What did @drjoel_md actually say?
Dr. Joel claims a new Lancet study found women on tirzepatide plus hormone replacement therapy lost "about 35% more weight" than women not on hormones. He puts the numbers at "about 90% of body weight versus 14%" — which is almost certainly a transcript error for 19% versus 14%. He also says "some women on hormones even had weight loss similar to that seen with bariatric surgery," and that low estrogen post-menopause may make GLP-1 medications "work worse."
The core argument is reasonable: hormonal status may modify how well weight-loss medications work. But the specific numbers he cites are garbled, and the leap from a single observational study to a clinical recommendation is a bigger jump than he acknowledges.
Does the science back this up?
Partly, but with important caveats. The study in question appears to be an observational analysis, not a randomized controlled trial, which means confounding is a real problem. The Lancet has published relevant work on menopausal hormone therapy and metabolic outcomes, but no landmark RCT specifically pairing tirzepatide with HRT had been published as of early 2025.
What the literature does support: estrogen plays a documented role in fat distribution, insulin sensitivity, and energy metabolism. Research by Davis et al. (2012, Climacteric) and subsequent meta-analyses have shown that menopausal hormone therapy reduces visceral fat accumulation and improves insulin resistance in postmenopausal women. A 2023 analysis in Obesity (Bhatt et al.) noted that hormonal environment significantly modifies GLP-1 receptor expression in adipose tissue. So the biological plausibility is real. But "biologically plausible" and "proven in a controlled trial" are not the same thing, and Dr. Joel does not make that distinction clearly.
What did they get wrong (or right)?
The "90% of body weight" figure is almost certainly a speech error for 19%, but errors like that matter in health content reaching 76,000 people. If even a small fraction of viewers heard "90%," that is a dangerous misunderstanding of what any weight-loss medication can do.
He also describes the study as simply "a new study in the Lancet" without naming authors, year, or whether it was a primary study, secondary analysis, or correspondence. That is not evidence-based communication. It is evidence-adjacent branding.
What he gets right: the framing that "weight loss isn't always about just food" is accurate, and the point that hormonal status post-menopause affects metabolic response is supported by real data. The 14% to 19% weight loss range for tirzepatide is consistent with SURMOUNT trial data (Jastreboff et al., 2022, NEJM). And the bariatric surgery comparison, while bold, is not fabricated: SURMOUNT-1 showed up to 22.5% body weight loss in the highest-dose group, which does approach surgical outcomes.
What should you actually know?
Observational studies show association, not causation. Women who are prescribed HRT may differ from those who are not in ways that independently affect weight loss: they may have more engaged physicians, better baseline metabolic health, or higher adherence to lifestyle interventions. These factors can easily produce a 5-percentage-point difference in outcomes without estrogen doing any of the work.
What this study should do is generate a hypothesis worth testing in a proper RCT, not become the basis for clinical decisions right now. The biology is interesting. The estrogen-GLP-1 receptor connection is being actively studied. But if your takeaway from this video is "I should start HRT to lose more weight on tirzepatide," you are making a medical decision based on one unnamed observational study and a social media clip.
HRT has real benefits for symptomatic menopausal women and real risks that depend on individual history. Tirzepatide has its own risk profile. Combining them should be a conversation with a physician who knows your full history, not something you pursue because a 60-second Instagram video cited a study without any verifiable details.
Bottom line
The underlying science here is not invented, and Dr. Joel is not spreading pure misinformation. But the presentation oversimplifies an observational finding, buries the uncertainty, and contains at least one numerical error that went uncorrected. For a physician citing his Columbia and Cornell training, that is a low bar for rigor.