If you have followed weight loss news lately, you have seen the headlines: a new injection called retatrutide has posted large average weight loss numbers in clinical trials. So how does retatrutide vs tirzepatide actually compare, and can you get it? Here is the short answer. Retatrutide is investigational. It is not FDA-approved, and right now it is available only through registered clinical trials. If you live in Miami or near our Coral Gables location and you want to start medical weight loss now, tirzepatide is an FDA-approved option a provider can evaluate you for today. This guide explains how the two drugs work, what the research shows, and what you can do next.
What Is Retatrutide?
Retatrutide is an investigational once-weekly injection developed by Eli Lilly. What makes it different is that it acts on three hormone receptors instead of one or two. That is why you will often see it called a triple agonist.
- GLP-1: helps regulate appetite and supports the feeling of fullness after you eat.
- GIP: supports your body’s insulin response after meals.
- Glucagon: is thought to influence energy use and how your body metabolizes fat.
The idea behind combining all three is to address appetite, blood sugar, and energy expenditure at the same time. Whether that translates into a meaningful advantage for you as a patient is the question the research is still answering.
How Tirzepatide Works, and Where Retatrutide vs Tirzepatide Differ
Tirzepatide is a dual agonist. It acts on two of the same receptors, GIP and GLP-1, but not glucagon. It is FDA-approved for type 2 diabetes and, since 2023, for chronic weight management in adults with obesity, or with overweight and at least one weight-related condition. Both drugs belong to a broader family of peptide-based medications. If you want to understand how peptide treatment works in practice, our guide to how peptide therapy works walks through the process.
The practical difference for you today is less about receptors and more about access. Tirzepatide has completed the FDA review process, has published prescribing information, and can be prescribed by a licensed provider when it fits your health history. Retatrutide has not finished that process, so its long-term safety profile, approved doses, and labeling do not exist yet.
Here is how the two compare side by side:
| Retatrutide | Tirzepatide | |
|---|---|---|
| Receptors | GLP-1, GIP, and glucagon (triple agonist) | GLP-1 and GIP (dual agonist) |
| FDA status | Investigational, not FDA-approved | FDA-approved for chronic weight management and type 2 diabetes |
| Dosing frequency | Once weekly in trials | Once weekly |
| How you get it | Clinical trial enrollment only | Prescription from a licensed provider, if appropriate |
Retatrutide Side Effects and Safety Signals
The most common retatrutide side effects reported in trials were gastrointestinal: nausea, diarrhea, constipation, and vomiting. Most were described as mild to moderate and resolved during treatment. Side effects rose with dose, and discontinuation because of side effects was notable at the highest dose. In TRIUMPH-1, 11.3 percent of participants on the 12 mg dose stopped for that reason, compared with 4.9 percent on placebo.
Long-term cardiovascular benefit has not been established. In TRIUMPH-3, the major cardiovascular event results did not reach statistical significance.
If you have never taken a medication in this class, here is what GI side effects tend to look like in practice. They often show up when you start or increase a dose. They can include feeling full quickly, mild nausea after larger meals, or changes in digestion. Providers typically manage this with gradual dose increases, smaller meals, and hydration, and they adjust the plan if symptoms do not settle.
Is Retatrutide FDA-Approved?
No. As of October 22, 2026, retatrutide is not FDA-approved for any use. Eli Lilly has said it plans to submit an application to the FDA in the first quarter of 2027, and FDA review takes time after a submission. That means retatrutide is available only through registered clinical trials.
You may see products sold online labeled as retatrutide or as research peptides. These are not approved drugs. Their quality, purity, and dosing have not been verified, and they should not be used. If a seller offers you retatrutide outside of a clinical trial, treat that as a warning sign.
What You Can Do Now: Starting Medical Weight Loss With a Provider
You do not have to wait for a future drug to take a medically guided step today. At The Wellness Lab, medical weight loss starts with a conversation and a clear picture of your health. Here is what the process looks like:
- Consultation: a virtual weight loss consultation with a nurse practitioner to review your history and goals.
- Baseline labs: HbA1c, a comprehensive metabolic panel, and hormone and thyroid panels. Our hormone and metabolic panel covers much of this ground.
- FDA-approved options: if appropriate after your consultation, your provider may discuss an FDA-approved GLP-1 medication such as tirzepatide or semaglutide.
- Supplement plan and lifestyle guidance: support for nutrition, movement, and habits that fit your routine.
- Follow-up: regular check-ins so your provider can track how you are responding and adjust your plan.
Why start with labs? Your baseline numbers help your provider understand how your blood sugar, metabolism, hormones, and thyroid may be affecting your weight. They also give you a starting point to measure progress against, so the conversation at each follow-up is about your data, not guesswork.
Every plan is built around your labs and your history, and not everyone is a candidate for medication. Your provider will tell you honestly what fits.
Is retatrutide FDA-approved?
No. As of October 22, 2026, retatrutide is investigational and not FDA-approved. It is available only through registered clinical trials.
Is retatrutide stronger than tirzepatide?
That cannot be settled yet. Retatrutide’s trial averages are high, but no completed head-to-head trial has compared the two drugs directly, and trial populations differ.
Can I get retatrutide in Miami?
Only through a registered clinical trial. The Wellness Lab does not prescribe or supply retatrutide.
What are the side effects of retatrutide?
In trials, the most common side effects were gastrointestinal, including nausea, diarrhea, constipation, and vomiting. They were more frequent at higher doses.
If I start tirzepatide now, could I switch to retatrutide later?
That would be a decision for your provider, and only if retatrutide is approved in the future. Starting an FDA-approved option now does not lock you out of future conversations about your care.
Book a lab consultation
Peptide therapy starts with bloodwork and a conversation, not with a prescription.
Book a lab consultation at our Coral Gables location and we will tell you honestly whether this is the right direction for you.
Adina Arce, MSN, APRN
