Weight loss jabs, such as Ozempic, Wegovy, and Mounjaro, initially developed for diabetes management, have gained widespread popularity for their rapid weight loss effects achieved by significantly reducing appetite. Millions of individuals in the UK and US are now using these medications, both through official prescriptions and private channels, to shed pounds. However, alongside their efficacy, a growing body of research and user reports highlight significant side effects, including muscle wasting, dramatic hair loss, and potentially life-threatening surgical complications.

Recent US research investigating semaglutide, the active ingredient in Wegovy and Ozempic, suggests these powerful drugs may lead to muscle shrinkage. While doctors have previously cautioned that this could result in a metabolically 'fatter' body composition—a higher fat-to-muscle percentage—raising the risk of weight regain, new findings in mice indicate that most of this muscle loss originates not from skeletal muscles surrounding bones and joints, but from other metabolically active tissues like the liver. Dr. Ran Hee Choi, an expert in nutrition at the University of Utah, noted that loss of mass in organs like the liver is an expected part of healthy weight loss. Although Ozempic-induced weight loss decreased overall lean muscle mass by about 10 percent in mice, skeletal muscles only shrunk by approximately six percent, while muscle from other tissues like the liver saw nearly a 50 percent reduction. Despite this, some muscle strength decreased, even when muscle size remained constant, raising concerns for adults over 60 already at higher risk of muscle loss and reduced mobility. Experts, however, urge caution in extrapolating mouse study findings directly to humans, emphasizing the need for further human research to understand the impact on muscle strength and performance.

Another prevalent and distressing side effect reported by numerous users, particularly with drugs like Mounjaro, is dramatic hair loss. While initial fears might point to the drug itself, leading experts, like Dr. Ed Robinson, clarify that the medication is not the direct cause. Instead, the problem stems from rapid weight loss induced by suppressed appetite, which often leads to severe calorie restriction and consequent nutritional deficiencies. Weight loss jabs silence 'food noise,' prompting users to eat significantly less, often picking at meals or consuming nutritionally poor snacks. This reduced calorie intake means the body may not receive essential nutrients like fats, vitamins (D, A, K, E, B12), minerals (iron, zinc, magnesium), and especially protein, which is crucial for hair formation (keratin). Such deficiencies can lead to hair becoming thinner, more brittle, and can trigger a stress-induced hair loss condition known as telogen effluvium. In this condition, hair follicles prematurely enter a shedding phase due to stress or malnutrition, and without adequate nutrients to grow new hairs, baldness or thinning patches can appear. Users like Nour Mansour and Grace Parkin experienced significant hair loss but saw improvement after adjusting their diets and taking supplements under medical guidance. Experts stress the importance of maintaining a balanced, nutrient-rich diet, even with calorie restriction, and seeking professional advice if hair loss persists.

Beyond physiological side effects, a critical safety concern for individuals on weight loss jabs involves surgical procedures. Dr. Mo Akhavani, a London-based consultant plastic surgeon, warns that these medications significantly delay gastric emptying—the process by which the stomach empties its contents. This poses a severe risk of aspiration pneumonia, a life-threatening lung infection caused by inhaling food or liquid, if food remains in the stomach during general anesthesia. Patients are typically advised to fast for at least six hours before surgery, but for those on weight loss jabs, the standard fasting period may be insufficient. Studies have shown that these jabs can increase the risk of aspiration by 33 percent. Doctors recommend discontinuing the medication for two weeks or more prior to surgery. A major problem is that patients often 'genuinely forget' to disclose their use of these jabs, as they have become a routine part of their daily lives. Medical professionals emphasize the paramount importance of informing doctors about all medications, including weight loss jabs, before any procedure requiring anesthesia.

The overall landscape of weight loss jabs reveals a complex picture of transformative potential coupled with significant challenges. Other reported side effects include nausea, constipation, decreased libido, reduced interest in alcohol, and bloating. While there have been reports of fatalities linked to these drugs, direct causation remains unproven, though regulators have launched probes into specific adverse events like pancreatitis. Despite these concerns, demand for weight loss treatments continues to surge, with new innovations like the daily pill orforglipron emerging. Given the rapid increase in users and the spectrum of potential side effects, adherence to strict medical supervision, understanding the importance of balanced nutrition, and transparent communication with healthcare providers are crucial for ensuring patient safety and maximizing the benefits of these powerful medications.