What did @jofargus actually say?
@jofargus lost 32 kilograms in roughly 10.5 months on tirzepatide (Mounjaro) and noticed significant glute volume loss, what she calls "Ozempic butt." She acknowledges the rest of her body was also carrying excess weight before, and admits she "didn't really focus on building my glutes" during her weight loss phase. She says her gym trainer told her "it's not impossible to build muscle when you're in a calorie deficit, but it's really hard." She frames the muscle loss as an expected side effect of losing a significant amount of weight quickly and says she's at peace with it.
This is an honest, self-aware account. She isn't selling anything, isn't making medical claims, and she's threading together real experiences with some genuine nuance. That matters when we're evaluating what she got right and what she got incomplete.
Does the science back this up?
Mostly, yes. Rapid, large-magnitude weight loss does come with lean mass loss, and GLP-1 and GIP/GLP-1 drugs like tirzepatide don't exempt you from that. The trainer's comment about muscle gain in a deficit being hard is also generally accurate, though the framing skips some important nuance.
The SURMOUNT-1 trial (Jastreboff et al., 2022, New England Journal of Medicine), which studied tirzepatide in adults with obesity, found participants lost roughly 20-22% of body weight on the highest dose. Critically, a meaningful portion of that was lean mass, not just fat. Studies on semaglutide (STEP trials) have shown similar patterns. Heymsfield et al. (2021, Obesity Reviews) noted that without deliberate resistance training, roughly 25-39% of weight lost during caloric restriction can come from lean tissue. That's a big number. Losing 32 kg with a quarter or more of that from muscle is a real clinical concern, not just a cosmetic one.
On the deficit-and-muscle point: research by Barakat et al. (2020, Strength and Conditioning Journal) confirmed that muscle gain during a caloric deficit is possible, particularly in people with less training experience, but the rate is slower and protein intake becomes even more important.
What did they get wrong (or right)?
She got the broad strokes right. Muscle loss during aggressive caloric restriction is real and well-documented, and GLP-1-class drugs don't magically prevent it. Crediting her trainer for accurately flagging the difficulty of building muscle in a deficit is also fair.
Where the video falls short is in what it leaves out. The framing that "you're going to lose quite a lot of muscle mass" and "that's to be expected" could lead viewers to treat lean mass loss as inevitable and acceptable, rather than something that can be meaningfully reduced with the right strategy. Research consistently shows that higher protein intake, around 1.6-2.2 grams per kilogram of body weight (Morton et al., 2018, British Journal of Sports Medicine), combined with resistance training, substantially reduces the lean mass loss that comes with rapid weight loss.
She also conflates glute appearance with total muscle loss, which are related but not the same. Gluteal fat also contributes to shape, and its preferential loss during caloric restriction is a separate phenomenon from muscle atrophy. Both happen. Calling it "Ozempic butt" is catchy but blends two distinct physiological processes into one aesthetic complaint.
What should you actually know?
If you're on a GLP-1 or dual GIP/GLP-1 agonist and losing weight quickly, the most evidence-backed thing you can do to protect muscle is resistance training combined with adequate protein. This is not optional maintenance. It's an active intervention.
The clinical guidance from Apovian et al. (2015, Journal of Clinical Endocrinology and Metabolism) and more recent obesity medicine frameworks consistently recommend resistance exercise as part of any medically supervised weight loss program, partly because of the lean mass loss risk. A supervised program isn't about vanity. Losing skeletal muscle has downstream effects on metabolic rate, insulin sensitivity, and long-term weight maintenance. People who lose more lean mass during a weight loss phase tend to regain weight faster after stopping medication.
@jofargus says she focused on "getting stronger," which is genuinely good. Strength-focused training does help preserve muscle even when fat loss is the goal. Her outcome could have been different, or at least better, with more targeted glute-specific resistance work and possibly higher protein intake during the loss phase. That's not criticism. That's information most people on these medications aren't given upfront.
Is 'Ozempic butt' a real clinical phenomenon?
It's a real outcome described in anecdotal reports and consistent with known physiology, but "Ozempic butt" as a clinical term doesn't appear in peer-reviewed literature. What does appear is well-established: rapid caloric restriction causes loss of both adipose tissue and lean tissue, and the glutes are a large muscle group that can visibly change when both happen simultaneously.
The term has spread widely on social media as shorthand for this effect on GLP-1 drugs specifically, but the physiology is not unique to GLP-1 drugs. Anyone losing weight quickly without resistance training will experience something similar. The drugs are just enabling faster, larger weight loss than most people achieved before, which makes the lean mass loss more visible and rapid.