Which GLP Is Right for You? Comparing Tirzepatide, Mazdutide, and Retatrutide

Educational content only — not medical advice. These medicines have important risks and are not appropriate for everyone. Decisions should be made with a licensed clinician who can review your health history, medications, and goals. Retatrutide is investigational (not FDA-approved), and mazdutide is approved in China but not broadly approved everywhere.

GLP-1–based medications have reshaped how clinicians treat obesity and metabolic disease. But the landscape has moved beyond “GLP-1 only” into a new era of multi-receptor incretin therapies—compounds that activate more than one hormone receptor to influence appetite, satiety, glucose control, and energy balance.

Three of the most discussed options today are:

Tirzepatide (dual agonist: GIP + GLP-1) — FDA-approved for type 2 diabetes (Mounjaro) and chronic weight management (Zepbound).
Mazdutide (IBI362 / LY3305677) (dual agonist: GLP-1 + glucagon) — approved by China’s NMPA for chronic weight management (and later also for glycemic control in adults with type 2 diabetes, per company and trade reporting).
Retatrutide (LY3437943) (triple agonist: GIP + GLP-1 + glucagon) — investigational; early clinical trial results are strong, but it is still in development.

This article compares how they work, what clinical trials show, and which types of patients may generally be considered better candidates—in a safe, non-prescriptive way.

Quick definitions: What “GLP-1,” “GIP,” and “glucagon” mean

These therapies target hormone signals involved in appetite and metabolism:

GLP-1 receptor activation: increases satiety, slows gastric emptying, improves glucose control (in diabetes), and reduces appetite.
GIP receptor activation: complements GLP-1 effects and may enhance weight loss and glycemic effects in some patients (exact mechanisms are complex).
Glucagon receptor activation: can increase energy expenditure and influence fat metabolism; paired with GLP-1 to temper appetite and glucose effects.

So the “stack” matters:

Tirzepatide = GLP-1 + GIP
Mazdutide = GLP-1 + glucagon
Retatrutide = GLP-1 + GIP + glucagon

That extra receptor activity is one reason the newer agents are being studied so aggressively.

Feature	Tirzepatide	Mazdutide	Retatrutide
Receptor targets	GIP + GLP-1	GLP-1 + glucagon	GIP + GLP-1 + glucagon
Approval status	FDA-approved (T2D, weight management) (Lilly Investor Relations)	Approved in China (weight management; later diabetes indication reported) (PR Newswire)	Investigational; in clinical trials (ClinicalTrials)
Landmark published obesity trial	SURMOUNT-1 (NEJM 2022) (New England Journal of Medicine)	GLORY-1 (NEJM 2025) (New England Journal of Medicine)	Phase 2 trial (NEJM 2023) (PubMed)
Typical theme	Very strong weight + glycemic effects	Weight loss + potential metabolic/liver benefits in studies	Highest early efficacy signals; still being validated
Common side effects	GI effects (nausea, diarrhea, vomiting), others	GI effects (nausea/diarrhea), others	GI effects (dose-dependent), others

Tirzepatide: the established “two-incretin” option

What it is

Tirzepatide is a dual GIP/GLP-1 receptor agonist. It’s approved by the FDA for:

Type 2 diabetes (Mounjaro)
Chronic weight management (Zepbound)

What the evidence shows (high level)

The best-known obesity trial is SURMOUNT-1, a 72-week study in adults with obesity/overweight without diabetes. It demonstrated substantial and sustained weight reduction compared with placebo.

Tirzepatide has also shown meaningful improvements in cardiometabolic markers (blood pressure, lipids, glycemic measures) across multiple studies and analyses, and has a growing evidence base because it is already widely prescribed for approved indications.

Safety and tolerability considerations

Like other incretin therapies, tirzepatide commonly causes gastrointestinal side effects (nausea, diarrhea, vomiting). The FDA labeling also includes important warnings and contraindications (for example, class warnings related to thyroid C-cell tumors and other risks). Always defer to the official label and a clinician’s judgment.

Who tirzepatide may be “better for” (general considerations)

In clinician practice, tirzepatide is often considered when someone has:

Type 2 diabetes + weight goals

Because it has FDA approval for type 2 diabetes and strong effects on glucose control and body weight.

A need for a well-characterized, widely studied option

It has large, published trials and post-approval experience relative to investigational molecules.

Preference for an option with U.S. FDA approval for weight management

Zepbound’s FDA approval matters for safety oversight, prescribing, and legitimate supply chains.

Where it may be less ideal (again, general):

If a patient has significant GI intolerance to incretin therapies.
If contraindications apply (must be screened clinically).
If access/coverage issues prevent consistent therapy (continuity matters).

Mazdutide: GLP-1 plus glucagon — a different metabolic angle

What it is

Mazdutide (IBI362 / LY3305677) is a dual agonist of GLP-1 and the glucagon receptor, developed with Innovent and Eli Lilly collaboration.

Approval status and where it’s used

Mazdutide has received China NMPA approval for chronic weight management (announced June 27, 2025).
Industry reporting also describes additional China approvals/indications (including type 2 diabetes) around 2025.

What the evidence shows

The GLORY-1 Phase 3 trial in Chinese adults with overweight/obesity was published in NEJM (2025). A company release summarizing the NEJM publication reported:

At Week 32, mean percent body-weight change (efficacy estimand) of approximately −10.97% (4 mg) and −13.38% (6 mg) vs ~−0.24% placebo.
At Week 48, about −12.05% (4 mg) and −14.84% (6 mg) vs −0.47% placebo (efficacy estimand).
High proportions achieved ≥5% weight reduction (reported >75% in active arms) vs ~10% placebo at week 32.

Earlier phase 2 work (published in Nature Communications) also showed robust weight reduction and a safety profile consistent with incretin therapy (GI side effects commonly reported).

Who tirzepatide may be “better for” (general considerations)

In clinician practice, tirzepatide is often considered when someone has:

Type 2 diabetes + weight goals

Because it has FDA approval for type 2 diabetes and strong effects on glucose control and body weight.

A need for a well-characterized, widely studied option

It has large, published trials and post-approval experience relative to investigational molecules.

Preference for an option with U.S. FDA approval for weight management

Zepbound’s FDA approval matters for safety oversight, prescribing, and legitimate supply chains.

Where it may be less ideal (again, general):

If a patient has significant GI intolerance to incretin therapies.
If contraindications apply (must be screened clinically).
If access/coverage issues prevent consistent therapy (continuity matters).

Safety and tolerability considerations

Across studies, the most commonly reported adverse events are gastrointestinal and typically mild to moderate. Discontinuation rates due to adverse events in the NEJM trial summaries appear relatively low, but individual tolerance varies.
Because mazdutide has glucagon receptor activity, clinicians and researchers watch metabolic parameters closely (heart rate, liver markers, etc.). The exact risk/benefit balance can differ by patient.

Who mazdutide may be “better for” (general considerations)

Patients where clinicians are interested in GLP-1 + glucagon dynamics
The glucagon receptor component is a distinct approach that may influence fat metabolism and metabolic markers in some studies.
Regions where it’s approved and clinically supported
In China, the approval creates a regulated pathway.
Research focus on obesity plus metabolic comorbidities
Some reported outcomes include improvements in lipids, liver enzymes, and other cardiometabolic markers in trial populations (important: outcomes differ by study design and population).

Where it may be less ideal:

If someone is outside jurisdictions where it’s approved/accessible through legitimate channels.
If a clinician prefers the breadth of evidence and real-world experience available for FDA-approved therapies in their region.

Retatrutide: the investigational “triple agonist” with big early numbers

What it is

Retatrutide (LY3437943) is a triple hormone receptor agonist targeting GIP + GLP-1 + glucagon.

Approval status: still in trials

Retatrutide is investigational and in clinical trials. ClinicalTrials.gov lists multiple studies evaluating efficacy and safety.

What the evidence shows (what we can responsibly say)

A Phase 2 trial published in NEJM (2023) reported large, dose-dependent reductions in body weight at 24 and 48 weeks, with the highest dose arms showing the largest average reductions.
These results are one reason retatrutide is often discussed as “next generation.” But it’s crucial to treat Phase 2 results as promising, not final—Phase 3 trials exist to confirm durability, safety, and real-world tolerability at scale.

Safety and tolerability considerations

Retatrutide’s side effects in Phase 2 looked similar in category to other incretin-based therapies (often GI), but dose intensity and the added glucagon receptor activity make careful Phase 3 validation especially important.

Who retatrutide may be “better for” (general considerations)

Because it is not widely approved, retatrutide is not something people should be “choosing” in routine care yet. However, in a research/clinical-trial context, it may be relevant for:

Clinical trial participants

People who meet inclusion criteria and are willing to participate under medical supervision.

Future candidates needing maximal efficacy (pending Phase 3 confirmation)

If Phase 3 confirms Phase 2 results with an acceptable safety profile, retatrutide could become a top-tier option for significant weight reduction—but this is not established yet.

Important safety note about sourcing: Regulators have warned about online vendors selling unapproved GLP-1 drugs and experimental compounds, often using “research use only” labels while marketing for human use.
In plain terms: don’t buy retatrutide (or any prescription GLP-1) from unlicensed online sellers.

Which one is better?

There isn’t a single “best GLP” for everyone. A safer and more accurate way to think about it is:

Best for what goal, in what medical context, with what risk tolerance, and with what legal/regulated access?

Below are common decision factors clinicians consider (again: general education only).

How clinicians typically match therapy to “types of patients” (non-prescriptive)

1) If type 2 diabetes control is the priority

Tirzepatide has FDA approval and strong outcomes for glycemic control plus weight reduction in adults with type 2 diabetes.

Mazdutide has been studied for diabetes and has reported China approvals/indications; relevance depends on location and clinical availability.

Retatrutide remains investigational.

Why this matters:

diabetes management requires consistent monitoring, interaction checks, and regulatory-grade supply.

2) If maximum average weight reduction is the top objective

In head-to-head concept, not direct trial comparisons, early signals suggest:
Retatrutide Phase 2 showed very large average weight reductions at 48 weeks in high-dose arms.
Tirzepatide SURMOUNT-1 also showed large reductions over 72 weeks and has FDA-approved formulations for weight management.
Mazdutide GLORY-1 showed clinically meaningful reductions and strong responder rates (particularly at 6 mg).

But: Trials differ in duration, population, endpoints, and estimands—so don’t “rank” drugs solely from headline percentages.

3) If tolerability and day-to-day adherence is the challenge

What it is

Many people stop incretin drugs due to GI side effects. For these patients, clinicians may focus on:

slower titration strategies (within approved labeling),
nausea management,
and selecting therapies where the patient can stay consistent.

Because individual tolerance varies, “best” often means the one you can stay on safely.

4) If someone has significant cardiometabolic comorbidities

Clinicians will weigh:

blood pressure effects,
lipid changes,
glycemic markers,
kidney status,
and other medications.

Tirzepatide and mazdutide trials report improvements in multiple metabolic markers in studied populations.

5) If legality, supply chain, and legitimacy are concerns (they should be)

This is the most overlooked factor online.

Tirzepatide has legitimate pharmacy supply for FDA-approved uses.
Mazdutide has regulated access where approved (e.g., China).
Retatrutide should be accessed only via legitimate clinical trials until approved.

And regulators have explicitly warned that online sellers marketing “research use only” GLP-1s for human use are a compliance and safety risk.

A practical “decision framework” (talk to your clinician with this)

If you want a simple way to think about “which GLP is right,” bring these questions to a medical appointment:

What’s my primary goal? (glucose control, weight, fatty liver markers, appetite control, etc.)
What’s my medical risk profile? (GI history, gallbladder disease, pancreatitis history, thyroid cancer family history, kidney status, etc.)
What medications am I on that might interact or require monitoring?
What options are legal and regulated where I live?
What can I realistically access and stay consistent with?

FAQs

Still have questions? We’re here to help!

Is tirzepatide a GLP-1?

It’s commonly grouped with GLP-1s, but pharmacologically it’s a dual incretin agonist (GIP + GLP-1).

Is mazdutide the same as semaglutide?

No. Semaglutide is a GLP-1 receptor agonist. Mazdutide targets GLP-1 + glucagon receptors.

Is retatrutide available now?

Retatrutide is investigational and listed in ongoing clinical trials. It is not broadly approved for prescribing.

Why do some people say retatrutide is “stronger”?

Because Phase 2 NEJM results showed very large average weight reduction in higher-dose arms at 48 weeks. Phase 3 trials must confirm safety and durability.

Can I buy these online without a prescription?

For prescription medicines (like FDA-approved tirzepatide products), buying from unlicensed sellers is risky and may be illegal. Regulators have issued warnings about unapproved GLP-1 products marketed online using “research use only” disclaimers.