Side-by-side · Research reference

RetatrutidevsVIP

Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.

APhase 2HUMAN-REVIEWED10/41 cited

BPhase 3HUMAN-REVIEWED9/42 cited

Retatrutide

Triple-receptor agonist · Phase 3

1–12 mgWeekly doseJastreboff 2023

24.2%Body-weight ↓Jastreboff 2023

~6 daysHalf-life (est)

SQ · Abdomen · Once weekly

VIP

Neuropeptide · VPAC1/VPAC2 Agonist · Emergency Use Authorization (COVID-19 ARDS)

IntravenousPrimary routeBrown 2023

ARDSLead indicationUdupa 2025

Phase 3Development stage

IV infusion · Inhaled (investigational)Brown 2023 Boesing 2022

01Mechanism of Action

Parameter

Retatrutide

VIP

Primary target

GLP-1R + GIPR + Glucagon receptor (triple agonism)Jastreboff 2023

VPAC1 and VPAC2 G-protein-coupled receptorsUdupa 2025

Pathway

Triple-receptor activation → ↑insulin (GLP-1+GIP), ↓gastric emptying, ↑lipid handling, ↑energy expenditure (glucagon component)Jastreboff 2023

VIP → VPAC1/VPAC2 activation → cAMP elevation → Pulmonary vasodilation + epithelial protection

Downstream effect

Maximal weight loss across class. Glucagon component drives lipolysis and energy expenditure beyond GLP-1+GIP aloneJastreboff 2023

Anti-inflammatory cytokine modulation, alveolar-capillary membrane stabilization, pulmonary smooth muscle relaxation, reduced neutrophil infiltration

Feedback intact?

—

Yes — exogenous VIP acts as physiological agonist

Origin

Synthetic peptide engineered for balanced affinity at three incretin / glucagon receptorsJastreboff 2023

Endogenous 28-amino-acid neuropeptide; synthetic analogue (aviptadil) identical to natural VIP

Antibody development

—

02Dosage Protocols

Parameter

Retatrutide

VIP

Standard dose

12 mg / week (max efficacy)Jastreboff 2023

Phase 2 trial dose. Phase 3 dosing TBD.

—

Frequency

Once weekly

—

Titration schedule

2 mg → 4 mg → 8 mg → 12 mg over 16 weeks

—

Evidence basis

Phase 2 trial; Phase 3 ongoingJastreboff 2023

Phase 3 RCT (TESICO)Brown 2023

816-patient randomized controlled trial in COVID-19 ARDS.

Duration

Indefinite for chronic indication (presumed)

—

Reconstitution

Investigational; not commercially available

Lyophilized powder reconstituted with sterile diluent per protocol

Timing

Any time of day

—

Half-life

~6 days (estimated from class)

~2 minutes (plasma)

Rapid clearance necessitates continuous infusion.

Intravenous (ARDS protocol)

—

60–90 mcg/kg/day via continuous infusion

TESICO trial protocol for COVID-19 ARDS.

Infusion duration

—

12-hour continuous IV infusion dailyBrown 2023

Inhaled (investigational)

—

Variable dosing under clinical trial protocolsBoesing 2022

Delivered via nebulizer for direct pulmonary deposition.

Treatment duration

—

3–14 days (acute ARDS)

04Side Effects & Safety

Parameter

Retatrutide

VIP

GI symptoms

Nausea, vomiting, diarrhea (very common, dose-dependent)Jastreboff 2023

Nausea, diarrhea (VIP is endogenous GI peptide)

Heart rate

↑ resting HR (3–7 bpm at 12 mg)Jastreboff 2023

—

Glucose handling

Glycemic improvement; rare hyperglycemia from glucagon component

—

Pancreatitis risk

Class warning

—

Thyroid C-cell tumours

Class warning (presumed)

—

Pregnancy / OB

Avoid (insufficient data)

—

Hypotension

—

Transient vasodilation-related blood pressure drop

Tachycardia

—

Reflex tachycardia secondary to vasodilation

Infusion site reactions

—

Erythema, phlebitis (IV administration)

Overall tolerability

—

Well-tolerated in Phase 3 trials; adverse event profile comparable to placebo

Absolute Contraindications

Retatrutide

·MTC personal or family history (presumed class effect)
·Pregnancy / breastfeeding

VIP

·Known hypersensitivity to aviptadil or formulation components

Relative Contraindications

Retatrutide

·Severe gastroparesis
·History of pancreatitis
·Severe cardiovascular disease (HR signal)

VIP

·Severe hypotension or shock states (monitor blood pressure)
·Pregnancy — insufficient safety data

05Administration Protocol

Parameter

Retatrutide

VIP

1. Reconstitution

Investigational peptide. Research vials reconstituted with bacteriostatic water per label.

Reconstitute lyophilized aviptadil powder with sterile diluent per manufacturer protocol. Inspect solution for particulates — should be clear and colorless.

2. Injection site

SQ — abdomen, thigh, or upper arm. Rotate weekly.

Administer as continuous 12-hour intravenous infusion via central or peripheral line. Use infusion pump for precise dosing (60–90 mcg/kg/day divided over infusion duration).

3. Timing

Once weekly, same day.

Monitor blood pressure, heart rate, and oxygenation continuously during first infusion. Assess for hypotension and adjust infusion rate if needed.

4. Storage

Refrigerate 2–8 °C. Light-protected.

Deliver via jet or mesh nebulizer per clinical trial protocol. Patient seated upright, normal tidal breathing for 10–15 minutes.

5. Needle

27–31G, 4–8 mm insulin syringe.

Store lyophilized powder at 2–8 °C, light-protected. Reconstituted solution: use immediately or within 24 hours if refrigerated.