Question 1

What did STEP-2 actually find?

Accepted Answer

On its primary endpoint — How much body weight came off over 68 weeks, on the 2.4 mg dose against placebo — the treatment arm recorded −9.6% against −3.4% for the comparator. Estimated treatment difference −6.2 percentage points (95% CI −7.3 to −5.2; P<0.0001). There was a second half to the endpoint: 68.8% on the 2.4 mg dose shed 5% of body weight or more, where 28.5% on placebo did. Set the headline figure next to STEP-1's 14.9%: the same drug, dose and trial length produced five percentage points less, and diabetes is the difference.

Question 2

How large was STEP-2, and how long did it run?

Accepted Answer

1,210 participants, over 68 weeks on treatment, the first 16 spent stepping the dose up, then 7 weeks off the drug to week 75. It was a Phase 3 trial, finished; published March 2021. Registered as NCT03552757, which you can look up yourself rather than taking anyone's summary for it.

Question 3

Who was studied in STEP-2?

Accepted Answer

Adults 18 and over carrying a BMI of 27 or higher, whose type 2 diabetes had been diagnosed at least 180 days before, running an HbA1c of 7.0% to 10.0%, and managed either by diet and exercise alone or by up to three stable oral drugs (metformin, a sulfonylurea, an SGLT2 inhibitor, a glitazone). Anyone on insulin was excluded. Average starting weight 99.8 kg at a BMI of 35.7, average HbA1c 8.1%, average age 55, half women, 62.1% white, and about eight years since diagnosis. Run at 149 sites in 12 countries from June 2018 to March 2020. ⚠ A trial result describes the population it was measured in. If you differ from it materially — in age, in baseline weight, in whether you have diabetes — the number is context rather than a prediction.

Question 4

What side effects were reported in STEP-2?

Accepted Answer

The most commonly reported were nausea (33.5% (sema 2.4 mg) against 9.2% (placebo) on comparator), diarrhea (21.3% (sema 2.4 mg) against 11.9% (placebo) on comparator), vomiting (21.3% (sema 2.4 mg) against 2.7% (placebo) on comparator). The leading complaint, usually mild to moderate and bunched into the weeks when the dose was rising. The 1.0 mg dose produced it in 31.8%. The nausea, diarrhea, vomiting, constipation and indigestion rates are the nonserious events counted from week 0 to week 75, per the trial's ClinicalTrials.gov results. Rates come from this trial's population under its own dose-escalation schedule; a faster or slower titration changes what people experience.

Question 5

What else did STEP-2 measure?

Accepted Answer

Secondary endpoints included the weight dose against the diabetes dose, head to head (−9.6% (2.4 mg) against −7.0% (1.0 mg)); lost at least 5% of body weight (68.8% (2.4 mg); 57.1% (1.0 mg) against 28.5% (placebo)); lost at least a tenth of body weight (45.6% (2.4 mg); 28.7% (1.0 mg) against 8.2% (placebo)). ⚠ Secondary endpoints are weaker evidence than the primary one — a trial is powered for its primary outcome, and the rest are read as supporting rather than as findings in their own right.

Question 6

Does STEP-2 apply to compounded semaglutide?

Accepted Answer

No, and this matters because the number gets used that way. STEP-2 tested Semaglutide 2.4 mg (Wegovy) — the FDA-approved product, made by its manufacturer under Good Manufacturing Practice, at the doses and schedule the protocol specified. A compounded preparation of semaglutide is a different product: no agency has reviewed that specific preparation for safety, effectiveness or manufacturing quality, and its concentration is set by whichever pharmacy filled it. ⛔ A seller quoting this trial's result beside a compounded price is quoting evidence that was generated on something they are not selling. That is not the same as saying compounded semaglutide does not work — it is saying nobody measured it here.

Question 7

Does STEP-2 mean this drug will work for me?

Accepted Answer

It cannot tell you that. A trial reports an average across a defined population under a fixed protocol, with monitoring and adherence support most people do not get. It is the best evidence available and it is still a distribution rather than a promise — some participants lost far more than the mean and some lost nothing. What it is genuinely good for is comparing options against each other, which is what the rest of this section is for.

Endpoint	Treatment	Comparator	Difference
The weight dose against the diabetes dose, head to head The most useful comparison in practice, because it is Wegovy's dose against Ozempic's in the same trial and the same patients. The higher dose bought about 2.7 more percentage points of weight.	−9.6% (2.4 mg)	−7.0% (1.0 mg)	Estimated treatment difference −2.7 percentage points (95% CI −3.7 to −1.6; P<0.0001)
Lost at least 5% of body weight Roughly seven in ten on the weight dose, closer to six in ten on the diabetes dose, and under three in ten on placebo.	68.8% (2.4 mg); 57.1% (1.0 mg)	28.5% (placebo)	Odds ratio 4.88 (95% CI 3.58 to 6.64) for 2.4 mg vs placebo; P<0.0001
Lost at least a tenth of body weight Five and a half times the placebo rate, in a population where older weight drugs barely separated from placebo at all.	45.6% (2.4 mg); 28.7% (1.0 mg)	8.2% (placebo)	Odds ratio 7.41 (95% CI 4.95 to 11.08) for 2.4 mg vs placebo; P<0.0001
Lost at least 15% About a quarter got here, against half the participants in the non-diabetic trial. If 15% is your target, diabetes makes it materially less likely.	25.8% (2.4 mg); 13.7% (1.0 mg)	3.2% (placebo)	Odds ratio 7.65 (95% CI 4.44 to 13.20) for 2.4 mg vs placebo; P<0.0001
Three-month average blood sugar The two doses were indistinguishable on blood sugar (1.6 against 1.5 points). That answers much of the dose question below: blood sugar tops out around the lower dose while weight keeps responding to more.	−1.6 (2.4 mg); −1.5 (1.0 mg)	−0.4 (placebo)	Estimated treatment difference −1.2 percentage points (95% CI −1.4 to −1.1) for 2.4 mg vs placebo; P<0.0001
Inches off the waist About 9 cm, roughly 3.5 inches, against 4.5 cm on placebo.	−9.4 cm (2.4 mg)	−4.5 cm (placebo)	Estimated treatment difference −4.9 cm (95% CI −6.0 to −3.8); P<0.0001
Top blood-pressure number Down about 3.4 points beyond placebo, smaller than the drop in the non-diabetic trial, in line with the smaller weight change.	−3.9 mmHg (2.4 mg)	−0.5 mmHg (placebo)	Estimated treatment difference −3.4 mmHg (95% CI −5.6 to −1.3); P=0.0016
Blood sugar after an overnight fast A drop of roughly 37 mg/dL beyond placebo. Unlike the non-diabetic trials, this is treatment of something rather than movement inside the normal range.	−38.0 mg/dL (2.4 mg)	−1.4 mg/dL (placebo)	Estimated treatment difference −36.6 mg/dL
How people rated their own physical functioning, on a weight-specific questionnaire Physical functioning improved in both arms, by 4.8 points more on the drug.	+10.1 points (2.4 mg)	+5.3 points (placebo)	Estimated treatment difference 4.8 points (95% CI 1.8 to 7.9); P=0.0018
Triglycerides, a blood fat Down about 22% against 9% on placebo.	0.78 (2.4 mg; 22% relative reduction)	0.91 (placebo; 9% relative reduction)	Estimated treatment ratio 0.86 (95% CI 0.81 to 0.92)

Event	Treatment rate	Comparator rate
Nausea The leading complaint, usually mild to moderate and bunched into the weeks when the dose was rising. The 1.0 mg dose produced it in 31.8%. The nausea, diarrhea, vomiting, constipation and indigestion rates are the nonserious events counted from week 0 to week 75, per the trial's ClinicalTrials.gov results.	33.5% (sema 2.4 mg)	9.2% (placebo)
Diarrhea Similar at both doses: 21.9% at 1.0 mg.	21.3% (sema 2.4 mg)	11.9% (placebo)
Vomiting This one does scale with dose (13.4% at 1.0 mg against 21.3% at 2.4 mg) and is part of what the extra weight loss costs.	21.3% (sema 2.4 mg)	2.7% (placebo)
Constipation Roughly three times the placebo rate.	17.4% (sema 2.4 mg)	5.5% (placebo)
Indigestion Five times the placebo rate, though uncommon in absolute terms.	6.2% (sema 2.4 mg)	1.2% (placebo)
Confirmed low blood sugar with symptoms This matters if you have diabetes, and it does not appear in the non-diabetic trials at all. Severe episodes were rare either way, and the excess sat almost entirely in people also taking a sulfonylurea, a known combination risk. If you are on one, raise it with your prescriber before starting.	5.7% (sema 2.4 mg)	3.0% (placebo)
Diabetic eye disease Slightly higher than placebo without reaching significance. It echoes the signal seen in other semaglutide diabetes trials, where rapidly dropping blood sugar appears to be the trigger rather than the drug itself. Existing retinopathy is a reason for an eye check before starting. Source: the FDA's clinical review.	4.0% (sema 2.4 mg)	2.7% (placebo)
Gallbladder problems Uncommon here and close to placebo (about 1% or less in every arm, per the FDA's clinical review), unlike the trials in people without diabetes. Losing weight quickly raises gallstone risk regardless of the method.	1.0% (sema 2.4 mg)	0.7% (placebo)
Stopped the drug over a side effect 6.2% at the weight dose against 5.0% at the diabetes dose and 3.5% on placebo, about two-thirds of it stomach and bowel trouble. Source: the FDA's clinical review.	6.2% (sema 2.4 mg)	3.5% (placebo)
Serious adverse events of any kind Close to the placebo rate, per the trial's ClinicalTrials.gov results.	9.9% (sema 2.4 mg)	9.2% (placebo)

STEP-2: Semaglutide With Type 2 Diabetes

Primary endpoint

Secondary endpoints

Adverse events

Clinical significance

Who sells semaglutide, and for how much

Frequently Asked Questions

References