Phase 3 · Semaglutide

OASIS 1 trial results

Efficacy and Safety of Oral Semaglutide 50 mg Once Daily in Subjects With Overweight or Obesity (OASIS 1)

Percentage Change in Body Weight (Percentage (%) change in body weight), Baseline (week 0), end-of-treatment (week 68). Oral Semaglutide 50 mg: -15.8; Placebo: -2.2.

Participants: 667
Status: completed
Completed: 2023-05-12
Sponsor: Novo Nordisk A/S

As posted on ClinicalTrials.gov (NCT05035095), updated at source May 7, 2026. Read again whenever the registry updates it. Registry figures can differ from a published paper, which may use another analysis.

Primary outcome

What OASIS 1 measured first

Percentage Change in Body WeightPercentage (%) change in body weight · Baseline (week 0), end-of-treatment (week 68) · mean

Oral Semaglutide 50 mgn=317	Placebon=295
-15.8(10.3)	-2.2(7.2)

Number of Participants Who Achieved Weight Loss Greater Than or Equal (≥) 5% (Yes/No)Participants · At end-of-treatment (week 68) · count of participants

Measure	Oral Semaglutide 50 mgn=317	Placebon=295
Yes	269	76
No	48	219

Side effects by arm

Side effects in OASIS 1

Percent of participants affected, From baseline (week 0) to end-of-study (week 75). The most common events the registry lists.

Event	Oral Semaglutide 50 mg	Placebo
Any serious event	9.6%	8.7%
Nausea	51.8%	15.3%
COVID-19	35.6%	34.5%
Constipation	27.5%	15%
Diarrhoea	26.6%	16.8%
Vomiting	24%	3.6%
Decreased appetite	16.8%	7.2%
Nasopharyngitis	11.4%	14.7%
Dyspepsia	14.1%	5.1%
Headache	13.8%	8.7%
Arthralgia	6.6%	11.4%
Eructation	9.6%	2.1%
Abdominal pain upper	9.3%	3.6%
Gastrooesophageal reflux disease	8.7%	3.3%
Dizziness	8.1%	4.5%
Influenza	7.8%	5.4%
Abdominal distension	7.5%	4.8%
Back pain	4.8%	7.2%
Fatigue	7.2%	6%
Alopecia	6.9%	2.7%
Abdominal pain	6.6%	4.8%
Hypertension	3%	6.6%
Upper respiratory tract infection	5.7%	6%
Flatulence	5.7%	3.9%
Urinary tract infection	5.7%	1.8%
Gastroenteritis	5.4%	3%

Secondary outcomes

What else it measured

Number of Participants Who Achieved Weight Loss Greater Than or Equal (≥) 10% (Yes/No)Participants · At end-of-treatment (week 68) · count of participants

Measure	Oral Semaglutide 50 mgn=317	Placebon=295
Yes	220	35
No	97	260

Number of Participants Who Achieved Weight Loss Greater Than or Equal (≥) 15% (Yes/No)Participants · At end-of-treatment (week 68) · count of participants

Measure	Oral Semaglutide 50 mgn=317	Placebon=295
Yes	170	17
No	147	278

Number of Participants Who Achieved Weight Loss Greater Than or Equal (≥) 20% (Yes/No)Participants · At end-of-treatment (week 68) · count of participants

Measure	Oral Semaglutide 50 mgn=317	Placebon=295
Yes	107	8
No	210	287

Change in Waist Circumferencecentimeter (cm) · Baseline (week 0), end-of-treatment (week 68) · mean

Oral Semaglutide 50 mgn=317	Placebon=295
-13.4(10.0)	-2.8(7.3)

Change in Body Mass Index (BMI)Kilogram per meter square (kg/m^2) · Baseline (week 0), end-of-treatment (week 68) · mean

Oral Semaglutide 50 mgn=317	Placebon=295
-5.9(4.0)	-0.9(2.8)

Change in Impact of Weight on Quality of Life-Lite-Clinical Trials Version (IWQOL-Lite-CT) Physical FunctionScore on a scale · Baseline (week 0), end-of-treatment (week 68) · mean

Oral Semaglutide 50 mgn=298	Placebon=278
14.5(20.2)	5.0(19.9)

Change in Short Form 36 v2.0 Acute (SF-36) Physical Functioning DomainScore on a scale · Baseline (week 0), end-of-treatment (week 68) · mean

Oral Semaglutide 50 mgn=303	Placebon=280
2.4(5.7)	-0.0(5.4)

Change in Systolic Blood PressureMillimeter of mercury (mmHg) · Baseline (week 0), end-of-treatment (week 68) · mean

Oral Semaglutide 50 mgn=317	Placebon=295
-7(14)	-1(14)

Change in Diastolic Blood PressureMillimeter of mercury (mmHg) · Baseline (week 0), end-of-treatment (week 68) · mean

Oral Semaglutide 50 mgn=317	Placebon=295
-2(9)	-1(10)

Change in Glycosylated Haemoglobin (HbA1c)Percentage of HbA1c · Baseline (week 0), end-of-treatment (week 68) · mean

Oral Semaglutide 50 mgn=311	Placebon=286
-0.2(0.3)	0.1(0.3)

Change in Fasting Plasma Glucose (FPG)Milligrams per deciliter (mg/dL) · Baseline (week 0), end-of-treatment (week 68) · mean

Oral Semaglutide 50 mgn=313	Placebon=292
-10.3(12.7)	-1.8(10.4)

Change in Fasting Serum Insulin (Pmol/L) - Ratio to BaselineRatio of fasting serum insulin · Baseline (week 0), end-of-treatment (week 68) · geometric mean

Oral Semaglutide 50 mgn=275	Placebon=260
0.67(71.4)	0.94(55.3)

The trial

How OASIS 1 was run

This study is being conducted to see if semaglutide tablets can be used as a treatment to help people living with overweight or obesity lose weight. This study will look at the change in participants body weight. Participants will either get semaglutide tablets (new medicine) or placebo tablets ('dummy' medicine that looks like semaglutide but has no effect on the body). For a fair comparison, people are divided into two groups at random by a computer. This process is called randomisation. Semaglutide tablets are new medicine being tested to treat overweight and obesity. Doctors in many countries can already prescribe semaglutide tablets at lower doses to treat type 2 diabetes. Participants will get semaglutide or placebo tablets for 68 weeks and will need to take 1 tablet every morning In addition to taking the medicine, participants will have talks with study staff about: * healthy food choices * how to be more physically active * what participants can do to lose weight The study will last for about 1½ year.Participants will have 14 clinic visits and 7 phone calls with the study doctor. Blood samples will be taken at 10 visits. Participants will have a test to check their heart done at 3 visits. Women cannot take part if pregnant, breast-feeding or plan to get pregnant during the study period. If participant is a woman and is able to become pregnant, participant will be checked for pregnancy via urine tests.

Oral semaglutide: Participants will receive once daily semaglutide tables in a dose escalating manner for 68 weeks: 3 mg (week 1-4), 7 mg (week 5-8), 14 mg (week 9-12), 25 mg (week 13-16) and 50 mg (week 17-68)
Oral semaglutide placebo: All participants are given once daily dose for 68 weeks

Who could join the trial

Inclusion Criteria: * Male or female, age greater than or equal to 18 years at the time of signing informed consent * Body mass index (BMI): greater than or equal to 27.0 kg/m\^2 with the presence of at least one of the following weight-related complications (treated or untreated): hypertension, dyslipidaemia, obstructive sleep apnoea or cardiovascular disease OR greater than or equal to 30.0 kg/m\^2 * History of at least one self-reported unsuccessful dietary effort to lose body weight Exclusion Criteria: * HbA1c greater than or equal to 6.5% (48 mmol/mol) as measured by the central laboratory at screening * A self-reported change in body weight greater than 5 kg (11 lbs) within 90 days before screening irrespective of medical records

Published papers

Papers from OASIS 1

Knop FK, Aroda VR, do Vale RD, Holst-Hansen T, Laursen PN, Rosenstock J, Rubino DM, Garvey WT; OASIS 1 Investigators. Oral semaglutide 50 mg taken once per day in adults with overweight or obesity (OASIS 1): a randomised, double-blind, placebo-controlled, phase 3 trial. Lancet. 2023 Aug 26;402(10403):705-719. doi: 10.1016/S0140-6736(23)01185-6. Epub 2023 Jun 26.

Trial averages do not predict what one person will experience. Results are shown as the registry posts them, without interpretation.

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