By Dr. Asnat Raziel, bariatric surgeon specializing in obesity treatment, metabolic health and healthy longevity; Director of the Multidisciplinary Center for Obesity Treatment, Assia Medical, Assuta Ramat HaChayal, Tel Aviv
The OASIS 4 trial is the study behind the Wegovy pill, the first oral form of semaglutide approved for weight management. In this article, I focus on the trial itself: who took part, how much weight they lost and how to read the numbers. In short, people on the pill lost an average of 13.6% of their body weight, compared with 2.2% on placebo.
Why the OASIS 4 trial matters
For years, effective drug treatment for obesity was linked mainly with a weekly injection. Now that is changing. The Wegovy pill delivers semaglutide as a daily tablet, with no needle at all.
The FDA, the US Food and Drug Administration, approved the pill in December 2025. This approval covers weight loss and keeping the weight off over time. In addition, it covers a lower risk of major cardiovascular events. In July 2026, the European Commission also approved the pill, at a dose of 25 mg once a day.
Who the Wegovy pill is for
Under the European approval, the pill is meant for adults with obesity, meaning a BMI of 30 or higher. It is also meant for adults with overweight (a BMI of 27 or higher) who have at least one weight-related condition. Treatment is always combined with a tailored diet and physical activity. If you are not sure whether it fits you, read my guide on who is a good candidate for the pill.
In Israel, the Wegovy pill arrived in November 2026 and can be obtained with Form 29G, a special Ministry of Health prescription form. Even earlier, in September 2026, a different pill reached Israel: Foundayo (orforglipron). For prices and practical details in Israel, see my article on getting started with the pill in Israel.
How the OASIS 4 trial was designed
The approval rests mainly on the OASIS 4 study, published in the New England Journal of Medicine (NEJM). It was a randomized, double-blind, placebo-controlled trial. It enrolled 307 adults without diabetes who had obesity, or overweight plus at least one related condition.
The researchers split the participants into two groups. In total, 205 people took oral semaglutide 25 mg once a day. By contrast, 102 took a placebo. Both groups also received lifestyle coaching at the same time.
OASIS 4 trial results: 13.6% average weight loss
After 64 weeks, participants on the pill had lost an average of 13.6% of their body weight. Placebo participants, however, lost only 2.2%. In other words, the difference was 11.4 percentage points.
In addition, the chances of losing 5%, 10%, 15% and even 20% of body weight were clearly higher with the pill. Physical function and quality of life improved as well. According to the company, people who stayed on treatment lost an average of 16.6%.
How to read the numbers from the OASIS 4 trial
Two figures appear in reports on the trial, and they answer different questions. The 13.6% figure includes everyone assigned to the pill, even those who stopped treatment or missed doses. So it reflects real life. The 16.6% figure, on the other hand, describes only those who stayed on treatment. It shows what the drug can do when taken as directed.
Also, the 11.4-point gap matters more than either number alone. That is because the placebo group also received lifestyle support. As a result, the gap shows the effect of the pill itself, beyond diet and exercise.
Side effects in the OASIS 4 trial
As with the injection, most side effects involved the digestive system. They occurred in 74.0% of patients on the pill, compared with 42.2% in the placebo group. These include nausea, diarrhea and constipation, which are well known from the injection.
In other words, switching to a pill does not remove the side effects of the GLP-1 drug family. That is why raising the dose gradually is so important. For a broader review, see my article on side effects of the Wegovy injection.
Is the pill as effective as the injection?
This is an important question. OASIS 4 did not compare the pill directly with the Wegovy 2.4 mg injection. Therefore, it cannot show on its own that the two treatments are equal.
However, an indirect comparison published in 2026 looked at OASIS 4 data alongside data from STEP 1. The researchers found similar efficacy on every weight-loss measure. The injection had a small numerical edge of about one percentage point, well below the level that matters clinically. Notably, most of the authors are employees of the manufacturer. For a fuller comparison, read my article on choosing between the daily pill and the weekly shot.
How is the Wegovy pill different from Rybelsus?
Both pills contain semaglutide. However, the Wegovy pill is not “Rybelsus under another name.” Rybelsus is approved for type 2 diabetes, at much lower doses. The new pill, by contrast, contains 25 mg and was designed from the start for long-term obesity treatment.
How to take the pill correctly
The way you take the pill directly affects how well it is absorbed. According to the manufacturer’s instructions, these are the rules:
- Take it in the morning, on an empty stomach.
- Use only a little water, up to about 120 ml.
- Swallow the pill whole, without splitting or chewing it.
- Wait half an hour before eating, drinking or taking other medicines.
Treatment starts at 1.5 mg. Your doctor then raises the dose gradually, about every 30 days, up to 25 mg. If you are thinking about moving from the injection, read about switching from the shot to the tablet.
Beyond the OASIS 4 trial: heart protection
The US approval also includes a lower risk of serious cardiovascular events: cardiovascular death, heart attack or stroke. This indication relies on the long experience with injectable semaglutide. For the injection, the data came from the large Wegovy heart study, which included people with heart disease and obesity. So for some patients, the decision is not only about weight but also about heart health.
Who the pill is less suitable for
The pill is not right for everyone. Like all drugs in this family, it must not be used by anyone with a personal or family history of medullary thyroid cancer. In addition, extra caution is needed after pancreatitis or with a digestive disease. Pregnancy, or planning a pregnancy, also means stopping treatment.
Finally, people who take many medicines in the morning should plan the order with their doctor. The reason is simple: the pill needs an empty stomach and half an hour without other medicines.
Why the Wegovy pill matters
The pill could greatly expand treatment options. Some people do not want to inject, are afraid of needles or simply prefer a pill. For them, a GLP-1 treatment without injections becomes accessible and practical.
On the other hand, a daily pill requires day-to-day consistency. It also requires careful timing and a short fast. So it will not necessarily be the right choice for every patient.
The bottom line
Obesity treatment keeps evolving quickly. Not long ago, we had very few options. Today, we can choose between different drugs and mechanisms, and even between a weekly injection and a daily pill. Ultimately, the OASIS 4 trial shows that the Wegovy pill offers an effective alternative for people who prefer not to inject. The right decision is made together with your doctor, based on your goals, health and lifestyle.
The information in this article is general and does not replace personal medical advice.
References
Oral Semaglutide at a Dose of 25 mg in Adults with Overweight or Obesity
Novo Nordisk A/S: Wegovy® pill approved in the US as first oral GLP-1 for weight management
No more injections? New weight-loss pill to launch in Israel next week
The studies were funded by Novo Nordisk, the drug’s manufacturer.
