A third of the weight vanishes from muscle, not fat.
À medida que milhões de pessoas recorrem aos medicamentos GLP-1 para perder peso, a ciência começa a confrontar uma consequência silenciosa: junto com a gordura, vai embora também o músculo. Um novo fármaco chamado apitegromabe surge como possível resposta a esse dilema, prometendo preservar a massa magra sem comprometer a perda de gordura. O episódio revela algo mais amplo sobre a relação humana com o corpo — a busca pela transformação rápida e os custos invisíveis que ela pode cobrar.
- Cerca de um terço do peso perdido com medicamentos como Ozempic e Mounjaro vem da massa muscular, causando mudanças visíveis no corpo que pacientes e cirurgiões plásticos já batizaram de 'bumbum Ozempic'.
- Um ensaio clínico com 102 adultos mostrou que o apitegromabe, usado junto ao Mounjaro, reduziu a perda muscular de 30% para menos de 15% do peso total eliminado — preservando quase 2 quilos a mais de massa magra.
- O medicamento ainda exige administração intravenosa e está restrito a estudos clínicos, enquanto pesquisadores alertam que os resultados iniciais, embora promissores, ainda não provam benefícios concretos para força ou qualidade de vida.
- Especialistas lembram que a velocidade da perda de peso — e não o remédio em si — é a raiz do problema, e que nutrição adequada e exercícios de força continuam sendo recomendações fundamentais para quem usa GLP-1.
- O apitegromabe aponta para uma nova fronteira: intervir farmacologicamente na composição corporal, indo além da pergunta 'quanto se perde' para questionar 'o que exatamente se está perdendo'.
Quando alguém começa a tomar Ozempic ou Mounjaro para emagrecer, a balança costuma trazer boas notícias — mas o corpo conta uma história mais complexa. Um terço do peso que desaparece não é gordura: é músculo. O resultado visível ficou conhecido como 'bumbum Ozempic', um afrouxamento e achatamento de regiões do corpo que perderam tecido muscular. Cirurgiões plásticos nos Estados Unidos relatam aumento nas consultas por essa razão específica.
Um estudo publicado na revista Nature Medicine trouxe uma possível resposta: o apitegromabe, um medicamento que bloqueia uma proteína envolvida na degradação muscular. No ensaio, 102 adultos usaram o fármaco ou placebo junto ao Mounjaro por seis meses. O grupo que recebeu o apitegromabe preservou cerca de 1,9 quilo a mais de massa magra — 55% mais tecido muscular — enquanto a perda de gordura seguiu no ritmo esperado. No grupo placebo, 30% do peso perdido era músculo; no grupo tratado, esse número caiu para 14,6%.
Ainda assim, especialistas pedem cautela. A pesquisadora Marie Spreckley descreveu os resultados como 'evidências iniciais encorajadoras', não como prova de benefício clínico real. Estudos mais longos são necessários para saber se preservar músculo se traduz em mais força e melhor qualidade de vida. Brendan Gabriel, da Universidade de Aberdeen, sugeriu que o tratamento pode não ser adequado para todos, mas poderia ajudar quem perde massa muscular de forma especialmente acelerada.
O problema de fundo não está nos medicamentos em si, mas na velocidade da perda de peso que eles proporcionam. Quando o emagrecimento é rápido, o corpo tem dificuldade de preservar o músculo — e, ao contrário da gordura, o músculo perdido é difícil de recuperar. As recomendações atuais já incluem exercícios de força e ingestão adequada de proteína. O apitegromabe propõe um caminho adicional: uma intervenção farmacológica que atue diretamente na composição corporal, deslocando a pergunta de 'quanto se perde' para 'o que exatamente está sendo perdido'.
When people start taking GLP-1 medications like Ozempic or Mounjaro to lose weight, something unexpected often happens. The scale moves in the right direction, but the body changes in ways that weren't part of the plan. A third of the weight that disappears comes not from fat, but from muscle. The result is what some have begun calling "Ozempic butt"—a flattening and sagging of the buttocks and other areas as the body sheds tissue it needs. Plastic surgeons in the United States have reported a noticeable uptick in consultations about this specific concern.
Now a new medication called apitegromab offers a potential solution. In a study published in Nature Medicine, researchers found that when patients took this drug alongside obesity treatment, they preserved significantly more muscle while still losing fat at the expected rate. The trial involved 102 adults, mostly women, who received either apitegromab or a placebo in combination with Mounjaro over six months. Those who got the new drug retained roughly 1.9 kilograms more muscle mass—about 55 percent more lean tissue overall. In the placebo group, muscle loss accounted for 30.2 percent of total weight shed. In the apitegromab group, that figure dropped to 14.6 percent.
The mechanism is straightforward in concept. Apitegromab works by blocking a protein involved in muscle breakdown. The drug is currently available only in clinical trials and must be administered intravenously. The company developing it is exploring whether it could eventually be delivered via a self-injecting pen, similar to the devices patients already use for GLP-1 medications themselves. The same drug is also being studied for other muscle-wasting conditions, including spinal muscular atrophy.
But experts urge caution about reading too much into these early results. Marie Spreckley, a researcher not involved in the study, called the findings "encouraging initial evidence" rather than proof of real clinical benefit. She and others emphasize that longer studies are needed to determine whether preserving muscle actually translates to better strength, quality of life, and health outcomes over time. Brendan Gabriel, a specialist in health and nutrition at the University of Aberdeen, suggested the treatment might not be right for everyone using GLP-1 drugs, but could help those experiencing particularly rapid muscle loss.
The underlying problem stems not from the medications themselves but from the speed of weight loss they enable. GLP-1 drugs suppress appetite and extend feelings of fullness, causing people to eat significantly less. When weight drops quickly, the body struggles to preserve muscle tissue. Unlike fat, muscle is difficult to rebuild once lost. Current guidance already recommends that people using these medications maintain good nutrition and exercise regularly, including strength training. The British health service suggests at least two sessions per week of muscle-building activity—anything from weight lifting to gardening, stair climbing, or dancing. Protein intake matters too; research indicates that consuming 20 to 40 grams of protein per meal helps maintain or build muscle.
Apitegromab represents a different approach: a pharmaceutical intervention to prevent the loss rather than relying solely on behavior change. It's worth noting that GLP-1 medications were never designed for short-term weight loss or cosmetic purposes, yet many people use them exactly that way, chasing what they call a "summer body." Health experts discourage this off-label use, though they acknowledge it happens frequently. The question now is whether apitegromab, if it proves safe and effective in larger trials, might become part of a more complete treatment strategy—one that addresses not just how much weight someone loses, but what kind of weight it is.
Citas Notables
The results are encouraging initial evidence, but should not be seen as definitive proof of clinical benefit.— Marie Spreckley, researcher
The treatment may not be appropriate for all GLP-1 users, but could benefit those experiencing accelerated muscle loss.— Brendan Gabriel, University of Aberdeen
La Conversación del Hearth Otra perspectiva de la historia
Why does the body shed muscle so aggressively when someone loses weight quickly on these drugs?
It's not the drug itself—it's the speed. When you eat far less, your body needs energy, and muscle is metabolically expensive to maintain. It breaks it down for fuel. Fat is easier to preserve because it's less costly. The drugs work by killing appetite, so the weight loss happens faster than the body can adapt.
And muscle is harder to get back than fat?
Much harder. You can gain fat passively. Muscle requires consistent stimulus—lifting, resistance, protein. It takes weeks or months to rebuild what's lost in weeks.
So this new drug, apitegromab—it's not helping people lose more weight. It's protecting what they already have.
Exactly. It blocks a protein that tells muscles to break down. The fat loss stays the same. The muscle stays put. It's a different problem than the drug solves.
The study was only six months. Why do experts want longer trials?
Because nobody knows yet if keeping the muscle actually matters for health. Does it improve strength? Energy? Does it prevent the frailty that sometimes comes with rapid weight loss? Those answers take time.
And it still has to go through a vein right now.
Yes. They're working on a pen version, like the GLP-1 drugs themselves. But that's not here yet. It's still experimental.
Who would actually need this? Everyone losing weight on these drugs?
Probably not. Some people lose muscle faster than others. Some exercise and eat well enough to minimize it. This might be for people who can't do that, or whose bodies are particularly vulnerable to the loss.