Tirzepatide is a glucagon-like peptide-1 (GLP-1) receptor agonist and glucose-dependent insulinotropic polypeptide (GIP) receptor agonist approved by the FDA in 2023 for chronic weight management.
Clinical evidence shows tirzepatide can be highly effective for chronic weight loss when used long-term, especially at higher doses, though diet and exercise are still recommended for best results.
What Are the Mechanisms of Action for Tirzepatide?
By activating these two gut hormone receptors, tirzepatide mimics the effects of the incretin hormones GIP and GLP-1. This leads to several metabolic effects:
Reduces appetite and enhances satiety. Both GIP and GLP-1 activation in the brain suppress appetite. Tirzepatide causes greater reductions in appetite and food intake than GLP-1 agonists alone.
Slows gastric emptying and reduces post-meal spikes in blood glucose. GLP-1 receptor activation inhibits glucagon secretion and delays gastric emptying.
Increases insulin secretion and lowers blood glucose levels. Both GIP and GLP-1 stimulate insulin secretion in a glucose-dependent manner from pancreatic beta cells.
Promotes fat metabolism and energy expenditure. GLP-1 and GIP may increase fatty acid oxidation and thermogenesis.
Causes weight loss. In clinical trials, tirzepatide resulted in greater weight loss than other GLP-1 receptor agonists, likely due to its additional GIP receptor activation.
What Weight Loss Results Can I Expect With Tirzepatide?
Tirzepatide is a newer anti-obesity drug that has shown promising results in clinical trials for weight loss.
In a 2021 study, participants taking the highest dose of 15 mg achieved an average weight loss of 12.4 kg (27.3 lbs) after 72 weeks, with A1C reductions of 2.46%.
More recent data from 2022 indicates tirzepatide resulted in over 20% weight reduction on average (around 52 lbs) for those with obesity. Individual results can vary but significant weight loss over 15% was achieved in many participants.
Noticeable weight loss effects tend to be seen within the first 6 months. One study found 5% weight loss after 3 months and 15% after 6 months on average with tirzepatide. Weight loss continues over time, with maximum results seen at the 1 year mark.
Tirzepatide works by mimicking hormones involved in controlling hunger and fullness. This allows for reduced calorie intake and subsequent weight loss.
More research is still needed but current data suggests tirzepatide may be one of the more effective pharmacological options for weight management.
Does Tirzepatide Work Better Than Other Weight Loss Medications?
Tirzepatide appears to be more effective for weight loss than other current options when used as directed alongside a healthy lifestyle. Here is a brief comparison:
Tirzepatide (Mounjaro): A recent clinical trial found people taking tirzepatide lost an average of 22-25 lbs over 68 weeks, significantly more than other groups. However, long-term use may be needed to maintain weight loss. Individual results vary depending on factors like compliance with the treatment plan.
Semaglutide (Wegovy): When used as an injection weekly, Wegovy typically leads to 15% weight loss from baseline over 68 weeks of treatment. However, tirzepatide appears to outperform Wegovy for weight loss in head-to-head trials.
Liraglutide (Saxenda): As an injection, Saxenda typically leads to 8-10% weight loss from baseline. Tirzepatide and Wegovy both appear more effective than Saxenda based on clinical trial results.
Orlistat (Xenical): Taken as a pill with meals, Orlistat may lead to 5-10% weight loss typically when combined with lifestyle changes. It is generally considered less effective than the newer injectable options.
Available evidence suggests tirzepatide may lead to greater weight loss than other current medications for most people when used as directed long-term.
However, individual efficacy can vary significantly based on lifestyle factors and compliance with the prescribed treatment plan. A balanced diet and exercise are important for optimal and sustainable results with any approved weight loss drug.
Can I Maintain Weight Loss After Stopping Tirzepatide?
Tirzepatide helps with significant weight loss but patients may need to continue taking it long-term to maintain the loss, as weight is regained after stopping treatment. Maintaining lifestyle changes can also help prevent regaining all of the lost weight.
Studies have shown:
- Patients who took tirzepatide lost a significant amount of weight. However, some patients regained weight after stopping treatment.
- Only about 1/3 of patients were able to maintain a clinically meaningful amount of weight loss in the long-run after discontinuing other similar medications called GLP-1 receptor agonists.
To prevent regaining weight after stopping tirzepatide:
- Gradually adopt a reduced-calorie diet and increase physical activity used during medication treatment. Losing 5-10% of body weight through lifestyle changes can be maintained long-term.
- Seek behavioral counseling support to develop strategies for managing hunger, cravings and emotional eating triggers without medication.
- Consider continuing a lower dose of tirzepatide or switching to another weight loss medication under medical supervision if lifestyle changes alone are not effective.
Long-term success requires a lifelong commitment to healthy habits rather than relying on temporary drug treatment alone. Consult your healthcare provider to develop an individualized weight maintenance plan.
Are There Any Specific Health Conditions That Benefit More From Tirzepatide?
Tirzepatide has been shown to help with weight loss in several health conditions:
Type 2 diabetes
In clinical trials, tirzepatide led to significant weight loss in individuals with type 2 diabetes compared to other antidiabetic medications like insulin or sulfonylureas. It works well as an adjunct treatment or as monotherapy.
Obesity
The FDA has approved tirzepatide for chronic weight management in adults with obesity or overweight who have weight-related medical problems. In one study, people taking tirzepatide lost an average of 22.5 pounds over 68 weeks.
PCOS
Due to its weight loss effects, tirzepatide may help manage weight gain associated with PCOS which can exacerbate health issues. More research is still needed but it shows potential.
Cardiovascular disease
Weight loss with tirzepatide may help reduce cardiovascular risk factors like high blood pressure and cholesterol.
As for interactions, tirzepatide should not be taken with other GLP-1 receptor agonists. It may also interact with some medications cleared by the kidneys.
More research is still needed on breastfeeding and contraindications. Remember to consult your doctor for personalized recommendations.
Is Tirzepatide Safe for Everyone?
Tirzepatide is generally considered safe for weight loss when prescribed by a doctor, however it may not be suitable for everyone. Some key points:
- The FDA has approved tirzepatide under the brand name Zepbound for weight loss in adults without diabetes.
- Clinical trials showed significant weight loss of up to 15.7% in adults taking tirzepatide, but common side effects included nausea.
- Like other GLP-1 receptor agonists, tirzepatide carries warnings about risks of thyroid tumors in animal studies and pancreatitis. Risks should be discussed with a doctor.
- Safety and efficacy were established through clinical trials, but long term effects beyond 2 years are still unknown. Individual results may vary.
- People with a personal or family history of medullary thyroid cancer or Multiple Endocrine Neoplasia syndrome type 2 should not take tirzepatide.
As with any new drug, rare or long-term adverse reactions are possible. Consult your doctor to discuss risks and see if tirzepatide is suitable given your individual medical history.
What Are the Known Side Effects of Tirzepatide?
The most commonly reported side effects of tirzepatide include:
- Nausea
- Diarrhea
- Decreased appetite
- Vomiting
- Stomach pain
- Constipation
- Indigestion
- Tiredness
- Loss of appetite
- Swelling, redness or itching at the injection site
Who Should Not Use Tirzepatide?
Individuals should not use tirzepatide if they:
- Have a personal or family history of medullary thyroid carcinoma.
- Are allergic to tirzepatide or any ingredients in the drug.
- Have type 1 diabetes.
- Have Multiple Endocrine Neoplasia syndrome type 2 (MEN 2) or a family history of it.
- Are taking other tirzepatide-containing products or GLP-1 receptor agonists. It has not been studied with other medications.
How is Tirzepatide Administered and Dosed?
Tirzepatide is administered subcutaneously (injected under the skin) once weekly. The standard initiation dose is 2.5 mg for 4 weeks.
After 4 weeks, the dose may be increased based on treatment goals and tolerability to:
- 5 mg once weekly
- 7.5 mg once weekly
- Higher doses up to 10 mg twice weekly have been used in animal studies for carcinogenicity testing.
Can I Get Tirzepatide Without a Prescription?
While some websites claim to provide tirzepatide without a prescription, obtaining prescription drugs in this way raises safety concerns as there is no oversight on drug quality, accuracy of dosage, or management of any side effects.
It would be best to talk to your doctor about whether tirzepatide may be suitable for you, and to have them write a prescription to fill at a licensed pharmacy if appropriate.
