Retatrutide vs Tirzepatide

Head-to-head evidence comparison — which supplement is right for you?

Quick answerNo interaction data — ask a pharmacist

Retatrutide vs Tirzepatide: Tirzepatide has the stronger overall evidence (7.8 vs 5.5/10); they're alternatives for manage weight — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.

Tirzepatide Edges Ahead

Tirzepatide wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.

Retatrutide0 wins

Tirzepatide2 wins

Which is right for you? Take the 60-second quiz Open in the full comparison tool

Ret5.5

Retatrutide

Too few graded studiesLimited safety

Tir7.8

Tirzepatide

Too few graded studiesLimited safety

Evidence

Evidence Score

5.5/10

Studies: 52

Meta-analyses: 12

Level: Moderate

Evidence Score

Best7.8/10

Studies: 133

Meta-analyses: 42

Level: Strong

Research findings

Verdict

Too few graded studies

Top outcomes

Weight managementToo few graded studies40
Glucose & glycemic controlToo few graded studies27
Safety profileToo few graded studies10

Verdict

Too few graded studies

Top outcomes

Weight managementToo few graded studies80
Glycemic & metabolic controlToo few graded studies53
Heart & blood pressureToo few graded studies20

Shared outcomes (2)

Outcomes where both Retatrutide and Tirzepatide have evidence — compare verdict strength side-by-side.

Weight managementToo few graded studies40Too few graded studies80
Glycemic & metabolic controlToo few graded studies27Too few graded studies53

Dosage & timing

Recommended Dosage:

SupStack does not provide a self-directed dosing protocol for Retatrutide. A dose used in a clinical trial does not establish a safe consumer dose. Phase-2 trials used once-weekly subcutaneous injection with stepwise escalation (e.g. start 2 mg) up to 8-12 mg maintenance.

Warnings

INVESTIGATIONAL DRUG — retatrutide is NOT a dietary supplement. The first phase-3 trial (type 2 diabetes, TRANSCEND-T2D-1) has reported, but the phase-3 obesity and cardio-kidney-outcome (TRIUMPH) program is still ongoing as of 2026; long-term safety, durability and hard clinical outcomes are unknown.
The largest reported weight loss (~24%) is genuinely striking, but it rests on a single phase-2 obesity trial; the first phase-3 (a T2D trial) showed ~15% weight loss, and there is still no phase-3 obesity confirmation of the ~24% figure and no cardiovascular/renal/mortality outcome data.
Grey-market 'retatrutide' sold online despite no approval is especially risky — it is an unapproved investigational drug with no clinical oversight, no identity/purity/sterility guarantee, and no dosing standard.
GLP-1-class effects apply: dose-related gastrointestinal events, gallbladder events, a pancreatitis class concern, and lean-mass loss alongside fat loss.
Glucagon-receptor agonism produced dose-dependent heart-rate increases and can transiently affect glucose; cardiovascular consequences are not yet characterised.
Expected GLP-1-class thyroid C-cell (medullary thyroid carcinoma) warning applies pending long-term human data.

Best Time:

Once a week

Can take on empty stomach

Best Form:

Once-weekly subcutaneous injection (investigational only)

Recommended Dosage:

Once-weekly subcutaneous injection, started at 2.5 mg and escalated by 2.5 mg every 4 weeks to a maintenance dose of 5, 10, or 15 mg (per the prescribing physician and approved indication)

Warnings

PRESCRIPTION DRUG — this is an FDA-approved medication (Mounjaro / Zepbound), not a dietary supplement. Use only under medical supervision for an approved indication.
US FDA labeling includes a boxed warning about thyroid C-cell tumors: tirzepatide caused these tumors in rodents; relevance to humans is uncertain. Under the US label it is contraindicated with a personal or family history of medullary thyroid carcinoma (MTC) or MEN2. For treatment in Germany or Austria, consult the current EU product information for the exact medicine’s locally approved indications, contraindications and warnings; discuss any thyroid history with the prescriber.
Pancreatitis has been reported — discontinue and seek care for severe, persistent abdominal pain; avoid in those with a pancreatitis history.
Gallbladder disease (gallstones, cholecystitis) can occur, partly related to rapid weight loss.
Gastrointestinal adverse effects (nausea, vomiting, diarrhea, constipation) are common, especially during dose escalation.
A portion of the weight lost is lean (muscle) mass — prioritize adequate protein and resistance exercise.
FDA has warned about compounded and grey-market tirzepatide of unverified identity, purity, and dose — do not source outside a legitimate prescription.
Not for cosmetic or off-label use without a medical indication and supervision.
May reduce the efficacy of oral contraceptives via delayed gastric emptying — use a backup method when starting and after dose increases.
Benefits depend on continued use — randomized withdrawal data show substantial weight regain after stopping.

Best Time:

Any time of day

Can take on empty stomach

Best Form:

Once-weekly subcutaneous injection (Mounjaro / Zepbound)

Safety

Limited safetyTie

Drug Interactions:

Other GLP-1 / incretin drugs (severe)
Oral medications (delayed gastric emptying) (moderate)
Insulin / insulin secretagogues (sulfonylureas) (moderate)

Side Effects:

Nausea / vomitingDiarrhoea / constipationIncreased heart rate

Contraindications:

Not a dietary supplement and not an approved drug — investigational; do not self-source grey-market vials
Personal/family history of medullary thyroid carcinoma or MEN 2 (expected GLP-1-class thyroid C-cell precaution, not a product-label contraindication: this investigational drug has no label, and not every approved GLP-1 product carries the US thyroid boxed warning)

Limited safetyTie

Drug Interactions:

Oral contraceptives (moderate)
Insulin and sulfonylureas (moderate)
Oral medications generally (moderate)

Side Effects:

NauseaDiarrheaVomiting

Contraindications:

Personal or family history of medullary thyroid carcinoma (MTC) (a contraindication under the US label)
Multiple endocrine neoplasia syndrome type 2 (MEN2) (a contraindication under the US label)

Shared goals

Manage weightTirzepatide

Retatrutide68/100

Tirzepatide90/100

Manage blood sugarTirzepatide

Retatrutide58/100

Tirzepatide85/100

Metabolic healthTirzepatide

Retatrutide56/100

Tirzepatide72/100

What you'll notice

⚖️ Large weight loss (phase-2 only)positive

Progressive over 24-48 weeks

🫀 Liver-fat reduction (MASLD substudy)positive

By 24 weeks

🩸 Improved glycemic controlpositive

By 24-36 weeks

🤢 Gastrointestinal adverse eventstrade-off

Especially during dose escalation

🩸 Strong glycemic controlpositive

Weeks to months

⚖️ Large weight losspositive

Months (dose-escalated over ~20 weeks)

😴 Reduced sleep-apnea severitypositive

Weeks to months

🤢 GI side effects (common)negative

Mostly during titration

Key studies

Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial.

N Engl J Med (2023) · Rct · n=338

Phase-2, double-blind, randomized, placebo-controlled trial in 338 adults with obesity (or overweight + a weight-related condition), once-weekly subcutaneous retatrutide 1-12 mg vs placebo for 48 weeks

Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USA.

Lancet (2023) · Rct · n=281

Phase-2, double-blind, double-dummy, placebo- and active-comparator (1.5 mg dulaglutide)-controlled trial in 281 adults with type 2 diabetes, once-weekly retatrutide 0.5-12 mg over 36 weeks

Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial.

Nat Med (2024) · Rct · n=98

Phase-2a, randomized, double-blind, placebo-controlled MASLD substudy (n=98) of the obesity trial, in participants with ≥10% liver fat, once-weekly retatrutide 1-12 mg vs placebo

All Retatrutide studies

Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes.

N Engl J Med (2021) · Rct · n=1879

Open-label 40-week phase-3 head-to-head RCT (SURPASS-2) in 1879 patients with type 2 diabetes, tirzepatide 5/10/15 mg vs semaglutide 1 mg

Tirzepatide Once Weekly for the Treatment of Obesity.

N Engl J Med (2022) · Rct · n=2539

72-week phase-3 double-blind RCT (SURMOUNT-1) in 2539 adults with obesity (without diabetes), tirzepatide 5/10/15 mg vs placebo

Tirzepatide as Compared with Semaglutide for the Treatment of Obesity.

N Engl J Med (2025) · Rct · n=751

Phase-3b open-label head-to-head RCT (SURMOUNT-5) in 751 adults with obesity but without diabetes, max-tolerated tirzepatide vs max-tolerated semaglutide

All Tirzepatide studies

Frequently asked questions

Is Retatrutide better than Tirzepatide?

Tirzepatide has a higher evidence score (7.8/10 vs 5.5/10) and wins in 2 of 3 categories.

Is Retatrutide or Tirzepatide better for manage weight?

For manage weight, Tirzepatide has a higher relevance score (90 vs 68).

Can I take Retatrutide and Tirzepatide together?

No documented interaction was found in the data searched. This does not establish that this exact combination is safe.

Related comparisons

Retatrutide vs Whey Protein Retatrutide vs Semaglutide Liraglutide vs Retatrutide Semaglutide vs Tirzepatide Liraglutide vs Tirzepatide Thiamine vs Tirzepatide

Still deciding between Retatrutide and Tirzepatide?

The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.

Get your personalised pick Retatrutide details Tirzepatide details

Warnings

INVESTIGATIONAL DRUG — retatrutide is NOT a dietary supplement. The first phase-3 trial (type 2 diabetes, TRANSCEND-T2D-1) has reported, but the phase-3 obesity and cardio-kidney-outcome (TRIUMPH) program is still ongoing as of 2026; long-term safety, durability and hard clinical outcomes are unknown.

The largest reported weight loss (~24%) is genuinely striking, but it rests on a single phase-2 obesity trial; the first phase-3 (a T2D trial) showed ~15% weight loss, and there is still no phase-3 obesity confirmation of the ~24% figure and no cardiovascular/renal/mortality outcome data.

Grey-market 'retatrutide' sold online despite no approval is especially risky — it is an unapproved investigational drug with no clinical oversight, no identity/purity/sterility guarantee, and no dosing standard.

GLP-1-class effects apply: dose-related gastrointestinal events, gallbladder events, a pancreatitis class concern, and lean-mass loss alongside fat loss.

Glucagon-receptor agonism produced dose-dependent heart-rate increases and can transiently affect glucose; cardiovascular consequences are not yet characterised.

Expected GLP-1-class thyroid C-cell (medullary thyroid carcinoma) warning applies pending long-term human data.

Warnings

PRESCRIPTION DRUG — this is an FDA-approved medication (Mounjaro / Zepbound), not a dietary supplement. Use only under medical supervision for an approved indication.

US FDA labeling includes a boxed warning about thyroid C-cell tumors: tirzepatide caused these tumors in rodents; relevance to humans is uncertain. Under the US label it is contraindicated with a personal or family history of medullary thyroid carcinoma (MTC) or MEN2. For treatment in Germany or Austria, consult the current EU product information for the exact medicine’s locally approved indications, contraindications and warnings; discuss any thyroid history with the prescriber.

Pancreatitis has been reported — discontinue and seek care for severe, persistent abdominal pain; avoid in those with a pancreatitis history.

Gallbladder disease (gallstones, cholecystitis) can occur, partly related to rapid weight loss.

Gastrointestinal adverse effects (nausea, vomiting, diarrhea, constipation) are common, especially during dose escalation.

A portion of the weight lost is lean (muscle) mass — prioritize adequate protein and resistance exercise.

FDA has warned about compounded and grey-market tirzepatide of unverified identity, purity, and dose — do not source outside a legitimate prescription.

Not for cosmetic or off-label use without a medical indication and supervision.

May reduce the efficacy of oral contraceptives via delayed gastric emptying — use a backup method when starting and after dose increases.

Benefits depend on continued use — randomized withdrawal data show substantial weight regain after stopping.

Frequently asked questions

Is Retatrutide better than Tirzepatide?

Tirzepatide has a higher evidence score (7.8/10 vs 5.5/10) and wins in 2 of 3 categories.

Is Retatrutide or Tirzepatide better for manage weight?

For manage weight, Tirzepatide has a higher relevance score (90 vs 68).

Can I take Retatrutide and Tirzepatide together?

No documented interaction was found in the data searched. This does not establish that this exact combination is safe.