Retatrutide vs MK-677

A comprehensive, data-driven comparison of Retatrutide (LY3437943) and MK-677 (Ibutamoren). Compare efficacy, side effects, costs, FDA approval status, and clinical evidence to make an informed decision.

Retatrutide
Phase 3 (NDA expected late 2026)
Obesity and weight management
Evidence
High
Avg. Weight Loss28.7%
Monthly Cost$1,200 - $1,500/mo
DosingWeekly
ManufacturerEli Lilly
MK-677
Phase 2
Growth hormone optimization and muscle growth
Evidence
Moderate
Monthly Cost$50 - $100/mo
DosingDaily

Side-by-Side Comparison

PropertyRetatrutide
LY3437943
MK-677
Ibutamoren, Nutrobal
FDA Status
Phase 3 (NDA expected late 2026)
Phase 2
Category
Weight Loss
Growth Hormone
Primary Use
Obesity and weight management
Growth hormone optimization and muscle growth
Weight Loss %
28.7%
N/A
Monthly Cost
$1,200 - $1,500/mo
$50 - $100/mo
Administration
Subcutaneous injection
Oral
Typical Dose
12mg weekly (dose escalated from 2mg)
10-25mg daily
Frequency
Weekly
Daily
Mechanism

Triple agonist targeting GIP, GLP-1, and glucagon receptors to enhance insulin secretion, reduce appetite, and increase energy expenditure

Oral growth hormone secretagogue that mimics ghrelin to stimulate GH and IGF-1 release

Common Side Effects
  • Nausea
  • Diarrhea
  • Vomiting
  • Constipation
  • +3 more
  • Increased appetite
  • Water retention
  • Fatigue
  • Muscle pain
  • +1 more
Serious Side Effects
  • Pancreatitis
  • Gallbladder disease
  • Severe gastrointestinal reactions
  • Hypoglycemia (if combined with insulin)
  • Insulin resistance
  • Elevated prolactin
  • Potential impact on cancer risk
Evidence Quality
High
Moderate
Clinical Trial Phase
Phase 3
Phase 2

Key Differences

  • 1Retatrutide has clinical weight loss data (28.7%), while MK-677 is not primarily indicated for weight loss.
  • 2MK-677 is generally more affordable ($50 - $100/mo) compared to Retatrutide ($1,200 - $1,500/mo).
  • 3Retatrutide is administered via subcutaneous injection, while MK-677 uses oral.
  • 4Retatrutide is dosed weekly, while MK-677 is daily.
  • 5Retatrutide has high-quality evidence, while MK-677 has moderate-quality evidence.
  • 6They belong to different categories: Retatrutide (Weight Loss) vs MK-677 (Growth Hormone).

Which Is Better For...

MK

MK-677

More budget-friendly option with lower monthly costs

RE

Retatrutide

More convenient dosing schedule (weekly)

MK

MK-677

Fewer commonly reported side effects

RE

Retatrutide

Stronger clinical evidence base to support its use

Cost Comparison

PeptideMonthly Cost RangeFDA StatusManufacturer
Retatrutide$1,200 - $1,500/mo
Phase 3 (NDA expected late 2026)
Eli Lilly
MK-677$50 - $100/mo
Phase 2
Various research labs

Prices are estimated monthly costs and may vary based on pharmacy, insurance coverage, and manufacturer assistance programs. Costs for non-FDA-approved peptides reflect research compound pricing.

Frequently Asked Questions

What is the main difference between Retatrutide and MK-677?

Retatrutide works via Triple agonist targeting GIP, GLP-1, and glucagon receptors to enhance insulin secretion,. MK-677 works via Oral growth hormone secretagogue that mimics ghrelin to stimulate GH and IGF-1. They differ in FDA approval status, efficacy data, and cost.

Which is more effective for weight loss, Retatrutide or MK-677?

Retatrutide has demonstrated 28.7% average weight loss in clinical trials. MK-677 is not primarily used for weight loss.

How much does Retatrutide cost compared to MK-677?

Retatrutide typically costs $1,200 - $1,500/mo, while MK-677 costs $50 - $100/mo. Prices may vary by pharmacy, insurance coverage, and manufacturer programs.

Are Retatrutide and MK-677 FDA approved?

Retatrutide is not FDA-approved (Phase 3 (NDA expected late 2026)). MK-677 is not FDA-approved (Phase 2). FDA approval indicates the treatment has met rigorous safety and efficacy standards.

What are the side effects of Retatrutide vs MK-677?

Common side effects of Retatrutide include Nausea, Diarrhea, Vomiting. Common side effects of MK-677 include Increased appetite, Water retention, Fatigue. Always consult a healthcare provider about potential side effects.

Can I switch from Retatrutide to MK-677?

Switching between peptide therapies should only be done under the guidance of a qualified healthcare provider. They can evaluate your medical history, current response, and determine the safest transition protocol.

Learn More

Retatrutide Full Profile
Obesity and weight management

Retatrutide is a novel triple-receptor agonist developed by Eli Lilly currently in Phase 3 clinical trials. It has demonstrated unprecedented weight loss results, with patients losing an average of 28...

View Full Retatrutide Guide
MK-677 Full Profile
Growth hormone optimization and muscle growth

MK-677 (Ibutamoren) is an orally-active growth hormone secretagogue that mimics the action of ghrelin. Unlike peptide injections, it is taken orally and has a long half-life allowing once-daily dosing...

View Full MK-677 Guide

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Medical Disclaimer

The information provided on this page is for educational and informational purposes only and does not constitute medical advice. This comparison between Retatrutide and MK-677 should not be used as a substitute for professional medical guidance. Always consult a qualified healthcare provider before starting, stopping, or modifying any peptide therapy. Clinical data cited may be from ongoing trials and is subject to change. Individual results may vary significantly. PeptideVS does not endorse, recommend, or promote the use of any specific peptide for medical treatment.