The tirzepatide mechanism of action (MOA) is similar to that of liraglutide and semaglutide, two other highly successful weight-loss medications. However, tirzepatide is a first-in-class medication because it binds to two receptors instead of one, allowing users to achieve even greater weight loss.It seems like suddenly, there are a plethora of weight-loss medications available to treat obesity. This sudden increase in available options can make it difficult to understand why one medication may be superior to another. The newness of these medications leads many to wonder how tirzepatide works. How does tirzepatide work for weight loss and as a type 2 diabetes and obesity treatment?
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What is tirzepatide?
Tirzepatide is the first weight loss medication that is a dual-acting glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) receptor agonist. Semaglutide and liraglutide only target the GLP-1 receptor.
GLP-1 and GIP hormones are secreted from the intestine after you eat. These hormones bind to their receptors in the same way a key fits into a lock. Similar to a lock and key, when a hormone such as GLP-1 or GIP binds to its receptors, it can cause your body’s tissues and organs to produce products such as insulin, change how the brain perceives hunger, or even cause food to move more slowly out of the stomach.
How does tirzepatide work?
GLP-1 and GIP hormones are incretin hormones. Your gut produces these hormones after you consume nutrients high in glucose or fat. These hormones stimulate your pancreas to release insulin. Insulin is a hormone that shuttles glucose from your bloodstream into your liver, muscles, and other body tissues, where it can be stored or used for energy.
Since tirzepatide increases insulin production, it is a very effective treatment for type 2 diabetes, a medical condition in which a person’s pancreas does not produce enough insulin or their body tissues are resistant to insulin’s effect. When insulin levels increase, it suppresses ghrelin release into circulation. This is helpful for weight loss because ghrelin stimulates hunger.1
Besides increasing insulin production, GLP-1 and GIP hormones slow stomach emptying and suppress hunger. By slowing how fast your stomach empties, tirzepatide slows the flow of nutrients from your gut into your bloodstream, which helps stabilize your blood sugar.
GLP-1 receptor agonists also affect appetite regulation in the brain. Many people who take tirzepatide explain that the medication quiets food noise. After taking tirzepatide, they think about food less and feel less hungry. Some even report that they enjoy food less. These effects make it easier to follow a reduced-calorie diet.
What are the potential benefits as a result of tirzepatide’s MOA?
Tirzepatide MOA has the potential to lead to the following beneficial effects:3,4,5
- Decreases blood pressure
- Decreases food cravings
- Decreases glucagon release from the pancreas
- Decreases liver fat
- Increases HDL (good) cholesterol
- Increases insulin release from the pancreas
- Increases insulin sensitivity
- Increases satiety
- Increases weight loss
- Lowers blood sugar
- Protects bone density
- Protects heart function
- Reduces LDL (bad) cholesterol
- Reduces triglycerides
- Slows food digestion
- Suppresses appetite
What side effects are caused by tirzepatide mechanism of action?
Side effects while taking tirzepatide include the following:6,7
- Nausea
- Diarrhea
- Decreased appetite
- Vomiting
- Constipation
- Indigestion
- Abdominal pain
- Injection site reactions
- Fatigue
- Hypersensitivity reactions
- Increased gas
- Hair loss
In most cases, the side effects were rated as mild to moderate in intensity. These side effects were more common or worsened when participants first started taking tirzepatide or when their dosage was increased. Tirzepatide is administered at a slowly increasing dose to reduce the potential for side effects.
Tirzepatide can also cause low blood sugar, especially in people with diabetes. Low blood sugar can present with the following symptoms:
- Increased sweating
- Dizziness
- Blurred vision
- Anxiety, irritability, or other mood changes
- Slurred speech
- Headaches
- Fast heartbeat
In addition to these more common side effects, tirzepatide can cause some potentially serious adverse effects, such as serious allergic reactions, thyroid cancer, and pancreatitis. If you have a personal or family history of thyroid cancer, let your doctor know before you take tirzepatide. Thyroid cancers and tumors were seen in animal trials and studies, and their relevance to humans is not fully known at this point.
How is tirzepatide administered?
Because of tirzepatide’s MOA and chemical composition, it stays in the body longer than naturally produced GLP-1 and GIP hormones. Tirzepatide is administered once a week as a subcutaneous (just under the skin) injection. The typical tirzepatide dosing schedule starts at 2.5 mg once a week for 4 weeks. The dosage is increased by 2.5 mg every 4 weeks until a maintenance dose is reached.
Tirzepatide is available only by prescription. Compounded tirzepatide is an option when the medication is not available or needs to be customized to meet an individual patient’s needs. The U.S. allows compounding pharmacies to step in and fill the gap between supply and demand if the drug is listed on the drug shortage list. Tirzepatide is currently on this list.
Understanding how tirzepatide works for weight loss is an important step toward determining whether it is an appropriate weight-loss medication option for you. To qualify for tirzepatide, patients must have a body mass index (BMI) of 30 or higher or 27 or higher with a weight-related medical condition. If you meet these criteria and are interested in tirzepatide as a weight loss treatment option, the next step is to talk with a medical provider at Invigor Medical. They will evaluate your medical history and discuss the best weight loss treatment options with you.
