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Drug Facts: Dual GIP/GLP-1 RAs


dual GIP and GLP title page with loose medications in background

In May 2022, a new diabetes drug class became FDA approved – Dual GIP/GLP-1 RAs, also being called a “twincretin”. This is the first time since 2013 that a new diabetes drug class has come on the market. Currently, the only drug available in the class is tirzepatide, which is going by the brand name Mounjaro.

GIP and GLP-1 RA chart tirzepatide mounjaro

Curious about how it works? This drug activates receptors in the body for GIP and GLP-1, which are something called incretin hormones. GLP-1 RAs have already been on the market for a while, but this is the first time that a medication is activating another hormone in addition. This is ideal and these hormones seem to work together synergistically. Unless you’ve taken a biology or physiology class lately, this all probably sounds like a foreign language. The main point here is that this medication activates not just one, but two hormones in your body that help lower blood sugar and help decrease appetite. This means the drug works extra well at helping you improve blood sugars and lose weight. A large research trial, called SURPASS, showed it decreased A1C and weight more than the drugs it was compared with.

Tirzepatide is an injectable medication but it is not insulin. It comes in an autoinjector pen, so you do not need to screw on a separate needle or even see the needle for that matter. It is injected only once a week. Like the original GLP-1 RAs, it comes in a variety of doses. You are to take the smallest dose to start with and gradually increase to higher doses. This is done to minimize the gastrointestinal side effects.

This drug is currently only FDA approved to say that it helps control diabetes, but there’s speculation that it will eventually be able to claim that it has heart health benefits and will probably be sold under a different name at some point as a weight loss medication. Lilly, the company that makes Mounjaro, already did a research trial to work on getting the FDA approval to be used as a weight loss medication. In this trial, called SURMOUNT0-1, 9 out of 10 individuals lost weight on the drug and the average weight loss was 15-20% of starting weight, depending on the dose given. For reference, the placebo group lost 3% of starting weight and other prescription drugs on the market generally have a weight loss reduction of 5-15%.


As with the original GLP-1 RAs, side effects can include nausea, diarrhea, vomiting, constipation, indigestion and abdominal pain. The drug shouldn’t cause hypoglycemia, but could if used with insulin or sulfonylureas.