Research

Mixed

Long-term pharmacotherapy for obesity (specifically fenfluramine-phentermine combination) produces modest net weight loss (2-10 kg) and improves the likelihood of losing >10% body weight, but weight loss plateaus by 6 months and significant regain occurs upon discontinuation.

Long-term medication can help you lose 2-10 kg and makes it more likely you'll lose over 10% of your body weight, but it is not a cure. You must combine it with diet and exercise. The weight loss plateaus after 6 months, and if you stop the medication, you will likely regain the weight. It is most useful for carefully selected patients who have comorbidities and have struggled with lifestyle changes alone.

ModerateQualifiesMEDIUM confidence
Net weight loss attributable to medication is modest, ranging from 2 to 10 kg, but patients taking active drug are more likely to lose 10% or more of initial body weight. Weight loss tends to reach a plateau by 6 months. Weight remains below baseline throughout treatment, although some studies show partial weight regain despite continued drug therapy.
JAMA · 1996

Why this rating

Based on a review of multiple studies, including one major long-term trial, but limited by short duration of many studies and lack of mortality data.

Source

Long-term Pharmacotherapy in the Management of Obesity

JAMA · 1996

DOI 10.1001/jama.1996.03540230057036

narrative_reviewCited 174×
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DOI resolved against Crossref · corpus check 2026-06-10

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