Side-by-side · Research reference

HGH Fragment 176-191vsSermorelin

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

AAnimal-StrongHUMAN-REVIEWED28/59 cited

BPhase 3HUMAN-REVIEWED14/43 cited

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)

Sermorelin

GHRH 1-29 fragment · Short-acting

100–500 mcgPer doseMolteno 2013

Phase 3Evidence levelWalker 1994 Molteno 2013

~12 minHalf-lifeMolteno 2013

SQ · Pre-sleep · 1×/day

01Mechanism of Action

Parameter

HGH Fragment 176-191

Sermorelin

Primary target

Beta-3 adrenergic receptors on adipocytesHeffernan 2001

Pituitary GHRH receptorWalker 1994

Pathway

Fragment → β3-AR upregulation → Enhanced lipolytic sensitivityHeffernan 2001

GHRH-R → Gαs → cAMP → PKA → GH vesicle exocytosisWalker 1994

Downstream effect

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

Pulsatile GH release; subsequent IGF-1 elevationMolteno 2013

Feedback intact?

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

Yes — short pulse preserves feedback

Origin

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

Unmodified active 29-AA fragment of human GHRH (1-44)Walker 1994

Antibody development

Not reported in available studies

—

02Dosage Protocols

Parameter

HGH Fragment 176-191

Sermorelin

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

—

Frequency

Once daily (animal models)

Once daily, pre-sleep

Evidence basis

Animal studies only

Phase 3 (Geref pediatric); clinical practiceWalker 1994 Molteno 2013

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.

—

Standard dose

—

100–500 mcg per injectionMolteno 2013

Lower / starter dose

—

100 mcg per dose

Duration

—

8–12 weeks per cycle

Reconstitution

—

Bacteriostatic water

Timing

—

Pre-sleep, fasted preferred

Half-life

—

~12 min (plasma)Molteno 2013

Shorter than tesamorelin (~26 min) — simpler GHRH analogue.

03Metabolic / Fat Loss Evidence

Parameter

HGH Fragment 176-191

Sermorelin

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

HGH Fragment 176-191

Sermorelin

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.

—

Injection site reaction

—

Mild erythema, transient pain

Flushing / headache

—

Common transient effect

IGF-1 elevation

—

Modest at standard doses

Cancer risk

—

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

Pregnancy / OB

—

Avoid

Glucose handling

—

Generally neutral

Absolute Contraindications

HGH Fragment 176-191

·Competitive athletes (WADA-banned)Cox 2015

Sermorelin

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

Relative Contraindications

HGH Fragment 176-191

·Absence of human safety data — experimental use only

Sermorelin

·Untreated diabetes

05Administration Protocol

Parameter

HGH Fragment 176-191

Sermorelin

1. Route

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

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

2. Frequency

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

SQ — abdomen or thigh. Rotate sites.

3. Duration

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

Pre-sleep, fasted.

4. Storage

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

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

5. Detection

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

29–31G, 4–8 mm insulin syringe.

06Stack Synergy

HGH Fragment 176-191

— no documented stacks

Sermorelin

+ Ipamorelin

Strong

View Ipamorelin →

Sermorelin (GHRH analogue) and ipamorelin (selective GHRP) form the prototypical GHRH+GHRP dual-axis stack at the lowest cost. Both peak within 30 min and produce a sharp physiological GH pulse without cortisol/prolactin elevation.

Sermorelin: 200–300 mcg SQ · pre-sleep
Ipamorelin: 200–300 mcg SQ · same injection
Primary benefit: Pulsatile GH stimulation, recovery, body composition

Raun 1998 Walker 1994