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📖Complete Guide✅Updated 2026🔬Evidence-Based

Retatrutide Guide

Eli Lilly

Complete guide to Retatrutide (nicknamed "Reta" by the GLP-1 community) — the first triple agonist (GLP-1/GIP/Glucagon) showing up to 28.7% weight loss.

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Avg Weight Loss
28.7%
At the 12mg dose, participants lost an average of 28.7% of their body weight (approx. 71.2 lbs) over 68 weeks. This significantly outperforms Phase 2
Pain Reduction
75%
Retatrutide reduced WOMAC pain scores by approximately 75% (4.5 points), offering substantial relief for osteoarthritis patients. 1 in 8 patients were
High Response
58.6%
Dashboard
Your complete health overview in one place
🔥
14-day streak
Logged 18 of 18 scheduled shots
Next Shot Reminder
⌄
ACTIVE MEDICATIONS
RetatrutideB12
RETATRUTIDE
🔥 14
2
days away
Thursday · 7.5mg
⌄
Medication Supply
Retatrutide
6.2 / 10 mg · Vial
~42 days left · Mar 15
B12
4.4 / 5 ml · Vial
~88 days left · May 8
Retatrutide
1.2 / 5 mg · Vial
~6 days left · refill soon
Medication Levels
7 Days2 Weeks1 Month90 Days
CURRENT LEVEL
5.42mg
Mar 6
Today
ACTIVE MEDICATIONS
RetatrutideRetatrutide
0mg2.7mg5.4mg
18
Total Injections
💉 All time
122/78
Average BP
🩺 mmHg
8.4
Avg Mood
😊 /10
Health Chart
1mAll
218.6lb
↓ 8.4 lb · 3.7%
WeightInjectionsBPMood
2282222162102277.5mg7.5mg4mg10mg218
Feb 6Feb 14Feb 22Mar 2Today
Photos
12 photos · 2w streak
Week 1
Week 7
Today
Scheduled Reminders
Weight
Due today
Mood
Done
Blood Pressure
Tomorrow
Body Measurements
In 3 days
Dashboard
Your complete health overview in one place
🔥
14-day streak
Logged 18 of 18 scheduled shots
Next Shot Reminder
⌄
ACTIVE MEDICATIONS
RetatrutideB12
RETATRUTIDE
🔥 14
2
days away
Thursday · 7.5mg
⌄
Medication Supply
Retatrutide
6.2 / 10 mg · Vial
~42 days left · Mar 15
B12
4.4 / 5 ml · Vial
~88 days left · May 8
Retatrutide
1.2 / 5 mg · Vial
~6 days left · refill soon
Medication Levels
7 Days2 Weeks1 Month90 Days
CURRENT LEVEL
5.42mg
Mar 6
Today
ACTIVE MEDICATIONS
RetatrutideRetatrutide
0mg2.7mg5.4mg
18
Total Injections
💉 All time
122/78
Average BP
🩺 mmHg
8.4
Avg Mood
😊 /10
Health Chart
1mAll
218.6lb
↓ 8.4 lb · 3.7%
WeightInjectionsBPMood
2282222162102277.5mg7.5mg4mg10mg218
Feb 6Feb 14Feb 22Mar 2Today
Photos
12 photos · 2w streak
Week 1
Week 7
Today
Scheduled Reminders
Weight
Due today
Mood
Done
Blood Pressure
Tomorrow
Body Measurements
In 3 days
01BACKGROUND

What Is Retatrutide?

Retatrutide (development code LY3437943, nicknamed "Reta" by the research community) is Eli Lilly's investigational triple hormone receptor agonist. Unlike tirzepatide (Mounjaro/Zepbound) which targets two receptors, Retatrutide activates three: GLP-1, GIP, and Glucagon receptors.

Why glucagon? Adding glucagon receptor activation increases energy expenditure (calorie burning) and promotes fat breakdown in the liver. This third mechanism may explain the superior weight loss results compared to dual agonists.

Administration: Once-weekly subcutaneous injection, similar to Mounjaro and other GLP-1 medications.

02WHAT TO TRACK

The Triple Mechanism

01
🔬
GLP-1 Agonism
Reduces appetite. Slows gastric emptying. Enhances insulin secretion. Same as Ozempic/Wegovy
02
🔬
GIP Agonism
Enhances GLP-1 effects. Improves fat metabolism. Better glucose control. Same as Mounjaro/Zepbound
03
🔬
Glucagon Agonism
Increases energy expenditure. Promotes fat burning. Reduces liver fat. Unique to Retatrutide
04
🔬
Why This Matters
Most weight loss drugs only reduce calorie intake. Retatrutide's glucagon component also increases calorie burning, attacking obesity from both sides. This dual approach—eat less AND burn more—may exp
03KEY NUMBERS

Phase 3 TRIUMPH-4 Results

📈
Avg Weight Loss
0.0%
At the 12mg dose, participants lost an average of 28.7% of their body weight (approx. 71.2 lbs) over 68 weeks. This significantly outperforms Phase 2
💪
Pain Reduction
0%
Retatrutide reduced WOMAC pain scores by approximately 75% (4.5 points), offering substantial relief for osteoarthritis patients. 1 in 8 patients were
🏆
High Response
0.0%
04WHAT TO TRACK

Beyond Weight Loss

01
🎯
Liver Fat Reduction
Retatrutide showed remarkable effects on fatty liver disease (MASLD/MASH). In trials, participants achieved up to 86% reduction in liver fat content.
02
🎯
Metabolic Improvements
Significant HbA1c reduction in diabetics. Improved blood pressure. Better lipid profiles. Reduced inflammation markers. Waist circumference reduction
05DOSING

Expected Dosing Schedule

Weeks 1-4
2mg weekly
Weeks 5-8
4mg weekly
Weeks 9-12
8mg weekly
Week 13+
12mg weekly
06WHAT TO TRACK

Side Effects

01
🔬
Common (GI-Related)
Nausea (most common, dose-dependent). Diarrhea. Vomiting. Constipation. Decreased appetite
02
📊
Trial Observations
Glucagon effect: Unlike some concerns, the glucagon component did not raise blood sugar in trials. The GLP-1 and GIP components effectively counterbalanced any glucose-raising effects.
07TIMELINE

Development Timeline

2023:
Phase 2 results published in NEJM
December 11, 2025:
First positive Phase 3 TRIUMPH-4 readout announced
2026:
Additional TRIUMPH Phase 3 readouts expected across obesity and diabetes
Next:
Regulatory filing and launch timing depend on complete Phase 3 outcomes and revi — Regulatory filing and launch timing depend on complete Phase 3 outcomes and review
08WHAT TO TRACK

Vital Protocol FAQs

01
🔬
Is Retatrutide better than Mounjaro?
Retatrutide's first Phase 3 readout showed very strong efficacy, but direct cross-trial comparisons to Mounjaro/Zepbound are imperfect because populations differ. Mounjaro/Zepbound are approved w
02
🔬
Can I get Retatrutide now?
Retatrutide is not yet approved or available. It's currently in Phase 3 trials. Some research chemical suppliers may sell "research-grade" versions, but these are unregulated, potentially dangerous, a
03
🔬
Will Retatrutide be expensive?
Pricing hasn't been announced, but expect it to be similar to or higher than Mounjaro/Zepbound ($1,000-1,500/month without insurance). Eli Lilly will likely price it as a premium next-generation thera
04
🔬
What indications is Retatrutide being studied for?
Phase 3 trials are evaluating Retatrutide for obesity/overweight, Type 2 diabetes, and MASH (metabolic dysfunction-associated steatohepatitis, formerly NASH). It may receive multiple FDA approvals for
09FAQ

Guide FAQs

Retatrutide (LY3437943) is Eli Lilly's investigational triple agonist (GLP-1/GIP/glucagon), showing up to 28.7% weight loss in Phase 3 TRIUMPH-4. It is also nicknamed "GLP-3" or "GLP3-RT" in research communities.

Yes. GLP-3 (also GLP3 or GLP3-RT) is a community nickname for retatrutide. There is no official "GLP-3 receptor" — the "3" reflects that it is a triple agonist (three receptors), one more than the GLP-1/GIP duals like tirzepatide.

GLP-1 drugs (semaglutide) hit one receptor; "GLP-3"/retatrutide hits three (GLP-1, GIP, glucagon). The added glucagon mechanism raises energy expenditure and reduces liver fat, which is linked to retatrutide's deeper weight loss.

Yes. Shotlee supports tracking Retatrutide doses, side effects, and health metrics. It is free to use.

Free · Always

Track Your Retatrutide Protocol in Shotlee

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📚References & sources

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