yet known which specific lower doses are being tested, since Novo Nordisk has not disclosed them ^[2].

What happens next

OASIS-5 began in August 2026 and is expected to conclude in 2028 ^[2]. Novo Nordisk has not released detailed public statements beyond an initial report from Reuters, cited in the coverage, so further specifics on dosing levels or timelines may emerge as the trial proceeds ^[2]. Until results are published, it is not known whether the lower doses will match the weight loss seen at higher approved doses, or how the FDA might view any future application based on this data.