Considering that more than 2 out of every 5 American adults suffer from obesity, it’s hardly surprising that promising weight-loss medications are in high demand. While it might be tempting to think that simply “eating less” could solve overweight and obesity for the majority of people suffering from these conditions, the truth is infinitely more complex.

Overweight and obesity, chronic diseases caused by a combination of genetic, environmental, and social factors, are associated with a host of comorbidities including Type 2 Diabetes, cardiovascular disease, high blood pressure, osteoarthritis, sleep apnea, and many more. In fact, more than 2.8 million people die globally every year from obesity-related conditions and obesity is a leading cause of death in the U.S.

In recent years, injectable anti-diabetic and weight loss drugs known as GLP-1 receptor agonists have taken the world by storm—both for their ability to effectively lower and control blood sugar levels and for their unprecedented weight loss potential. Celebrities, social media influencers, and medical professionals alike have touted the groundbreaking weight loss results of medications like Saxenda (liraglutide), Ozempic and Wegovy (semaglutide), and more.

The most recent injectable, anti-diabetic drug to hit the market has been tirzepatide, a first-in-class, dual-agonist medication that is marketed under the brand names Mounjaro and Zepbound.

Tirzepatide garnered immediate attention in 2022 when results from its clinical trials were published, revealing that participants lost up to 26.6% of their body weight (an average of 60 lbs.) in a less-than-two-year period. Late in 2023, tirzepatide was officially FDA-approved for weight loss under the brand name Zepbound (though its identical counterpart, Mounjaro, had already been popular as an off-label weight loss drug since it was approved for Type 2 Diabetes management in 2022).

If you’re among the many Americans who can’t wait to get your hands on Mounjaro, you’re certainly not alone. With the wide publicization of weight loss outcomes that approach those seen with some bariatric surgeries and surpass those of any other injectable medications, demand for tirzepatide drugs is at an all-time high.

That being said, if you’re considering taking Mounjaro for weight loss or have recently been prescribed the drug, you may be wondering about the answer to a very important question, namely: When will I start to see results?

Below, we’ve put together an overview of how Mounjaro works and what the average weight loss timeline looks like on the drug. Keep in mind that every patient’s weight loss journey is unique and that the information provided in this article doesn’t constitute medical advice. To learn more about how Mounjaro may help you achieve your personal weight loss goals, speak directly with your doctor or healthcare provider.

Key Takeaways

  • Mounjaro (tirzepatide) is an injectable, anti-diabetic drug that is often prescribed off-label for weight loss or chronic weight management. (Its counterpart, Zepbound, has been approved for this purpose since late 2023).
  • Patients taking tirzepatide drugs typically shed some pounds within the first few weeks on the drug, but the greatest weight loss usually occurs starting after approximately 12 weeks.
  • Mounjaro and Zepbound are not stand-alone drugs. They are most effective in combination with lifestyle changes including regular exercise and a healthy diet.
  • Stopping Mounjaro can cause weight regain to occur, but this can be mitigated with an active, healthy lifestyle as well as other supports and interventions.
  • Mounjaro and Zepbound are prescription medications that should only be taken under the supervision of a medical professional. Never start or stop taking these drugs without first consulting your doctor or healthcare provider.

How Mounjaro Works

Mounjaro (active ingredient tirzepatide) is a prescription drug manufactured by pharmaceutical giant Eli Lilly. It’s a once-weekly injectable medication that is meant to be used as an adjunct to a healthy lifestyle, including regular exercise and a nutritionally balanced diet.

Like Ozempic, Wegovy, Saxenda, and many other injectable anti-diabetic and/or weight loss medications, Mounjaro is a GLP-1 receptor agonist. In simple terms, this means that it mimics a naturally occurring gut hormone known as glucagon-like peptide 1 (GLP-1) and binds to its receptor sites in response to the intake of carbohydrates and other foods.

In addition to mimicking the hormone GLP-1, Mounjaro mimics and binds to the receptor sites of another hormone as well—the incretin hormone GIP (glucose-dependent insulinotropic polypeptide). This dual mechanism of action differentiates it from other GLP-1 medications and has established it as a first-in-class GLP-1 and GIP receptor agonist.

The relationship between blood sugar control and weight loss is highly intertwined and Mounjaro has an impact on both. Let’s take a closer look:

For Diabetes

Mounjaro was first FDA-approved for Type 2 Diabetes management in adults in 2022. It is highly effective in lowering and controlling blood sugar levels post-meal times as well as throughout the day and night, which it does via the following mechanisms of action:

  • Mounjaro stimulates natural insulin secretion and release in the pancreas.
  • It inhibits the production and release of sugars from the liver.
  • It helps to increase insulin sensitivity in the body’s cells and tissues. (When cells and tissues are sensitive and responsive to insulin, they can effectively take in and metabolize sugars from the bloodstream, thus keeping blood glucose levels within an optimal range).

For Weight Loss

Mounjaro is technically only approved for the treatment of Type 2 Diabetes, though it has been (and continues to be) frequently prescribed off-label for weight loss by many doctors who believe that it benefits overweight and obese patients. In late 2023, tirzepatide was officially FDA-approved for weight loss and chronic weight management under the brand name Zepbound.

Zepbound is identical to Mounjaro but is specifically indicated for patients with or without Type 2 Diabetes who are overweight (BMI over 27) with one or more related health conditions or obese (BMI over 30). Mounjaro and Zepbound impact weight loss in the following ways:

  • Tirzepatide slows down gastric emptying (the rate at which food leaves the stomach) and the entire digestive process. This helps patients naturally feel fuller for longer.
  • It impacts the brain’s appetite centers, helping to reduce cravings and interrupt habitual eating patterns.

Average Weight Loss Reported

In clinical trials, obese adults taking once-weekly Mounjaro injections lost as much as 26.6% of their starting body weight at the highest dosage levels of the drug. That being said, patients who take the drug on their own without receiving the same type of intensive lifestyle intervention support that was provided during trials may not experience such dramatic weight loss results.

Mounjaro Weight Loss by Week

As with any weight loss approach, shedding pounds on Mounjaro is bound to have its ups and downs. It’s only natural that certain weeks may see exceptional weight loss results while others may plateau. For these reasons, it is recommended not to measure your weight loss success with Mounjaro on a week-by-week basis, but rather over the longer term.

That being said, here are some broad weight loss trends to keep in mind when starting on Mounjaro. A large number of patients experience the following:

  • Many patients experience modest weight loss results immediately upon starting Mounjaro. The drug reduces hunger levels right away, which may result in a 2-4% decrease in body weight over the first few weeks.
  • After about 4 weeks, the drug will reach a steady state in the body (not fluctuate) and dosage increases can begin. Your doctor will tell you exactly when and how to increase your intake of Mounjaro.
  • After about 3 months (12 weeks) on Mounjaro, patients often notice more substantial weight loss results. At this point, your doctor may continue to increase your dose or recommend that you maintain your dose at its current level.

Overall Weight Loss Results

Anecdotal reports suggest that many overweight and obese patients who inject tirzepatide weekly lose between 10-20% of their starting weight over time, but weight loss outcomes will vary significantly from patient to patient. The precise amount of weight each individual may lose on the drug depends on a variety of factors, including:

  • Their age and overall health
  • Their medical history
  • Their personal body chemistry
  • Their lifestyle (activity level, diet habits)
  • How consistently they take the medication
  • Their maintenance dose of the medication
  • How long they take the medication for
  • Their weight loss goals
  • The side effects they experience from the drug

Before and After Pictures

**Follow format used in Discover Magazine article

Tara Rothenhoefer

Tara Rothenhoefer participated in a Mounjaro clinical trial and lost 75 lbs. in the first six months on the drug and more than 180 lbs. in total. She continues to take a maintenance dose every week to prevent unwanted weight regain.

Charles Barkley

Celebrity Charles Barkley has undergone Mounjaro treatment with impressive results. He’s now 60 lbs. lighter than when he started taking the medication but emphasizes that his weight loss journey has involved regular physical activity.

Mari C (mcruzita979)

Mari C lost more than 80 lbs. over the course of one year using a combination of exercise, dietary changes, and weekly Mounjaro injections. She notes that the majority of her weight loss took place within the first six months.

Emily (emsuz1)

Emily has lost upwards of 150 lbs. on Mounjaro. Though she is thrilled with her outcomes, she is now considering surgery to address excess skin.

Matthew Barlow

Matthew Barlow lost more than 100 lbs. during his first 5 months taking Mounjaro and wants people to know that, though the drug is more often targeted toward women, it can be a life-changer for men looking to lose excess weight as well.

Maintaining the Weight Loss

Obesity and Type 2 Diabetes are chronic conditions. Therefore, it’s not surprising that both Mounjaro and Zepbound are long-term medications intended to be taken throughout a lifetime. For many patients, this is not a concern. For others, however, the prospect of taking any medication well into the future is unsettling. Side effects or other health concerns can also make long-term use of tirzepatide drugs an impossibility in certain cases.

Some patients prefer the idea of kickstarting their weight loss journey with Mounjaro and then getting off the drug once they’ve reached their target weight and/or are feeling ready and prepared to maintain their weight loss goals on their own. But this is often easier said than done. Weight regain after stopping Mounjaro is common and can often occur even despite hard work. That being said, the best ways to keep weight off after stopping Mounjaro include:

  • Maintaining a nutritious, calorie-deficient diet
  • Exercising regularly (30 minutes per day is ideal)
  • Drinking plenty of water
  • Seeking support from friends, family, and/or a professional to keep you on track with your weight management goals

If you are struggling to keep weight off after stopping Mounjaro, speak with your doctor or healthcare provider for suggestions on how best to continue your weight loss journey.

Mounjaro Side Effects

All drugs have potential side effects, and tirzepatide drugs are no exception. Some of the side effects associated with Mounjaro are listed below. For more detailed information about side effects, consult the medication’s prescribing information.

Common Side Effects

  • Gastrointestinal issues including nausea, vomiting, abdominal pain, constipation, diarrhea, decreased appetite
  • Injection site reactions

Serious Side Effects

  • Allergic reactions
  • Hypoglycemia
  • Kidney, gallbladder, or pancreas problems
  • Vision problems
  • Thyroid tumors


  • Pregnancy or breastfeeding
  • Personal or family history of certain types of thyroid cancer
  • Type 1 Diabetes
  • Existing severe digestive problems
  • History of pancreatitis, diabetic retinopathy, or serious kidney or gallbladder issues
  • Less than 18 years of age

Where To Get Mounjaro

Mounjaro and Zepbound are both prescription drugs. As long as you have a valid prescription written by a doctor, you should be able to purchase Mounjaro at a wide variety of different local pharmacies in your area.

That being said, the monthly cost of Mounjaro is high (without insurance coverage it can be well over 1000 USD per month), and finding the most economical way to source Mounjaro is a priority for many patients. Purchasing Mounjaro online is often more affordable than purchasing it in person at a brick-and-mortar pharmacy and sourcing medications online from Canada can often reduce costs even further.

At, our professional prescription referral service is based entirely on shipping high-quality medications to Americans at affordable prices. Our exceptionally qualified team is here to help and, whether you’re placing your first order with us or your hundredth, you can rest assured that the experience will meet and exceed your expectations. We encourage you to reach out to us for information and support at any moment.


To conclude, Mounjaro is a popular Type 2 Diabetes drug that is often prescribed off-label for weight loss. Its identical counterpart, Zepbound, was officially approved for this purpose in late 2023. Though every patient’s weight loss journey on Mounjaro will be unique, many patients experience modest weight loss almost immediately upon starting the drug followed by more notable results after several weeks.

Ready to place an order for affordable, high-quality Canadian Mounjaro and have it delivered conveniently to your door? Reach out to us directly at today!

About the Author

Ida Edlweiss Gumpal is a licensed Pharmacist and medical writer. She took her internships at Mercury Drug Corporation, Inc., a Hospital internship at De Vera Medical Center, Inc., and a Manufacturing internship at Philmed Laboratories, Inc. She has plans on attending medical school with the goal of specializing in Neurosurgery or Cardiothoracic surgery.