A new drug called Tirzepatide (sold under the brand name Mounjaro) showed remarkable potential for helping with weight loss, particularly when coupled with healthy lifestyle changes. A Phase III trial which lasted 19 months showed that people who took Mounjaro and made healthy lifestyle changes lost an average of 64lbs (29 kg) more than with a placebo.

Over the past few decades, rates of obesity have soared across many countries. This has led to a surge in related health issues such as diabetes, heart disease, and even certain types of cancer. The crisis is often attributed to a combination of factors, including poor diet, lack of physical activity, and societal structures that promote unhealthy lifestyles.

The obesity crisis isn’t just a personal issue; it also has broad societal implications. Healthcare systems are strained by the growing number of obesity-related illnesses, and the economic costs are substantial in terms of lost productivity and increased healthcare spending.

But, on a personal level, losing weight is often more complicated than simply following the age-old advice to “eat less and move more.” Various factors can make weight loss a challenging endeavor for many people, complicating the path to a healthier lifestyle. Even when people do the right things, they can find it hard to lose weight — as was highlighted by the new trial.

Accelerating weight loss

The study was a randomized, double-blinded, placebo-controlled trial. All 806 participants were overweight or obese, and all underwent a 12-week intensive lifestyle adjustment program. Those who lost at least 5% of their body weight (579 participants) continued in the study and were split into two groups. The first group received Tirzepatide, the second a placebo.

After 72 more weeks, the groups were compared again. Strikingly, the placebo group put on a bit of weight. Meanwhile, the drug group achieved 21.1% mean weight loss.

“While intensive lifestyle intervention is an important part of obesity management, these results underscore the difficulty some people face maintaining weight loss with diet and exercise alone,” said Jeff Emmick, senior vice president of product development at Eli Lilly, the company that developed the drug. Adding tirzepatide to an intensive lifestyle regimen could lead to “greater, longer-lasting weight reduction,” he added.

It’s not just the weight loss. Mounjaro-treated participants reported significant improvements in waist circumference, blood pressure, blood sugar, lipid levels, and self-reported physical functioning. For instance, the mean circumference change was -14.6 cm (5.75 in).

Not a miracle drug

Essentially, Tirzepatide is a peptide that targets the brain’s GIP and GLP-1 receptors — both of which play a crucial role in regulating various physiological processes, particularly related to metabolism and the digestive system. Among other functions, these receptors play a role in appetite regulation.

But as attractive as a weight loss drug sounds, this drug (like any other drug) will not be a panacea against obesity. It is only meant to complement healthy lifestyle changes. In this context, however, it offers great promise. Obesity is a multi-faceted challenge, and it often requires multiple measures. Eating better and exercise are the “classical” recommendations, but having a drug that can supplement them is obviously helpful.

Curiously, this is not a new drug. Tirzepatide was already approved by the FDA in May 2022 for the treatment of Type 2 diabetes. In October 2022, the FDA granted Tirzepatide its Fast Track designation as a weight loss drug.

There were also significant side effects. Around 10% of patients taking the drug dropped out of the study due to adverse events, compared to only 2.1% of placebo participants.

Cautiously optimistic

This is not the first weight loss drug to get a lot of hype in recent months. Ozempic, another drug initially approved against Type 2 diabetes, also shows promise in the fight against obesity.

The results obtained with Ozempic and Tirzepatide present a cautiously optimistic future in our struggle with weight gain. Lifestyle changes remain paramount for tackling obesity, but the journey is often fraught with challenges that make it difficult for many to sustain weight loss over the long term. In this regard, weight loss drugs may offer a much-needed boost, acting as a valuable adjunct to traditional methods of diet and exercise.

Tirzepatide’s dual application, both as a treatment for Type 2 diabetes and now as a promising weight-loss aid, marks it as a multi-purpose tool in our ever-expanding medical arsenal. However, as promising as these results are, it’s crucial to approach this news with a balanced perspective. The drug is not a one-size-fits-all miracle cure, nor is it devoid of drawbacks. The battle against obesity has only just begun.

The study was published in Nature.