Introduction to Tirzepatide
Tirzepatide is an exciting new medication that has shown promising results for treating type 2 diabetes and obesity. It is not yet FDA-approved but is currently undergoing clinical trials. Tirzepatide is a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist. It helps control blood sugar levels while also suppressing appetite to aid in weight loss.
Tirzepatide works by mimicking the effects of two natural hormones in the body - GIP and GLP-1. These hormones are released from the intestines after eating and help stimulate the release of insulin, which lowers blood sugar. They also send signals of fullness to the brain to reduce appetite. Tirzepatide activates receptors for both GIP and GLP-1, leading to improved blood sugar control and weight loss.
Clinical Trial Results
In phase 3 clinical trials, tirzepatide has been shown to lower A1C (a measure of blood sugar control over 3 months) by up to 2.37% compared to placebo. It also led to an average weight loss of 12.4 kg (over 27 pounds) in just 40 weeks at the highest studied dose of 15mg. These results suggest that tirzepatide may be more effective than other GLP-1 drugs like semaglutide (Ozempic) both for diabetes and for obesity.
The most common side effects were mild-to-moderate gastrointestinal problems like nausea, vomiting, and diarrhea. These adverse effects decreased over time with continued tirzepatide use. No severe hypoglycemia (very low blood sugar) was seen in clinical trials.
Tirzepatide + Vitamin B6
One strategy some people are trying to manage tirzepatide's gastrointestinal side effects is adding vitamin B6. Vitamin B6 is known to help relieve nausea and vomiting in conditions like morning sickness during pregnancy. Some early anecdotal reports suggest combining tirzepatide with daily B6 may help reduce GI issues.
There is no clinical evidence yet on taking vitamin B6 with tirzepatide. Vitamin B6 is generally safe at recommended daily doses of 1.3-1.7mg. High doses over 100mg long-term can possibly cause nerve damage. Most multivitamins contain around 2mg B6.
Talk to your doctor before starting any new supplements like vitamin B6. Be sure to report any persistent GI side effects while taking tirzepatide as your dose may need adjusting. Staying hydrated and taking tirzepatide with food can also help minimize stomach issues.
How Does Tirzepatide Work?
To understand how tirzepatide works, it helps to first understand the normal role of GIP and GLP-1 hormones in the body.
GIP and GLP-1 are secreted from intestinal cells after eating, particularly when there are nutrients like glucose, fat or amino acids present. They bind to and activate GIP and GLP-1 receptors located on various cells throughout the body:
- Pancreatic beta cells - Stimulates insulin release
- Pancreatic alpha cells - Inhibits glucagon release
- Stomach and intestines - Slows digestion and suppresses appetite
- Brain - Activates feelings of fullness and satiety
Together, the actions of GIP and GLP-1 lower blood sugar, inhibit glucagon secretion, promote satiety and lead to weight loss. However, native GIP and GLP-1 get rapidly broken down by an enzyme called DPP-4 within minutes of secretion.
Tirzepatide is a synthetic dual GIP and GLP-1 receptor agonist. This means it activates both the GIP and GLP-1 receptors in the body. The key advantages of tirzepatide are:
- Resistant to DPP-4 breakdown so stays active longer
- Balanced co-activation of the GIP and GLP-1 pathways
- Once-weekly dosing for patient convenience
By mimicking and enhancing the effects of GIP and GLP-1 simultaneously, tirzepatide can lower HbA1c and promote weight loss more effectively than selective GLP-1 drugs like semaglutide.
Blood Sugar Control
Activation of GIP and GLP-1 receptors by tirzepatide enhances glucose-dependent insulin release from pancreatic beta cells. This means more insulin is secreted only when blood glucose levels are elevated, lowering blood sugar after meals.
Tirzepatide also suppresses the secretion of glucagon from pancreatic alpha cells. Glucagon is a hormone that raises blood sugar, so inhibiting it also helps control glucose levels.
These dual effects on insulin and glucagon secretion allow tirzepatide to effectively improve glycemic control in patients with type 2 diabetes while having a low risk of hypoglycemia.
Weight Loss
Tirzepatide promotes weight loss through reducing appetite and slowing gastric emptying:
- Appetite suppression - Activation of GLP-1 and GIP receptors in the brain increases feelings of fullness after eating and reduces appetite drive.
- Slower gastric emptying - Tirzepatide slows stomach emptying and gut motility, which helps promote satiety and delays the next meal.
The combination of appetite and gastric effects enables sustained weight loss with tirzepatide treatment over time without the need for restrictive dieting.
Access to Tirzepatide
Tirzepatide is currently under development by pharmaceutical company Eli Lilly under the brand names Mounjaro and Zepbound. It has not yet been approved by the FDA for treating type 2 diabetes or obesity.
Once approved, tirzepatide will likely be available by prescription only. It will be administered as a once-weekly subcutaneous injection, similarly to other GLP-1 drugs like Ozempic and Wegovy.
The expected costs and insurance coverage for tirzepatide are not yet known. It will likely be an expensive medication given its novel dual mechanism of action. Many insurance plans do cover other GLP-1 drugs with prior authorization.
Compounded Tirzepatide
Some compounding pharmacies have started offering compounded versions of tirzepatide prior to FDA approval. Compounded tirzepatide is typically much cheaper than the approved pharmaceutical version will be.
However, there are risks associated with using compounded tirzepatide:
- Quality and purity cannot be guaranteed
- Dosing and potency may not be accurate
- Lack of rigorous testing for side effects
- Legality is questionable
The FDA advises against using compounded versions of investigational drugs like tirzepatide outside of clinical trials. While compounded tirzepatide is appealing for its lower cost, it does come with potentially serious health risks.
Off-Label Semaglutide Use
Since tirzepatide is not yet approved, some people are opting to use the approved GLP-1 drug semaglutide (Ozempic, Wegovy) off-label instead for weight loss. This is also driven by the high cost and limited coverage of semaglutide.
While semaglutide is structurally related to tirzepatide, there are drawbacks to off-label use:
- Only activates GLP-1 pathway, not dual like tirzepatide
- Less effective for weight loss than tirzepatide in trials
- Risk of side effects like pancreatitis at high doses
- Needle-free oral semaglutide formulations also lack evidence for safety and efficacy
FAQs
What are the main effects of tirzepatide?
Tirzepatide lowers blood sugar, suppresses appetite, and slows stomach emptying. Together these effects make it effective for treating type 2 diabetes and obesity.
How much weight can you lose on tirzepatide?
In clinical trials, people lost an average of 12.4 kg (27 pounds) while taking tirzepatide for 40 weeks at the highest dose studied.
When will tirzepatide be FDA approved?
Tirzepatide is still undergoing phase 3 clinical trials. Approval timelines depend on the results and the FDA review process. It likely won't be approved until at least 2023.
What are the risks of compounded tirzepatide?
Compounded tirzepatide has risks like imprecise dosing, unknown side effects, questionable purity and legality issues. The FDA recommends against using compounded versions.
Can you take vitamin B6 with tirzepatide?
Some people take vitamin B6 to try to reduce tirzepatide's GI side effects. There's no evidence yet on safety or effectiveness. Talk to your doctor before starting vitamin B6.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.
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