Semaglutide (Ozempic) vs Tirzepatide (Mounjaro)

The names are complicated but what they do is the same – Glucagon-Like Peptide 1 ("GLP1") receptor agonists suppress hunger and help with weight loss.

There are many companies making them too – Ozempic is produced by Novo Nordisk, and Mounjaro is made by Eli Lilly (these are the two biggest players in the GLP1 space, as of right now).

It can be hard to tell the difference between these drugs (and their ingredients), and the effects they might have or not have on the body. Let's make it easy.

Active Ingredients/How it works

Ozempic is the most popular GLP1 Receptor Agonist. In plain English, it's a drug that mimics the a naturally occurring hormone in your body which your body uses to signal fullness ("satiety").

Mounjaro is a slightly different formulation – it contains both a GLP1 receptor agonist and a Glucose-dependent Insulinotropic Polypeptide ("GIP"). Both GLP1s and GIP encourage your body to produce insulin.

You can read more of the research on what makes "dual agonists" like Mounjaro special below:

The Emerging Role of Dual GLP-1 and GIP Receptor Agonists in Glycemic Management and Cardiovascular Risk Reduction

The incretin pathway is a self-regulating feedback system connecting the gut with the brain, pancreas, and liver. Its predominant action is on the postprandial glucose levels, with extraglycemic effects on fat metabolism and endovascular function. Of…

PubMed Central (PMC)Ali A Rizvi

Both GLP1s (Ozempic) and GLP1 + GIP "dual agonists" (Mounjaro) do the roughly similar things in the body – they encourage the production of Insulin, and act as synthetic versions of hormones your body produces naturally when you are full.

Known side effects

The known side effects of Ozempic and Mounjaro don't differ all that much.

In general, all the common and serious side effects are shared between both drugs.

Both (Ozempic and Mounjaro)

• Common side effects
  • Nausea
  • Vomitting
  • Diarrhea
  • Stomach (abdominal) pain
  • Constipation
• Serious, rarer side effects (i.e. stop using and contact your health care provider)
  • Inflammation of your pancreas (pancreatitis), severe stomach pain
  • Low blood sugar (hypoglycemia) – various symptoms including dizziness, lightheadedness, blurred vision, anxiety, and more.
  • Serious Allergic reactions
  • Kidney failure and kidney problems
  • Changes in vision
  • Gallbladder problems – upper stomach pain, fever, jaundice, clay colored stools

Mounjaro only

• Common side effects
  • Decreased appetite (this is somewhat expected)
• Indigestion

Approvals

Ozempic is FDA approved for Type 2 diabetes treatment (it was approved in 2017):

Ozempic Drug Trial Snapshot

Drug Trial Snapshot

FDACenter for Drug Evaluation and Research

See also the "Orange book" entry for Semaglutide 2.5mg

Mounjaro (Tirzepatide) is approved for Type 2 diabetes treatment as well:

Drug Trials Snapshots: MOUNJARO

Drug Trials Snapshots: MOUNJARO

FDACenter for Drug Evaluation and Research

See also the "Orange book" entry for Tirzepatide 2.5mg

But remember – at present neither Ozempic or Mounjaro are approved for weight control – only Wegovy is:

FDA Approves New Drug Treatment for Chronic Weight Management, First Since 2014

FDA approves Wegovy (semaglutide) injection for chronic weight management in adults with obesity or overweight with at least one weight-related condition.

FDAOffice of the Commissioner

Wegovy is also approved for heart disease:

FDA Approves First Treatment to Reduce Risk of Serious Heart Problems Specifically in Adults with Obesity or Overweight

The FDA approved a new use for a drug to reduce the risk of serious heart problems in adults with cardiovascular disease and either obesity or overweight.

FDAOffice of the Commissioner

Wegovy is more similar to Ozempic in that it is only a GLP1 receptor agonist (Semaglutide) than it is to Mounjaro. It's not an unreasonable leap to think that the other drugs with the same active ingredients have similar effects.