Side-by-side · Research reference

HexarelinvsSurvodutide

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

APhase 1HUMAN-REVIEWED19/45 cited

BPhase 3HUMAN-REVIEWED25/54 cited

Hexarelin

Hexapeptide GHRP · Cardio-tropic

100–200 mcgPer doseSmith 1996

Phase 1Evidence levelGhigo 1997

~70 minHalf-lifeSemenistaya 2010

SQ · Multiple sites · 1–3×/day

Survodutide

GLP-1/Glucagon Dual Agonist · Phase 3

Once weeklyFrequency

Phase 3Development stageRubino 2026

GLP-1/GCGRDual targetZimmermann 2026

SQ · Once Weekly

01Mechanism of Action

Parameter

Hexarelin

Survodutide

Primary target

Ghrelin receptor (GHS-R1a) + cardiac CD36Smith 1996 Ghigo 1997

GLP-1 receptor and glucagon receptor (GCGR)Yathindra 2026 Zimmermann 2026

Pathway

GHS-R1a → Gαq → Ca²⁺ → GH release. CD36 engagement → direct cardio-tropic actionGhigo 1997

Central: CVOs → hypothalamic appetite regulation. Peripheral: GLP-1R → incretin effect; GCGR → hepatic lipid metabolism, energy expenditureZimmermann 2026 Long 2026

Downstream effect

Strong GH pulse + IGF-1 elevation; cardio-protective effects in animal MI modelsGhigo 1997

Decreased energy intake, increased energy expenditure, improved glucose homeostasis, hepatic fat reductionZimmermann 2026 Yathindra 2026

Feedback intact?

Yes initially; tachyphylaxis with chronic useGhigo 1997

—

Origin

Synthetic hexapeptide His-D-2-Methyl-Trp-Ala-Trp-D-Phe-Lys-NH₂Smith 1996

—

Antibody development

—

02Dosage Protocols

Parameter

Hexarelin

Survodutide

Standard dose

100–200 mcg per injectionSmith 1996

Not yet disclosed (Phase 3 ongoing)

SYNCHRONIZE Phase 3 program underway.Rubino 2026

Frequency

1–2× per day max (tachyphylaxis with chronic 3× daily)

Once weekly

Lower / starter dose

50 mcg per dose

—

Evidence basis

Phase 1 / Phase 2 trialsSmith 1996 Ghigo 1997

Phase 2 RCT (obesity) · Phase 3 ongoing

Duration

4–8 weeks on / 4–8 weeks off (tachyphylaxis mitigation)

—

Reconstitution

Bacteriostatic water

—

Timing

Pre-sleep + fasted preferred

—

Half-life

~70 minSemenistaya 2010

—

Route

—

SubcutaneousYathindra 2026

Phase 2 findings

—

Significant weight loss and metabolic marker improvementYathindra 2026

MASH indication

—

Under investigation for MASH-cirrhosisPatil 2026 Andonie 2026

03Metabolic / Fat Loss Evidence

Parameter

Hexarelin

Survodutide

Primary fat target

—

Total body weight, visceral adipose tissue

Weight loss mechanism

—

Dual action: decreased energy intake + increased energy expenditureZimmermann 2026

Phase 2 efficacy

—

Significant weight loss demonstrated

Specific percentage not disclosed in abstracts.

Metabolic markers

—

Improvements in ALT, AST, LDL levels; significant ALT reduction (MD -22.10 vs placebo)Yathindra 2026 Abulehia 2026 Andonie 2026

MRI-PDFF reduction

—

Hepatic fat reduction demonstrated in MASH trialsAndonie 2026

Network meta-analysis

—

Favorable efficacy profile vs other glucagon receptor agonists

Hepatic requirement

—

Hepatic GCGR required for maximal weight loss and metabolic effectsLong 2026

Energy expenditure

—

Increased energy expenditure contributes to weight lossZimmermann 2026

Comparative efficacy

—

Network meta-analysis shows competitive efficacy in GRA class

04Side Effects & Safety

Parameter

Hexarelin

Survodutide

Cortisol elevation

Modest at high dosesGhigo 1997

—

Prolactin elevation

Modest at high dosesGhigo 1997

—

Hunger

Strong appetite increase via ghrelin agonism

—

Tachyphylaxis

Receptor desensitisation with chronic dosingGhigo 1997

—

Cardiac effects

Direct cardio-tropic; potential benefit in MI but unstudied in humansGhigo 1997

—

IGF-1 elevation

Strong; monitor with chronic high-dose use

—

Cancer risk

Contraindicated in active malignancy (GH/IGF-1 axis)

—

Pregnancy / OB

Avoid

—

GI symptoms

—

Diarrhea, nausea, fatigue — class effect of GLP-1 agonists

Safety profile

—

Network meta-analysis: comparable safety to other GRAs

Serious adverse events

—

Monitored in Phase 2/3; no unique safety signals reported

Detailed SAE data pending Phase 3 completion.

Injection site reactions

—

Expected with subcutaneous administration

Glucagon-related effects

—

Potential for tachycardia, increased blood pressure — theoretical glucagon effect

Absolute Contraindications

Hexarelin

·Active malignancy
·Pregnancy / breastfeeding
·Disrupted hypothalamic-pituitary axis

Survodutide

·Personal or family history of medullary thyroid carcinoma (class effect)
·Multiple endocrine neoplasia syndrome type 2

Relative Contraindications

Hexarelin

·Untreated diabetes
·Severe hyperprolactinemia

Survodutide

·Severe GI disease (inflammatory bowel disease, gastroparesis)
·History of pancreatitis
·Cardiovascular disease (monitor closely for glucagon effects)

05Administration Protocol

Parameter

Hexarelin

Survodutide

1. Reconstitution

Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL = 250 mcg per 0.1 mL.

Specific reconstitution protocol not yet publicly disclosed. Follow manufacturer instructions upon approval.

2. Injection site

SQ — abdomen or thigh. Rotate sites.

Subcutaneous — abdomen, thigh, or upper arm. Rotate sites weekly to minimize injection site reactions.

3. Timing

Pre-sleep + fasted preferred. Cycle on/off to avoid tachyphylaxis.

Once weekly, same day each week. Can be administered at any time of day, with or without meals.

4. Storage

Lyophilised: room temp, light-protected. Reconstituted: refrigerate ≤30 days.

Store refrigerated (2–8 °C) until use. Do not freeze. Protect from light. Specific reconstituted storage duration pending labeling.

5. Needle

29–31G, 4–8 mm insulin syringe.

Subcutaneous injection with appropriate gauge needle (typically 27–31G). Use sterile technique.

06Stack Synergy

Hexarelin

+ CJC-1295 (no DAC)

Strong

View CJC-1295 (no DAC) →

Hexarelin (GHRP) + CJC-1295-no-DAC (GHRH analogue) is the higher-amplitude variant of the standard GHRH+GHRP stack. Hexarelin produces a stronger pulse than ipamorelin but with cortisol + prolactin signal — choose this stack for maximum GH amplitude when side-effect tolerance is acceptable. Cycle aggressively.

Hexarelin: 100 mcg SQ · pre-sleep
CJC-1295 (no DAC): 100 mcg SQ · same injection
Primary benefit: Maximum GH pulse amplitude (with side-effect signal)

Smith 1996 Teichman 2006

Survodutide

— no documented stacks