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The Impact of New Medications for Obesity

A New Therapeutic Paradigm

In recent years, obesity has shifted from being seen as a matter of “willpower,” to be solved only with diet and exercise, to being recognized as a chronic disease with complex biological roots. This new perspective coincides with the arrival of very powerful medications, GLP-1 agonists and combinations, which act on the brain and metabolism, helping to reduce weight and associated complications in a sustained way. The best known are semaglutide and tirzepatide, and even more effective drugs are already in development. In 2023, a major study (SELECT) showed that semaglutide not only promotes weight loss, but also reduces the risk of heart attack and cardiovascular death in people with obesity. So much so that in 2024 the FDA expanded its use for the prevention of heart disease—a decisive step that changes the rules of the game.

Effectiveness and Maintenance

Tirzepatide achieves weight loss of between 15% and 21% in just over a year, and recent comparisons suggest it may be more effective than semaglutide. Over the longer term, some weight tends to be regained, but the benefits remain if treatment continues. New molecules such as retatrutide or amycretin point to weight reductions close to those achieved with bariatric surgery, opening a very promising future.

What Will It Mean for Global Health?

If these medications are used widely and sustainably, they could significantly reduce the incidence of type 2 diabetes, hypertension, sleep apnea, and heart disease. The approval of semaglutide for cardiovascular prevention has already changed medical practice: cardiologists now prescribe obesity drugs as part of standard treatment. However, access is not equitable: in the United States, for example, only some states cover the cost, and in countries with fewer resources access is even more difficult.

Studies show that these drugs can be cost-effective, meaning that their health benefits justify the expense. But current prices are very high, and at scale health systems could see their budgets grow worryingly. The debate is whether long-term savings (fewer heart attacks, fewer diabetes cases) will offset the immediate cost.

Safety and Long-Term Effects

The most common side effects are digestive (nausea, vomiting, diarrhea, or constipation). Gallstones may also occur, and more rarely, pancreatitis. Some patients lose muscle mass along with fat, which makes it necessary to combine treatment with strength training and good nutrition. Another challenge is that when the medication is stopped, weight often comes back, reinforcing the idea that this is a chronic treatment. There are still no safety data beyond 5 years, so close follow-up will be essential.

The most reasonable approach is to prioritize use in high-risk patients, such as those who already have cardiovascular disease or type 2 diabetes. Health systems will need to look for innovative payment models, for example linking cost to results, and ensure equitable access. It will also be essential to accompany treatment with lifestyle changes and exercise programs.

The Future

If prices drop, coverage expands, and safety is confirmed, these medications may become an intermediate option between population-level prevention and bariatric surgery. Their potential impact on reducing heart attacks, diabetes, and disability is enormous. But if clear policies on access and patient selection are not put in place, the risk is increased spending without fully capturing the benefits.

The Black Market and Fraud

The success of these drugs has also brought problems: counterfeit copies of semaglutide and tirzepatide have appeared on the internet, and unauthorized pharmacies offer “compounded” preparations that may be ineffective or dangerous. In addition, many over-the-counter supplements are adulterated with risky substances, such as sibutramine. The dangers include uncertain dosages, contamination, loss of efficacy, and serious side effects. The recommendation is clear: only buy with a prescription at authorized pharmacies, check packaging and batch numbers, and report any suspicious product to health authorities.