Side-by-side · Research reference

HexarelinvsHGH Fragment 176-191

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

BAnimal-StrongHUMAN-REVIEWED28/59 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

HGH Fragment 176-191

GH Fragment · Pre-Clinical

50%Weight gain reductionNg 2000

~26 minHalf-life (est.)

No IGF-1 ↑GH axis impact

SQ · IP (animal) · Oral (tested)

01Mechanism of Action

Parameter

Hexarelin

HGH Fragment 176-191

Primary target

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

Beta-3 adrenergic receptors on adipocytesHeffernan 2001

Pathway

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

Fragment → β3-AR upregulation → Enhanced lipolytic sensitivityHeffernan 2001

Downstream effect

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

Increased lipolysis and beta-3 AR mRNA expression without IGF-1 axis activation

Feedback intact?

Yes initially; tachyphylaxis with chronic useGhigo 1997

N/A — does not interact with GH/IGF-1 axis

Origin

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

Synthetic peptide derived from hGH residues 176-191; AOD9604 includes N-terminal tyrosine (177-191)Cox 2015

Antibody development

—

Not reported in available studies

02Dosage Protocols

Parameter

Hexarelin

HGH Fragment 176-191

Standard dose

100–200 mcg per injectionSmith 1996

—

Frequency

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

Once daily (animal models)

Lower / starter dose

50 mcg per dose

—

Evidence basis

Phase 1 / Phase 2 trialsSmith 1996 Ghigo 1997

Animal studies only

Duration

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

—

Reconstitution

Bacteriostatic water

—

Timing

Pre-sleep + fasted preferred

—

Half-life

~70 minSemenistaya 2010

—

Animal dose (oral)

—

500 mcg/kg body weightNg 2000

Obese Zucker rats, 19 days.

Animal dose (IP)

—

Not specified (14-day chronic administration)Heffernan 2001

Obese mice, daily IP injection.

Human equivalent dose

—

Not established — no published human RCTs

Duration tested

—

14–19 daysHeffernan 2001 Ng 2000

Detection window

—

50 pg/mL LOD in urine; stable metabolite extends detectionCox 2015

WADA-banned; anti-doping testing available.

Oral bioavailability

—

Demonstrated efficacy in animal oral administrationNg 2000

Potential for oral therapeutic development.

03Metabolic / Fat Loss Evidence

Parameter

Hexarelin

HGH Fragment 176-191

Primary fat target

—

Adipose tissue (general) — beta-3 AR mediated lipolysisHeffernan 2001

Weight gain reduction

—

50% reduction vs control (15.8 ± 0.6 g vs 35.6 ± 0.8 g)Ng 2000

Obese Zucker rats, 19 days oral administration.

Body fat reduction

—

Significant decrease in body weight and body fat in obese mice (14 days)Heffernan 2001

Lipolytic activity

—

Increased adipose tissue lipolytic activityNg 2000

Direct measurement in treated animals.

Beta-3 AR expression

—

Upregulated β3-AR mRNA in obese mice to lean-comparable levelsHeffernan 2001

Insulin sensitivity

—

No adverse effect — euglycemic clamp confirmedNg 2000

Contrasts with intact hGH diabetogenic effects.

IGF-1 impact

—

No elevation — fragment does not activate GH/IGF-1 axis

Beta-3 AR dependency

—

Effect abolished in β3-AR knockout miceHeffernan 2001

Confirms β3-AR as primary mechanism.

Route of administration

—

Efficacy demonstrated via oral and IP routesNg 2000 Heffernan 2001

Human evidence

—

None published — pre-clinical only

04Side Effects & Safety

Parameter

Hexarelin

HGH Fragment 176-191

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

—

Insulin sensitivity

—

No adverse effects observed in euglycemic clamp (animal)Ng 2000

GH/IGF-1 axis

—

No activation — avoids diabetogenic effects of full GHNg 2000

Human safety data

—

Not available — no published human trials

WADA status

—

Banned as performance-enhancing drugCox 2015

Metabolic profile

—

Six metabolites identified; CRSVEGSCG most stableCox 2015

Detection window implications for doping control.

Absolute Contraindications

Hexarelin

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

HGH Fragment 176-191

·Competitive athletes (WADA-banned)Cox 2015

Relative Contraindications

Hexarelin

·Untreated diabetes
·Severe hyperprolactinemia

HGH Fragment 176-191

·Absence of human safety data — experimental use only

05Administration Protocol

Parameter

Hexarelin

HGH Fragment 176-191

1. Reconstitution

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

Subcutaneous injection primary route in research context. Oral administration demonstrated efficacy in animal models at 500 mcg/kg.

2. Injection site

SQ — abdomen or thigh. Rotate sites.

Once daily dosing used in animal studies. Timing not specified; GH-independent mechanism suggests flexibility.

3. Timing

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

Animal protocols: 14–19 days. Human duration not established — no published trials.

4. Storage

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

Lyophilized peptide storage per standard peptide protocols. Metabolite stability suggests refrigerated reconstituted solution viable.

5. Needle

29–31G, 4–8 mm insulin syringe.

Detectable in urine via SPE-LC-MS at 50 pg/mL LOD. Extended detection window via stable metabolite CRSVEGSCG.Cox 2015

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

HGH Fragment 176-191

— no documented stacks