The anti-diabetic drug Ozempic has recently been popularized for its potential as a weight loss aid, gaining notoriety primarily through promotion by social media personalities. Another anti-diabetic drug, Mounjaro, may soon receive similar treatment, as it’s also being touted for its potential to assist in shedding unwanted weight.
In some sense, the rise in popularity of Mounjaro should not come as a surprise. After all, it has much in common with Ozempic, at least on the surface. However, a deeper dive may reveal that Mounjaro could hold the same potential as Ozempic, and then some. In this article, we explore whether the Mounjaro hype holds any weight, and why you might want to keep this one on your radar.
What is Mounjaro?
Mounjaro (tirzepatide) is a recently FDA-approved addition to the existing family of anti-diabetic medications, a broad class of drugs which offer some therapeutic benefit in the treatment of type 1 or type 2 diabetes. More specifically, Mounjaro is approved for the treatment of type 2 diabetes in adults, as it has been shown to elicit multiple beneficial effects in many patients who receive it regularly. These can include a selective boost in insulin production in response to rising blood sugar levels, a decrease in sugar released from the liver, and a decreased appetite overall.
Together, these effects of Mounjaro can help type 2 diabetics respond appropriately to insulin and increase the amount of time their blood sugar levels spend within an acceptable range. These effects have also been noted for their potential to support weight loss in diabetics and non-diabetics alike. However, neither of these facts are unique to Mounjaro; drugs like semaglutide (the active chemical in Ozempic and Wegovy) also aid in the treatment of type 2 diabetes, and have already been approved for the treatment of obesity. The two are even both administered in nearly identical fashion, through weekly (or otherwise regular) injections. Given its similarity to existing offerings, then, what makes Mounjaro so noteworthy?
Comparison to Existing Offerings
Ozempic and Mounjaro are both GLP-1 receptor agonists, meaning they both mimic the activity of the naturally occurring hormone GLP-1 at an amplified level. However, Mounjaro goes a step further, in that it also interacts with the GIP system, another hormone linked to metabolism and insulin sensitivity. In fact, Mounjaro is the first and only medication to simultaneously act on both hormone receptors, making it a unique offering for now.
To understand the difference between GLP-1 and GIP, and the corresponding advantages of acting on both receptors, it is helpful to understand these hormones in their natural context. Both naturally occurring hormones belong to a hormone category known as the “incretins”, meaning they are normally secreted in response to eating glucose in order to enhance the corresponding release of insulin. Though both hormones contribute to this effect, GIP likely plays a more significant role, claiming responsibility for nearly two thirds of the incretin effect.
Though their primary functions seem to be as incretin hormones, these hormones have also been found to have various secondary effects which contribute to their utility in a medical context. For example, GIP receptors have been found in areas of the brain associated with appetite control, suggesting that activating these receptors may increase perceptions of satiety and thus limit food intake. Additionally, whereas the increased insulin sensitivity observed in many patients taking GLP-1 receptor agonists may be a simple consequence of a reduced body weight, some studies have shown that GIP may have a more direct impact on insulin sensitivity.
The science behind these endocrine messengers is complex, but the key takeaways here are as follows. First, though GLP-1 and GIP are similar in their primary effects, activating both receptors may have an additive effect that could increase the overall efficacy of treatment. And, each hormone may possess secondary functions that further contribute to the overall therapeutic goals through multiple mechanisms of action. Therefore, at least in theory, one should expect a GLP-1 and GIP receptor agonist like Mounjaro to out-perform a mere GLP-1 receptor agonist like Ozempic. But does the research support this hypothesis?
The Results Are (Sort-of) In
Though research data do not yet paint a complete picture where weight loss is concerned, at least one clinical trial has shown that patients receiving Mounjaro lost 7-17% more body fat compared to patients taking Wegovy and Saxenda, respectively. Though a single study should not be seen as conclusive, these results might suggest that Mounjaro yields a greater overall efficacy in inducing weight loss, which would seem to align with its dual mechanisms of action.
Mounjaro appears to also take the edge with respect to reducing A1C levels in diabetic patients, at least according to one study. While A1C is not typically used as a metric for monitoring the progress of obese patients, this result may add further weight behind the notion that Mounjaro can deliver more significant effects than its GLP-1 receptor agonist alternatives, whether in treating obesity or diabetes.
However, these results are not conclusive, and we must underline the importance of deferring to expert interpretations of research data. Future studies are needed to address gaps in the existing research, such as comparing the effects of both drugs at various dosages and testing existing results for repeatability. Nevertheless, these early outcomes do offer exciting food for speculation about future revelations.
Not (Yet) Approved for Weight Loss
Given the lack of complete data, including insufficient clinical trial data, Mounjaro currently remains FDA-approved only for the treatment of type 2 diabetes in adults. However, some doctors are reportedly prescribing the medication off-label for the treatment of obesity, similar to the prescription of semaglutide (as Ozempic) prior to its approval by the FDA for the treatment of obesity (as Wegovy).
Recent studies and clinical trials have been conducted to assess whether the claims about Mounjaro’s weight loss potential can stand up to the rigor of FDA approval. To summarize, their results seem encouraging, though the clinical trial process has yet to conclude. One study, for example, reported that patients given Mounjaro achieved “substantial and sustained” weight loss over the study’s duration, regardless of the dosage they were given.
Though the FDA has yet to provide their stamp of approval, they did grant a fast-track designation for approval in October, 2022, suggesting that Mounjaro could be approved for weight loss as early as this year. This bodes well for the prospect of Mounjaro joining the ranks of anti-diabetes medications that have been approved for the secondary purpose of supplementing a weight loss regimen. Until then, some doctors may continue to prescribe the medication off-label as they deem appropriate.
Potential Side Effects
Of course, like all medications, including other anti-diabetics prescribed for weight loss, Mounjaro has the potential to cause a range of side effects in its users. Caution and diligence are therefore crucial for any individual who is starting or maintaining a course of treatment on Mounjaro. Be sure to look for any unusual symptoms, which may include those listed in this section, and report them to your doctor. Remember, everyone’s body is different, and no two people should expect to experience identical reactions to Mounjaro.
Because of its effects on digestion, commonly reported side effects of Mounjaro often involve some form of gastro-intestinal distress. This can take the form of diarrhea, constipation, nausea or vomiting, indigestion, stomach pain, and a weak appetite. Users experiencing any side effects should discuss with their doctor whether continuing their treatment would be medically advisable, or whether an alternative approach may be best.
Mounjaro can pose a risk for more serious complications, particularly in patients with medical histories involving certain thyroid cancers or other endocrine syndromes. As such, Mounjaro should not be taken by these individuals for any reason. Ensure that your doctor has accurate and up-to-date information about your personal and family health history before advising you on appropriate medical treatments.
Recent months have seen a flurry of excitement around innovative new drugs promising a boost for obese Americans looking to drop some unwanted pounds. Ozempic has been perhaps the most notable example to date, though names like Wegovy and Rybelsus were quick to enter the public consciousness shortly after. Now, with research showing early but promising results, Mounjaro may be the new talk of the town when it comes to an adjunct to diet and exercise in pursuit of weight loss.
Between its innovative dual mechanisms of action, its availability during a time of shortage for many alternatives, and its potentially lower price tag, Mounjaro certainly stands to make quite a name for itself. FDA approvals and further research will be updates to watch for in the coming months, but in the meantime, consider speaking to your doctor if you feel that off-label Mounjaro use for weight loss might interest you.