Reasons Wegovy and Mounjaro May Not Work and Criteria for Identifying Non-Responders

Recently, injection treatments such as Wegovy and Mounjaro have been attracting a lot of attention in obesity treatment.

Many people start with the expectation that one diet injection will help them lose weight, but in reality, there are many cases where weight does not decrease as much as expected or the effect is not felt.

Why do people respond differently to the same diet injection? In this article, we will look in detail at why the effectiveness of obesity medications differs from person to person and at the criteria for identifying non-responders.

Through this, we hope to help those who are starting or considering diet injections approach them properly with realistic expectations.

Differences Between Wegovy and Mounjaro

Classification	Wegovy (semaglutide)	Mounjaro (tirzepatide)
Mechanism of action	GLP-1 (single action)	GLP-1 + GIP (dual action)
Initial response speed	Relatively gradual (adjustment period needed)	Fast

Wegovy stimulates certain receptors in the brain to reduce appetite, while Mounjaro simultaneously stimulates appetite-suppressing hormone receptors and the gastric inhibitory polypeptide receptor.

The Real Reasons Wegovy and Mounjaro May Not Work Well

✔️ Genetic differences and receptor sensitivity

People vary in how they respond to GLP-1 signaling. Some have lower sensitivity to the medication, so the appetite-suppressing effect may appear weak.

👉 In such cases, people often feel that the "medicine does not work," but in reality, it is often due to constitutional differences rather than a problem with the drug.

✔️ Influence of the brain’s reward circuitry

Appetite is thought to be deeply connected not just to simple hunger, but also to the dopamine reward system.

📌 When the pleasure of eating is felt very strongly 📌 When food is used as a reward in stressful situations

👉 In these cases, the urge to eat may be stronger than the medication’s appetite-suppressing effect.

✔️ Metabolic status and hormonal issues (secondary obesity)

If you have the following conditions, the effectiveness of the medication may be limited.

📌 Insulin resistance

👉 In such cases, it cannot be solved by injection alone, and correction of the underlying condition is also necessary. That is why, at our clinic, we sometimes check the body’s condition first through blood tests.

✔️ Dosage and adjustment-period issues

Wegovy and Mounjaro are used with a gradual dose-escalation approach, starting at a low dose.

📌 The effect may be minimal at the initial low-dose stage 📌 Many people give up before reaching a sufficient dose

👉 If you use the medication without lifestyle changes, weight loss of around 2% may make the effect feel less noticeable.

✔️ The gap between expectations and actual results

Many people start with the expectation that "once I get the injection, my appetite will disappear completely." However, in reality, appetite decreases gradually and blood sugar control improves progressively.

👉 Because of this difference, many people feel that it has "failed" even when it is actually working.

Criteria for Evaluating Non-Responders

In general, if after 12 to 16 weeks of use weight loss is less than 5%, it can be considered medically a "non-responder." However, in actual clinical practice, rather than a complete non-responder who does not respond to the drug at all, cases where the expected effect is not achieved due to specific factors are much more common.

Non-responders may exist due to genetic factors, eating habits, and insulin resistance, but causes such as drug tolerance, brain appetite-regulation gene activity, and stress-related binge eating can also be considered, so dose adjustment and switching medications may be necessary.

Therefore, if non-response is suspected, do not change the dosing method on your own. You must consult with medical staff and establish again the optimal strategy that is right for you.

Things to Watch Out for When Evaluating Diet Injection Non-Responders

✨ Drug half-life and blood concentration accumulation

Wegovy and Mounjaro have a half-life of about 5 days, so over a certain period the concentration in the body gradually accumulates. At the beginning, the blood concentration may not rise sufficiently, so the effect may appear weak. In other words, it may be a state where the medication has not yet reached the stage where it can work properly, so it is too early to judge this as non-response.

✨ Confusing false hunger with real hunger

The medication is effective at reducing physical hunger, but stress, habitual eating, and emotional hunger can be difficult to control.

✨ Storage temperature and usage errors

The GLP-1 system requires refrigerated storage. If it has been stored improperly due to long exposure to room temperature or repeated temperature fluctuations, its stability may decrease and the effect may be reduced.

Choosing the Right Injection for You Is Important

Wegovy works by gently lowering appetite and helping you feel full for longer, naturally reducing food intake. So it tends to be relatively well-suited for cases where weight gain is due to habitual snacking, frequent eating, or late-night eating. Mounjaro, on the other hand, has a stronger appetite-suppressing effect and a faster rate of weight loss, and because it is especially excellent at improving glucose metabolism, it may be more suitable for people with severe obesity or those who need blood sugar control.

Because the pathways of action differ even among the same obesity medications, and the way each person responds to those pathways also differs, a personalized prescription based on the individual’s condition is absolutely necessary rather than applying the same approach to everyone. For example, the approach should be different for someone who simply eats a lot versus someone with stress-related binge eating, and when insulin resistance or blood sugar issues are present, choosing the medication becomes even more important.

Therefore, when choosing a diet injection, it is safer and more efficient for weight loss to accurately select the medication that suits your body rather than choosing a trending drug or the one that worked for someone else.

Just because your weight is not dropping as much as you expected right now, you do not need to immediately conclude, "I am someone for whom it does not work."

That is because obesity treatment injections are not a process in which weight drops immediately upon injection; rather, they are a treatment in which your body’s adaptation to and response to the medication takes place together. Since the speed of response to medication, constitutional characteristics, BMI, and whether you have accompanying conditions all differ from person to person, it is very natural that results will differ even when the same medication is used.

At our clinic, we are running the DT7 program for non-responders, and even those who did not see results with Wegovy or Mounjaro are highly satisfied with their weight loss.

Through InBody measurements and blood tests, we accurately check each individual’s current condition, and based on 충분한 상담, we set the treatment direction through multifaceted solutions so that we can help you safely reach the results you want.