The STEP (Semaglutide Treatment Effect in People with obesity) program established semaglutide 2.4 mg as a chronic weight management therapy. The trials cover the foundational efficacy (STEP-1), maintenance (STEP-4), and disease-specific extensions (STEP-HFpEF, STEP-Kidney).

STEP-1 — the foundational trial

STEP-1 (Wilding et al., NEJM 2021) randomized 1,961 adults with BMI ≥30 (or ≥27 with weight-related comorbidity), without diabetes, to semaglutide 2.4 mg weekly or placebo, plus lifestyle intervention.

Mean weight loss at 68 weeks: 14.9% (semaglutide) vs 2.4% (placebo).
32% of semaglutide patients lost ≥20% of body weight.
Cardiometabolic risk factors (waist circumference, lipids, A1c, blood pressure) improved meaningfully.
The trial established Wegovy's path to FDA approval (June 2021).

STEP-4 — what happens when you stop

STEP-4 (Rubino et al., JAMA 2021) tested what happens when semaglutide is discontinued after 20 weeks of escalation. Participants who continued kept the weight off; those who switched to placebo regained much of it.

Continuation arm: additional weight loss to total ~17%.
Withdrawal arm: ~7% regain.
This is why obesity is now framed as a chronic disease requiring long-term therapy — the same way hypertension and T2D are.

STEP-HFpEF — semaglutide in heart failure with preserved ejection fraction

Kosiborod et al. (NEJM 2023) randomized 529 adults with HFpEF + obesity to semaglutide 2.4 mg or placebo.

Improved KCCQ-CSS symptom score by 7.8 points more than placebo at 52 weeks.
Improved 6-minute walk distance.
Reduced NT-proBNP and CRP.
Suggests benefit beyond weight loss — direct cardiac effects.

STEP-1 follow-up extension

Long-term extension data through 4–5 years have begun reporting. Weight loss is largely maintained with continued therapy; discontinuation produces the predicted regain. This reinforces the chronic-disease therapeutic model.

Implications for current practice

14–17% weight loss is a realistic expectation at full dose with good adherence.
Long-term therapy is the default expectation; discontinuation produces regain.
Cardiometabolic benefits accompany weight loss even without dedicated cardiometabolic indication.

See our research bibliography for full citations with DOIs.