Oral Semaglutide (Obesity)Novo NordiskClinical Trials

The OASIS clinical trial program evaluated oral semaglutide at 50 mg for obesity treatment. OASIS 1 demonstrated 15.1% weight loss over 68 weeks in adults without diabetes, with 85% achieving at least 5% weight reduction. The FDA approved the 25 mg dose as the Wegovy pill on December 22, 2025.

Key Takeaways from OASIS Obesity Trials

Summary

EFFICACY
-15.1% body weight
vs placebo at 68 weeks (50 mg dose)
FDA STATUS
Approved (25 mg)
Wegovy pill, December 22, 2025
ELIGIBILITY
Adults with obesity
WITHOUT type 2 diabetes
SAFETY
GI side effects common
Mostly mild-moderate, manageable
OASIS Trial Program

Overview

The OASIS (Oral semaglutide treatment effect in people with obeSity) program is evaluating oral semaglutide for chronic weight management in adults with obesity or overweight. This is separate from the PIONEER diabetes program and tests higher doses (25 mg and 50 mg) specifically for weight loss in people without diabetes.[1]

The program includes OASIS 1 (50 mg dose in global population),[1] OASIS 2 (50 mg in East Asian population),[3] and OASIS 4 (25 mg dose, which forms the basis of the FDA application).[2] These trials are designed to determine whether oral semaglutide can achieve meaningful weight loss comparable to injectable obesity medications like Wegovy.

1OBESITY TREATMENT

Can oral semaglutide 50 mg achieve meaningful weight loss in adults with obesity without diabetes?

OASIS 1
68 weeks · Placebo-controlled · N=667
-15.1% body weight (50 mg dose) vs -2.4% placebo, with 85% achieving ≥5% weight loss—establishing oral semaglutide as an effective obesity treatment.
→ Jump to OASIS 1 details
2GEOGRAPHIC VARIATION

Does oral semaglutide work equally well in East Asian populations with different body composition?

OASIS 2
68 weeks · Japan & South Korea · N=TBD
East Asian-specific evaluation confirmed efficacy and safety in populations where metabolic disease occurs at lower BMI thresholds.
→ Jump to OASIS 2 details
Regulatory Timeline: OASIS 1 results were published in The Lancet in August 2023.[1] Novo Nordisk submitted an FDA application for the 25 mg dose on May 2, 2025, and the FDA approved it as the Wegovy pill on December 22, 2025.[2] Note: The 50 mg dose studied in OASIS 1 is not approved.
OASIS Program Timeline

Development History

After establishing oral semaglutide for diabetes (PIONEER program, 2016-2019), Novo Nordisk began investigating higher doses for obesity treatment. The OASIS trials launched in the early 2020s to evaluate whether oral semaglutide could match the weight loss efficacy of injectable formulations.

Important Note: This is investigational research on an unapproved dose (50 mg). For the current FDA review status and regulatory timeline, see our detailed overview.

OASIS 1: ORAL SEMAGLUTIDE 50 MG VS PLACEBO

Pivotal Obesity Trial

🔬OASIS 1
Phase 3Completed✗ Not Recruiting
Pivotal Obesity Treatment Trial
Enrollment 2021 – Results Published August 2023NCT05035095 →
KEY FINDINGS
  • -15.1% body weight reduction (50 mg) vs -2.4% (placebo) at 68 weeks
  • 85% achieved ≥5% weight loss (vs 26% placebo)
  • 69% achieved ≥10% weight loss (vs 12% placebo)
  • 54% achieved ≥15% weight loss (vs 6% placebo)
  • 34% achieved ≥20% weight loss (vs 3% placebo)
  • Weight loss comparable to injectable semaglutide (Wegovy)
CLINICAL SIGNIFICANCE

OASIS 1 demonstrated that an oral GLP-1 formulation can achieve weight loss efficacy comparable to injectable obesity medications. This represents a major advancement—offering patients an effective pill alternative to weekly injections for chronic weight management.

REGULATORY PATH

Results established proof of concept for oral obesity treatment. Novo Nordisk is seeking FDA approval for a 25 mg dose (OASIS 4), which may offer better tolerability while maintaining significant efficacy.

Adults with BMI ≥30 kg/m² OR BMI ≥27 kg/m² with weight-related complications, WITHOUT type 2 diabetes
Inclusion Criteria
  • Age 18+
  • Stable body weight (<5 kg change in prior 90 days)
  • Willing to follow lifestyle intervention
Key Exclusions
  • Type 1 or type 2 diabetes
  • HbA1c ≥6.5%
  • History of medullary thyroid cancer
  • Severe gastrointestinal disease
  • Recent bariatric surgery
Primary Endpoint:Body weight change at week 68: -15.1% (oral semaglutide) vs -2.4% (placebo); Achievement of ≥5% weight loss: 85% vs 26%at 68 weeks
Secondary Endpoints:
≥10% weight loss:69% vs 12%
≥15% weight loss:54% vs 6%
≥20% weight loss:34% vs 3%

OASIS 1 was a landmark trial demonstrating that oral semaglutide 50 mg achieves weight loss comparable to injectable GLP-1 medications like Wegovy (which typically achieves ~15% weight loss). The 12.7 percentage point difference versus placebo represents clinically meaningful weight reduction. With 85% of participants achieving at least 5% weight loss—the threshold for health benefits—this trial validated oral obesity treatment as a viable alternative to injections. The 50 mg dose, while effective, had higher GI side effects; the 25 mg dose under FDA review aims to balance efficacy and tolerability.

ClinicalTrials.gov: NCT05035095
OASIS 2: EAST ASIAN OBESITY STUDY

East Asian Population Trial

🔬OASIS 2
Phase 3Completed✗ Not Recruiting
East Asian Population Study
November 2021 – September 2023NCT05132088 →
KEY FINDINGS
  • Evaluated oral semaglutide 50 mg in Japan and South Korea
  • 68-week multicenter, double-blind, placebo-controlled trial
  • Confirmed efficacy in East Asian populations
  • Important for populations where metabolic disease occurs at lower BMI
CLINICAL SIGNIFICANCE

East Asian populations develop obesity-related metabolic complications at lower BMI thresholds compared to Western populations. This dedicated trial ensured that oral semaglutide is effective across diverse ethnic groups and addressed region-specific regulatory requirements.

REGULATORY PATH

Results support global approval efforts and inform dosing recommendations for East Asian markets where obesity is defined differently (BMI ≥25 kg/m² rather than ≥30 kg/m²).

Adults in Japan and South Korea with overweight or obesity, without type 2 diabetes
Inclusion Criteria
  • Age 18+
  • BMI ≥25 kg/m² (East Asian obesity threshold)
  • Weight-related complications if BMI 23-25 kg/m²
Key Exclusions
  • Type 1 or type 2 diabetes
  • History of medullary thyroid cancer
  • Severe gastrointestinal disease

OASIS 2 addressed a critical gap in obesity research: demonstrating efficacy in East Asian populations where body composition and metabolic disease risk differ from Western populations. By conducting a dedicated regional trial, Novo Nordisk ensured that oral semaglutide's weight loss benefits extend across ethnic groups and met regulatory requirements for Asian markets. This trial complements OASIS 1's global data with population-specific evidence.

ClinicalTrials.gov: NCT05132088
Adverse Events in OASIS Obesity Trials

Safety Profile

Important Context: Safety data below comes from the OASIS 1 trial (667 patients with obesity, 50 mg dose) and reflects adverse events in controlled research settings. The approved 25 mg dose (Wegovy pill) may have different tolerability. Real-world safety may vary.

Oral semaglutide 50 mg for obesity has a safety profile consistent with GLP-1 receptor agonists, with gastrointestinal side effects being most common.[1]

Gastrointestinal Adverse Events

In OASIS 1, GI side effects were notably higher with the 50 mg dose compared to the diabetes dose (14 mg):[1]

Adverse EventOral Semaglutide 50 mgPlacebo
Any GI Adverse Event80%46%
GI Events (Severity)Predominantly mild to moderate
Any Adverse Event (overall)92%86%

Most GI events were mild to moderate in severity.[1] They occurred predominantly during dose escalation and diminished over time. This transient pattern aligns with injectable GLP-1 experience.

Dose Considerations

The high GI adverse event rate with the 50 mg dose (80% experiencing GI side effects) prompted Novo Nordisk to evaluate a lower 25 mg dose in OASIS 4.

The 25 mg dose—which was the subject of the FDA application—may offer a better balance between weight loss efficacy and tolerability. The FDA approved the 25 mg dose as the Wegovy pill on December 22, 2025, making it the approved obesity dose.[2]

This dose optimization strategy reflects a common pattern in obesity medication development: starting with maximum efficacy studies (50 mg) and then refining to the optimal therapeutic dose (25 mg) that balances benefits and tolerability.

→ Complete safety profile and management strategies

How to Access Oral Semaglutide

Access

FDA Approval Status for Obesity

  • Current Status: APPROVED for obesity treatment at 25 mg (Wegovy pill)
  • Approved: 25 mg dose on December 22, 2025 (FDA application submitted May 2, 2025)[2]
  • Not approved: the 50 mg dose studied in OASIS 1
  • Note: Rybelsus (up to 14 mg) remains approved for type 2 diabetes (approved 2019)

Current Access

Important: For obesity, oral semaglutide is approved only as the 25 mg Wegovy pill. Rybelsus is approved for type 2 diabetes. The 50 mg dose studied in OASIS 1 is investigational and not available by prescription.

Approved on December 22, 2025, the 25 mg Wegovy pill became the first oral GLP-1 approved for weight loss. For more information about FDA review status and regulatory timeline, see our detailed overview.

Clinical Trial Participation

OASIS 1 and OASIS 2 trials are complete (enrollment closed). For information about ongoing obesity trials, visit ClinicalTrials.gov and search "oral semaglutide obesity."

ORAL SEMAGLUTIDE CLINICAL TRIAL QUESTIONS

FAQs

Oral semaglutide demonstrated similar A1C reduction to injectable liraglutide in the PIONEER 4 trial, with superior weight loss (-4.4 kg vs -3.1 kg, p = 0.0003).[3,14] In PIONEER 1, the 14 mg dose achieved -1.1% A1C reduction vs placebo, which is clinically meaningful and comparable to injectable GLP-1 efficacy.[1,12]

The SOUL trial (2025) showed 14% MACE reduction,[8] establishing cardiovascular benefits similar to injectable formulations. This places oral semaglutide on par with injectable GLP-1s for both glycemic control and cardiovascular protection.

For patients who prefer oral medications, oral semaglutide offers genuine equivalence to injectables without sacrificing efficacy.

Gastrointestinal effects are most common: nausea (15.4%-19.1%), diarrhea (10.1%-12.6%), and vomiting (6.6%-7.5%).[7] These are consistent with the GLP-1 class and typically mild to moderate in severity.

Most GI side effects occur during dose escalation and diminish over time.[7] Gradual titration (3 mg for 30 days, then 7 mg, then optional 14 mg) helps minimize these effects.

Overall adverse event rates were similar to placebo (56.6% vs 55.6%).[7] Discontinuation due to GI effects occurred in 11.6% of patients on the 14 mg dose,[7] meaning nearly 90% tolerated the medication well.

Yes. PIONEER 6 demonstrated cardiovascular safety (non-inferiority to placebo),[4] and the SOUL trial (2025) showed a 14% reduction in major adverse cardiovascular events (MACE) compared to placebo in high-risk patients.[8]

MACE includes cardiovascular death, non-fatal heart attack, and non-fatal stroke—the most serious cardiovascular complications. A 14% reduction represents meaningful protection.

This cardiovascular benefit is especially important since cardiovascular disease is the leading cause of death in people with diabetes. Oral semaglutide addresses both blood sugar control and cardiovascular risk.

A1C reductions are typically seen within 12 weeks, with full efficacy achieved by 26 weeks according to PIONEER trial data.[1]

The medication follows a dose escalation schedule: 3 mg for 30 days, then 7 mg (with optional increase to 14 mg after another 30 days). Peak glycemic control occurs after reaching the maintenance dose and continuing for several months.

Weight loss follows a similar timeline. Maximum weight reduction is typically seen by 52 weeks of treatment.

Yes. PIONEER 1 specifically evaluated oral semaglutide as monotherapy in treatment-naïve patients—those newly diagnosed or not currently on medication.[1]

The 14 mg dose achieved -1.1% A1C reduction vs placebo,[1] and 55%-77% of patients reached the ADA target of A1C less than 7%.[6] This makes oral semaglutide a viable first-line option for newly diagnosed type 2 diabetes.

Many patients start with metformin as first-line therapy, but oral semaglutide is an appropriate alternative when metformin is contraindicated or not tolerated. The cardiovascular benefits may make it particularly attractive for newly diagnosed patients with cardiovascular disease.

In head-to-head trials, oral semaglutide was superior to both sitagliptin (PIONEER 3)[2,13] and empagliflozin (PIONEER 2)[6] for A1C reduction. These are both commonly prescribed oral diabetes medications.

The added cardiovascular benefit (14% MACE reduction in SOUL)[8] further differentiates oral semaglutide from these agents, which have different cardiovascular profiles. SGLT-2 inhibitors like empagliflozin also show cardiovascular benefits, but through different mechanisms.

For patients seeking an oral medication with robust A1C reduction, weight loss, and cardiovascular protection, oral semaglutide represents a comprehensive option.

  1. Aroda VR, Rosenstock J, Terauchi Y, et al. "PIONEER 1: Randomized Clinical Trial of the Efficacy and Safety of Oral Semaglutide Monotherapy in Comparison With Placebo in Patients With Type 2 Diabetes." Diabetes Care. 2019. 42(9):1724-1732. https://pubmed.ncbi.nlm.nih.gov/31186300/
  2. Rosenstock J, Allison D, Birkenfeld AL, et al. "Effect of Additional Oral Semaglutide vs Sitagliptin on Glycated Hemoglobin in Adults With Type 2 Diabetes Uncontrolled With Metformin Alone or With Sulfonylurea: The PIONEER 3 Randomized Clinical Trial." JAMA. 2019. 321(15):1466-1480. https://pubmed.ncbi.nlm.nih.gov/30903796/
  3. Pratley R, Amod A, Hoff ST, et al. "Oral semaglutide versus subcutaneous liraglutide and placebo in type 2 diabetes (PIONEER 4): a randomised, double-blind, phase 3a trial." The Lancet. 2019. 394(10192):39-50. https://pubmed.ncbi.nlm.nih.gov/31186120/
  4. Husain M, Birkenfeld AL, Donsmark M, et al. "Oral Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes." New England Journal of Medicine. 2019. 381(9):841-851. https://www.nejm.org/doi/full/10.1056/NEJMoa1901118/
  5. Pieber TR, Bode B, Mertens A, et al. "Efficacy and safety of oral semaglutide with flexible dose adjustment versus sitagliptin in type 2 diabetes (PIONEER 7): a multicentre, open-label, randomised, phase 3a trial." The Lancet Diabetes & Endocrinology. 2019. 7(7):528-539. https://pubmed.ncbi.nlm.nih.gov/31189520/
  6. Thethi TK, Pratley R, Meier JJ. "Efficacy, safety and cardiovascular outcomes of once-daily oral semaglutide in patients with type 2 diabetes: The PIONEER programme." Diabetes, Obesity and Metabolism. 2020. 22(8):1263-1277. https://dom-pubs.onlinelibrary.wiley.com/doi/10.1111/dom.14054
  7. Aroda VR, Rosenstock J, Manghi FP, et al. "Safety and tolerability of semaglutide across the SUSTAIN and PIONEER phase IIIa clinical trial programmes." Diabetes, Obesity and Metabolism. 2023. 25(5):1385-1398. https://dom-pubs.onlinelibrary.wiley.com/doi/full/10.1111/dom.14990
  8. Knop FK, Aroda VR, Do NV, et al. "Oral Semaglutide and Cardiovascular Outcomes in High-Risk Type 2 Diabetes." New England Journal of Medicine. March 29, 2025. https://www.nejm.org/doi/full/10.1056/NEJMoa2501006
  9. Yamada Y, Katagiri H, Hamamoto Y, et al. "Dose-response, efficacy, and safety of oral semaglutide monotherapy in Japanese patients with type 2 diabetes (PIONEER 9): a 52-week, phase 2/3a, randomised, controlled trial." The Lancet Diabetes & Endocrinology. 2020. 8(5):377-391. https://www.thelancet.com/journals/landia/article/PIIS2213-8587(20)30075-9/fulltext
  10. Kaku K, Ueki K, Izumiya Y, et al. "Safety and efficacy of oral semaglutide versus dulaglutide in Japanese patients with type 2 diabetes (PIONEER 10): an open-label, randomised, active-controlled, phase 3a trial." The Lancet Diabetes & Endocrinology. 2020. 8(5):392-406. https://pubmed.ncbi.nlm.nih.gov/32333876/
  11. Lingvay I, Aizenberg D, Beckett D, et al. "Efficacy and safety of once-daily oral semaglutide 25 mg and 50 mg compared with 14 mg in adults with type 2 diabetes (PIONEER PLUS): a multicentre, randomised, phase 3b trial." The Lancet. 2023. 402(10403):693-704. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(23)01127-3/abstract
  12. "Efficacy and Safety of Oral Semaglutide Versus Placebo in Subjects With Type 2 Diabetes Mellitus (PIONEER 1)." ClinicalTrials.gov. https://clinicaltrials.gov/study/NCT02906930
  13. "Efficacy and Safety of Oral Semaglutide Versus Sitagliptin in Subjects With Type 2 Diabetes Mellitus (PIONEER 3)." ClinicalTrials.gov. https://clinicaltrials.gov/study/NCT02607865
  14. "Trial Comparing the Efficacy and Safety of Oral Semaglutide to Liraglutide and Placebo in Subjects With Type 2 Diabetes Mellitus (PIONEER 4)." ClinicalTrials.gov. https://clinicaltrials.gov/study/NCT02863419
  15. "A Trial Investigating the Cardiovascular Safety of Oral Semaglutide in Subjects With Type 2 Diabetes (PIONEER 6)." ClinicalTrials.gov. https://clinicaltrials.gov/study/NCT02692716
  16. "A Heart Disease Study of Semaglutide in Patients With Type 2 Diabetes (SOUL)." ClinicalTrials.gov. https://clinicaltrials.gov/study/NCT03914326
  17. "FDA approves Rybelsus (semaglutide), the first GLP-1 analog treatment available in a pill for adults with type 2 diabetes." Press Release. September 20, 2019. https://www.prnewswire.com/news-releases/fda-approves-rybelsus-semaglutide-the-first-glp-1-analog-treatment-available-in-a-pill-for-adults-with-type-2-diabetes-300922438.html
  18. "FDA approves Novo Nordisk's oral semaglutide for cardiovascular (CV) risk reduction in adults with type 2 diabetes who are at high risk." Press Release. 2025. https://www.prnewswire.com/news-releases/fda-approves-novo-nordisks-oral-semaglutide-for-cardiovascular-cv-risk-reduction-in-adults-with-type-2-diabetes-who-are-at-high-risk-including-those-who-have-not-had-a-prior-cv-event-302588005.html

Last updated October 6, 2026 · Key facts verified October 5, 2026

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