There is no prescription drug that produces major, lasting weight loss
The old claim turned out to be wrong and was rejected by evidence.
TaughtWeight is a matter of diet and willpower. The few prescription diet drugs that exist are marginally effective and often dangerous; the history of obesity medicine is a graveyard of withdrawn pills. Nothing on prescription reliably produces large, sustained weight loss.
NowOn 4 June 2021, the FDA approved Wegovy (semaglutide 2.4 mg), a once-weekly injection that produced an average weight loss of roughly 15–17% over 68 weeks in trials: results previously seen only with bariatric surgery, and far beyond any earlier weight-loss drug.
What actually happened
Semaglutide is a GLP-1 receptor agonist, mimicking a gut hormone that regulates appetite and fullness; it was already used for diabetes before its effect on weight was pursued in its own right. The scale of the effect is what broke the old teaching; it moved obesity drugs from 'a few percent, with caveats' into surgery-adjacent territory.
The honest limits: it is an ongoing treatment, weight tends to return if you stop, it has side effects, and cost and supply have been real barriers. And it reframed rather than erased the role of diet. But the flat claim (that no prescription drug delivers major, durable weight loss) no longer holds, and a wave of even stronger drugs followed.
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Who was taught this
Still standard through 2021, so anyone who finished school between 1950 and 2021 learned the earlier version.