Is Mounjaro safe?

Mounjaro has been shown to be as safe as the pre-existing GLP-1RA drugs in this class.

They all carry the same warnings and GI-related side effects, which are dose-dependent and happen more frequently during the dose escalation period, are the most common.

Mounjaro does not bring the risk of hypoglycemia when used without a blood sugar reducing medication. The thyroid cancer warning is on all GLP-1 drugs and is related to rats developing this type of cancer; humans have not been shown to have that tendency at all while lab rats have more receptors in their thyroids related to development of this.

Unlike many prior weight loss drugs that had potentially dangerous indications for cardiovascular events, Mounjaro is cardio-protective. As of 9/26/2022, Tirzepatide is in Phase 3 trial studies to be approved on-label for the treatment of:

  • Chronic Heart Failure with preserved ejection fraction,
  • Obstructive Sleep Apnea,
  • Obesity,
  • Non-alcoholic steatohepatitis (NASH) and
  • The reduction of Adverse Cardiovascular outcomes.


“As for safety, tirzepatide therapy did not lead to a higher incidence of all AEs than the placebo or selective GLP-1 receptor agonists, and individual studies indicated that most AEs were mild or moderate in severity [17,18,19,20]. The most prevalent AEs were gastrointestinal (44%), including nausea and diarrhea, and similar AEs observed in current GLP-1 analogs [30]. Moreover, a limited proportion of participants experienced hypoglycemia (3%) and AEs leading to the discontinuation of tirzepatide (7%), most of which are dose-dependent incidences. Ongoing RCTs [5,6,7,9] will confirm whether tirzepatide exhibits long-term safety, and SURPASS-CVOT (NCT04255433) [31] will provide more data on the cardiovascular safety of tirzepatide compared with dulaglutide.”

From: Efficacy and Safety of Tirzepatide in Patients with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Phase II/III Trials
October 2021, Pharmaceuticals (Basel)


Please bear in mind that weight loss very quickly can result in gallbladder problems, gall stones and some folks in those groups have posted that they didn’t eat much, lost too much weight too quickly, and ended up in the hospital for gallbladder removal. This is not from Mounjaro, but from too rapid of weight loss.

Also, dehydration from GI-related problems can occur so stay hydrated.


Other Sources to peruse:

Efficacy and safety of a novel dual GIP and GLP-1 receptor agonist tirzepatide in patients with type 2 diabetes (SURPASS-1): a double-blind, randomised, phase 3 trial.

June 26, 2021 – The Lancet

What about this Thyroid Cancer Warning about Mounjaro? Regarding worries about medullary thyroid cancer:


“In conclusion, compared with placebo or other interventions, GLP-1 receptor agonists did not increase or decrease the risk of thyroid cancer, hyperthyroidism, hypothyroidism, thyroiditis, thyroid mass and goiter. Due to the low incidence of various thyroid disorders, these findings still need to be verified by further studies.”

Use of GLP-1 Receptor Agonists and Occurrence of Thyroid Disorders: a Meta-Analysis of Randomized Controlled Trials

Endocrinology, July 2022


Risk of Malignant Neoplasia with Glucagon-Like Peptide-1 Receptor Agonist Treatment in Patients with Type 2 Diabetes: A Meta-Analysis

Journal of Diabetes Research, July 2019


“There has been some concern—based on results from animal studies—regarding a potential association between the use of GLP-1 RAs and the occurrence of medullary thyroid tumors [47, 48]. However, a meta-analysis of 26 randomized controlled trials (RCTs) of once-weekly GLP-1 RAs showed that, compared to other antidiabetic drugs, once-weekly GLP-1 RAs did not increase the risk of any tumor [49].”

From: A Review of Practical Issues on the Use of Glucagon-Like Peptide-1 Receptor Agonists for the Management of Type 2 Diabetes

Diabetes Therapy, February 2019


Who Shouldn’t Take Mounjaro?

Talk to your physician if you have any of the following conditions, which are contraindicated:

  • Diabetic retinopathy
  • Dehydration
  • Stomach muscle paralysis & decreased function
  • Disease of the gallbladder
  • Decreased kidney function
  • Pancreatitis
  • Medullary thyroid cancer
  • Multiple endocrine neoplasia type 2
  • Family history of medullary thyroid carcinoma
  • Pregnancy