New Blockbuster Type 2 Medication Mounjaro Gets FDA Approval

Over 30 million Americans have type 2 diabetes, and many are not reaching their A1c targets. As an endocrinologist who treats people with type 2, I’m always excited about novel interventions that indicate significant positive outcomes. On May 13th, the FDA granted approval to a potential blockbuster addition to the growing number of type 2 treatments in our arsenal: a new medication called Mounjaro (tirzepatide). With clinical trials demonstrating safety and effectiveness for lowering A1c and promoting weight loss in people with type 2, Eli Lilly’s latest endeavor is poised to be an industry disrupter.

How It Works

This novel therapy builds upon the successes of currently available incretin-based therapies. Incretins are a class of hormones that includes glucagon-like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP). These gut-derived hormones are released in response to food intake, and have the following effects:

  • Promoting insulin release (insulin lowers blood sugar)
  • Blocking glucagon release (glucagon raises blood sugar)
  • Delaying gastric emptying to prevent post-meal highs
  • Promoting a feeling of fullness so you eat less at any given meal

Previously approved incretin-based therapies mimic only the GLP-1 hormone. Due to their effect of blood sugar lowering and weight loss, they are widely used in the treatment of type 2 diabetes and obesity. Examples of such therapies include semaglutide (Ozempic for diabetes, Wegovy for weight loss), liraglutide (Victoza for diabetes, Saxenda for weight loss), and dulaglutide (Trulicty). Because they are released in response to food intake, they are less associated with low blood sugar as is seen with other therapies such as insulin or sulfonylureas (ie- glipizide, glimepiride, glyburide).

Tizepatide, rather, mimics the action of both incretin gut hormones (GLP-1 and GIP) by acting on both of their receptors, and thus has been dubbed a “twincretin.” Similar to some of the other GLP-1 medications, it can be dosed once weekly.

Is This New Combination Safe and Effective?

The SURPASS trials, sponsored by pharmaceutical manufacturer Eli Lilly, assessed Mounjaro (tirzepatide) in people with type 2 diabetes and obesity.

In these trials, tirzepatide was given at doses of 5mg, 10mg, or 15mg. When compared to participants not taking any diabetes medications, those using tirzepatide realized around a 2% decrease in their A1c levels. To underscore the magnitude of this drop, if you had an A1c of 8.5%, it would drop to 6.5% after several months of therapy. In a second trial, when tirzepatide was compared to Ozempic, participants on the novel therapy experienced an even greater decrease in their A1c levels (2.30% vs 1.86% for Ozempic). In a third trial comparing participants using tirzepatide with those on Tresiba (insulin degludec), the tirzepatide group again had greater reductions in A1c levels. Remarkably, 82-93% of the tirzepatide participants in this study reached an A1c level of less than 7%, versus 61% with insulin degludec. As expected, the insulin group experienced more frequent low blood sugar levels and had weight gain, instead of the weight loss experienced with tirzepatide.

In late April 2022, Eli Lilly released preliminary results from the SURMOUNT-1 trial that included overweight and obese patients using tirzepatide who did not have diabetes. Strikingly, at the highest doses and at 72 weeks, participants lost up to 22.5% of their body weight. To underscore the magnitude of the weight loss observed, if you weighed 250 lbs before starting tirzepatide, you would have lost over 56 lbs on average after several months of therapy. This rivals the Novo Nordisk product for weight loss that was FDA approved in June 2021, a GLP-1 mimicker Wegovy (semaglutide), in which people have also been reported to lose over 15% percent of their starting body weight.

Additional trials for tirzepatide will include its effect in people who have non-alcoholic fatty liver disease and congestive heart failure.

Side Effects

As with the GLP-1 mimickers currently on the market, gastrointestinal side effects were commonly reported including nausea, vomiting, diarrhea, and constipation, and they were more often associated with dose increases. Tirzepatide alone was not associated with a significantly increased risk of low blood sugar, particularly when compared to insulin as seen in the SURPASS trials. Further, data demonstrated that many participants reported the gastrointestinal side effects improved with slow titrating over time.

As with all other GLP-1 receptor agonists on the market, tirzepatide can cause thyroid C-cell tumors in rats. It is unknown if this is the case in humans. However, it should not be used by people with a personal or family history of medullary thyroid cancer or multiple endocrine neoplasia type 2. It also is not indicated for use in people with type 1 diabetes.


Despite their effectiveness, many insurance providers do not offer coverage for these medications for the indication of “weight management”, making them cost prohibitive and resultantly inaccessible. I do think things will change for the better in this area. It is always a good idea to check out the company website for assistance programs. When it comes to getting any medication or device that may help you, you must be your own advocate and be persistent with the help of your healthcare provider in your quest to obtain them.

Is Mounjaro Right for You?

As evidenced in the SURPASS trials, this novel GIP/GLP-1 dual-acting hormone therapy is yielding significant improvements in A1c and weight loss. If the gastrointestinal side effects are tolerable, Mounjaro may prove to be the most effective medication available for people living with type 2 diabetes. Check out our video vault for more educational videos on treating type 2 diabetes.

If you have tried Mounjaro, please share your experiences in the comments below.


Additional Resources:

A Dose of Drs. E+P: Say “Buongiorno” to Mounjaro

Weight Loss with GLP-1 RAs

Mounjaro Savings Resources


  1. What is the cost of this. Is it cheaper than Trucity?

  2. Avatar

    Is this medication in the same class as Trucity and Ozempic? I had a bad reaction (pancreatitis) to Byetta that prevents me from using these other medications of the same class.

    • It’s a good question, and the answer is, partially, yes, because Mounjaro does have a GLP-1 receptor agonist component, which is similar to the other two medications. However, it’s also combined with a different medication called GIP. Both are natural hormones found in people with and without diabetes. I would definitely say it’s worth a try because what happened to you on Byetta may never happen to you again on any other formulation, including Trulicity and Ozempic.

  3. Avatar

    Been on this for 8 weeks. Started with 2.5 mg + 1000 mg of metformin and 3mg Glimeperide twice a day. Moning reading dropped, crashed often. After 4 weeks I was put on 5mg and told to stop the Glimeperide and only take the metformin blòod sugar stated to rise got up to 220 after a week. I added back 3 mg of Glimepiride dropped to 92 first morning. Cut it back to 2mg. Morning readings are a low of 94 And a high of 116. Very happy with the results. Next refill is Sunday. Waiting to find out if things will keep the same 5mg or increase to 7.5 and cut other meds. With Medicare part D annual cost is just under $2000.00. Coupon for $25.00 is not allowed if you are on Medicare. It’s expensive but it seems to be working.

    • Avatar

      Thanks for sharing your experience, Barry, and glad you’ve been having good results so far!

  4. Avatar

    is this available in the UK

  5. Avatar

    The medication is working so well to control my blood sugars and I am even losing weight. It’s amazing! My only problem is the awful GI side effects. For about 24 hours each week I am getting stomach pains, burping, nausea, and diarrhea. It’s awful and keeps me awake all night. Anything to help?

    • I would suggest to go back to the previous lower dose, and if you are already on the lower dose, give it every 2 weeks for now.

  6. This medication worked wonders for me for weightloss. I’ve been on it 3 months and had to stop per my doctor and everyone who cares about me. My bgl and bp were dropping. My liver enzymes are outrageously high and concerning to my Dr. I have been in the er twice for gallbladder pain. I have been getting vertigo like crazy. I do not recommend this med. I have 3 kids that I would rather love to see grow up.

  7. Avatar

    Hi I am kind of in a pickle I have been on mounjaro for a month and Dr switched me to Zepbound. Which I had less side effects with Mounjaro. I have done really well losing weight.My problem is the cost. I have Lupus, Sjogrens, Fibromyalgia, and Osteoarthritis so I’m disabled and on Medicare and I have a commercial insurance also and they won’t pay anything! It cost me $1058.00 a month. My Dr’s are hoping loosing weight and getting my BMI lowered might help me to get in remission with my Lupus. Is there any help for me?

Leave a Reply