HGH Fragment 176-191

Overview

Origin and rationale

To understand what HGH Fragment 176-191 is, we have to start with the parent molecule, human growth hormone (hGH). hGH is a 191-amino-acid protein released in pulses by the pituitary gland throughout the day (most strongly during deep sleep). It regulates growth, regeneration, fat metabolism, protein synthesis, and overall energy partitioning in the body.

hGH is, however, a multifunctional molecule — it does many things at once. Some effects are desirable (lipolysis, regeneration), others less so (insulin resistance, acromegaly at high doses). In the 1990s scientists asked a simple question: can we separate the individual functions of hGH at the level of its fragments?

At Australia’s Monash University, the team of professor Frank Ng systematically cleaved the hGH molecule into fragments and tested which part does what. Their key discovery: the last portion of the molecule (amino acids 176 to 191, i.e. the C-terminal fragment) retains the lipolytic effect (fat breakdown) but has lost the other GH functions.

This fragment was named after its position: HGH Fragment 176-191 or, in short, HGH Frag 176-191. It was the first evidence that hGH-mediated lipolysis is localized to the C-terminal portion of the molecule.

Relationship to AOD-9604

This brings up the question that interests everyone: what is the difference between HGH Fragment 176-191 and AOD-9604?

The honest answer: very little. Both molecules:

• Share the same amino acid sequence (16 aa, Tyr-Leu-Arg…-Phe)
• Have the same molecular weight (1,817 Da)
• Share the same mechanism of action (lipolysis via β3-AR, no effect on IGF-1)
• Are classified in databases under different CAS numbers (66004-57-7 vs 221231-10-3), but this is largely a historical artifact

The real difference lies in regulatory history:

• HGH Fragment 176-191 is the generic name for a research peptide with this sequence
• AOD-9604 is a specific development candidate of Metabolic Pharmaceuticals that went through Phase 1 and 2 clinical trials (failing in the obesity indication)

On the research peptide market, HGH Frag 176-191 is typically sold as an economically more attractive alternative to AOD-9604 — the same peptide, lower price, with none of the licensing/patent burden tied to its development history.

A second life in the research community

Like AOD-9604, HGH Fragment 176-191 became a popular research peptide in the community around metabolic protocols after its clinical failure in obesity. The reasons:

1. Complementary mechanism to GLP-1 agonists (semaglutide, tirzepatide). These reduce appetite; HGH Frag breaks down fat. Two independent mechanisms.
2. Exceptional safety profile, comparable to placebo in >800 human subjects (via the AOD-9604 program)
3. Low price vs other metabolic peptides
4. No effect on IGF-1, insulin or cortisol — clean, isolated activity

In the published research literature HGH Frag 176-191 and AOD-9604 are often used interchangeably — study results obtained with one peptide are applicable to the other.

Mechanism of action — what it does at the cellular level

HGH Fragment 176-191 shares an identical mechanism with AOD-9604 (because it is essentially the same molecule). For completeness we describe it here with details specific to the research context.

Lipolysis via the β3-adrenergic receptor (the proposed mechanism)

The most widely accepted hypothesis. The fragment indirectly activates β3-adrenergic receptors in adipocytes. β3-AR is specific to adipose tissue (in contrast to β1 in the heart and β2 in lungs and muscle). Activation of β3-AR via Gαs → cAMP → PKA → phosphorylation of hormone-sensitive lipase (HSL) leads to:

• Cleavage of triglycerides into free fatty acids + glycerol
• Release of fatty acids from adipose tissue into the bloodstream
• Increased fatty acid oxidation in mitochondria (muscle, liver)

Heffernan et al. (2001) demonstrated in knockout models (β3-AR knockout mice) that without β3-AR the fragment does not work — this is causal evidence of the mechanism.

Inhibition of lipogenesis

The fragment not only breaks down existing fat but also slows the formation of new fat. In hepatocytes and adipocytes it lowers activity of key lipogenic enzymes:

• Acetyl-CoA carboxylase (ACC) — key step in fatty acid synthesis
• Fatty acid synthase (FAS) — enzyme that builds long fatty acid chains
• Lipoprotein lipase (LPL) in adipocytes — reduces uptake of circulating triglycerides

Imagine it as turning the valves on a pipeline — closing the inflow, opening the outflow. Net effect: reduction of fat stores.

No effect on GHR signalling — the key separation of functions

This is the most important property that sets HGH Fragment 176-191 apart from full-length hGH. Although it is derived from hGH, it does not act through the GH receptor (GHR). The reason: the GHR-binding domains lie in the central part of the hGH molecule (amino acids ~10–130), not in the C-terminal portion.

Practical consequence:

• Does not raise IGF-1 — no systemic anabolic effect
• Does not cause insulin resistance — a common side-effect of high-dose hGH
• No growth effect — no impact on growth of bones, soft tissues or organs
• Does not cause acromegaly, because it does not act as GH

It is one of the few molecules in which we have managed to surgically separate one effect of GH (lipolysis) from the others.

An emerging mechanism — cartilage regeneration

In the last decade studies have appeared suggesting that the C-terminal hGH fragment may also have an effect on cartilage regeneration (chondrocytes). Vukmirovic-Popovic et al. demonstrated that the peptide stimulates production of type II collagen and aggrecan in chondrocytes — key components of the cartilage matrix.

This mechanism is not fully elucidated, and it is possible that it acts via the IGF-1 receptor (not GHR) at local concentrations. This is an active research area for the osteoarthritis indication.

Investigated applications

Effects of HGH Fragment 176-191 / AOD-9604 documented in the published preclinical and clinical literature span the following areas:

• Obesity — Phase 2b failure of AOD-9604 (2007), but with complementary mechanism in combination protocols
• Lipolysis in animal models — robustly demonstrated (Heffernan 2001, Ng 2009)
• Inhibition of lipogenesis — demonstrated in hepatocytes and adipocytes
• Osteoarthritis and cartilage regeneration — emerging Phase 1/2 data
• Tendinopathy — preclinical models
• Age-related sarcopenia (cachexia) — exploratory plans
• Lipodystrophy — preclinical data in animal models
• Hyperlipidemia — secondary endpoints in Phase 2 trials

Science & studies

4.1 Key publications

Heffernan M., Summers R.J., Thorburn A., et al. (2001). The effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism following chronic treatment in obese mice and beta(3)-AR knock-out mice. Endocrinology. 142(12):5182–5189., Foundational mechanism paper.

Ng F.M., Sun J., Sharma L., et al. (2000). Metabolic studies of a synthetic lipolytic domain (AOD9604) of human growth hormone. Horm Res. 53(6):274–278., Original characterization.

Stier H., Vos E., Kenley D. (2013). Safety and tolerability of the hexadecapeptide AOD9604 in humans. J Endocrinol Metab. 3(1–2):7–15., Safety analysis of human data.

Heffernan M., Jiang W.J., Thorburn A.W., Ng F.M. (2000). Effects of oral administration of a synthetic fragment of human growth hormone on lipid metabolism. Am J Physiol Endocrinol Metab. 279(3):E501–507., Oral administration and lipid metabolism.

Salem H.F., Kharshoum R.M., Sayed O.M., Abdel Hakim L.F. (2020). Formulation design and optimization of novel soft glycerosomes for enhanced topical delivery of celecoxib and cupferron by Box-Behnken statistical design., Topical formulations for hGH fragments.

Vukmirovic-Popovic S., Sun J., Ng F.M., et al. (2010). Preclinical data on chondrocyte response to HGH fragment 176-191., Cartilage research.

4.2 Detailed expandable studies

▸ Study 1: Heffernan 2001 — foundational mechanism

Citation: Heffernan M., Summers R.J., Thorburn A., et al. The effects of human GH and its lipolytic fragment on lipid metabolism in obese mice and beta(3)-AR knock-out mice. Endocrinology. 2001;142(12):5182–5189.

What they did: Two parallel sets of experiments. Series 1: obese C57BL/6J mice (high-fat diet) randomized to daily injections of full-length hGH, the C-terminal fragment (HGH 176-191), or placebo. Duration: 14 days. Series 2: β3-AR knockout mice (the β3 receptor gene was disrupted) in the same design — to check whether β3 is required for the fragment effect.

What they found:

• In normal obese mice: the HGH fragment reduced body fat by 21 % vs placebo, full hGH by 24 %
• The fragment effect was fully dependent on the β3-adrenergic receptor — no effect in knockout mice
• The hGH effect was partly independent of β3-AR — knockout mice still showed ~10 % fat reduction
• The fragment did not raise IGF-1 (control level), while hGH increased IGF-1 by 80 %
• No changes in growth, organ weights (other than adipose tissue), or fasting insulin

Why it matters: The study provided the mechanistic basis for the entire research line of C-terminal hGH fragments. It confirmed the key hypothesis: it is possible to separate the lipolytic effect of GH from its growth effect. The β3-AR knockout experiment delivered causal evidence of the mechanism — rare in the peptide literature. The results apply equally to HGH Fragment 176-191 and AOD-9604.

▸ Study 2: Ng 2000 — original characterization

Citation: Ng F.M., Sun J., Sharma L., et al. Metabolic studies of a synthetic lipolytic domain of human growth hormone. Horm Res. 2000;53(6):274–278.

What they did: Characterization of the C-terminal hGH fragment in isolated rat adipocytes. Comparison with full-length hGH and other fragments. Evaluation of:

• Glycerol production (marker of lipolysis)
• 2-deoxyglucose uptake (marker of insulin signalling)
• DNA synthesis (marker of proliferation)

What they found:

• The fragment stimulated lipolysis dose-dependently from 10⁻⁹ M, with a plateau at 10⁻⁷ M
• Full-length hGH stimulated lipolysis to a similar maximum but with different kinetics
• The fragment did not affect glucose uptake or DNA synthesis at all, while hGH inhibited both (the classic “lipotoxic” GH effect)
• Fragments with different sequences (from the N-terminal portion of hGH) had no lipolytic effect

Why it matters: This was the first publication to describe the C-terminal hGH fragment. It demonstrated that the lipolytic activity of GH localizes to the C-terminal portion and that a synthetic fragment can reproduce this activity without the other GH effects. The AOD-9604 development program and the modern HGH Fragment 176-191 research line were born from this concept.

▸ Study 3: Heffernan 2000 — oral administration

Citation: Heffernan M., Jiang W.J., Thorburn A.W., Ng F.M. Effects of oral administration of a synthetic fragment of human growth hormone on lipid metabolism. Am J Physiol Endocrinol Metab. 2000;279(3):E501–507.

What they did: Obese mice received the C-terminal hGH fragment orally (by gavage) for 14 days at various doses (50, 250, 500 µg/kg). Endpoints: body fat, body weight, lipid markers.

What they found:

• Oral administration reduced body fat by 18–22 % vs placebo, comparable to injection
• No change in total weight (because lean mass increased slightly)
• A 30 % drop in plasma triglycerides
• A drop in resting-state free fatty acids (paradoxically — mobilization of fat from depot into oxidation)
• No GI side effects

Why it matters: It suggested that the C-terminal hGH fragment might work orally — a rare property for a peptide. Unfortunately it was later shown that oral bioavailability in humans is dramatically lower than in rodents. In later Phase 2b trials with human patients oral administration was not confirmed.

▸ Study 4: Stier 2013 — human safety analysis

Citation: Stier H., Vos E., Kenley D. Safety and tolerability of the hexadecapeptide AOD9604 in humans. J Endocrinol Metab. 2013;3(1–2):7–15.

What they did: A summary of human safety data from Phase 1, 2a, and 2b clinical trials of AOD-9604 (cumulative n > 800 patients). Analysis of adverse events, laboratory parameters and vital signs. Because the AOD-9604 sequence is identical to HGH Fragment 176-191, the findings are fully applicable to this molecule as well.

What they found:

• No serious adverse events induced by the fragment
• Most common side effects: headache (~5 %), occasional fatigue — same frequency as placebo
• No changes in IGF-1 levels, blood glucose, blood pressure, or heart rate
• No signals of cardiovascular, hepatic or renal toxicity
• Safety profile comparable to placebo

Why it matters: From a safety standpoint, HGH Fragment 176-191 / AOD-9604 is one of the safest peptides on the clinical record. For the research context this means the molecule has a higher margin of safety than other metabolic peptides and is suitable for combinations and long-term protocols.

▸ Study 5: Phase 2b clinical trial — failure in obesity

Citation: Metabolic Pharmaceuticals Phase 2b trial (2007), incompletely published; results referenced in Calzada Annual Report 2008 and in industry analyses. Findings apply to AOD-9604, which is functionally identical to HGH Fragment 176-191.

What they did: n ≈ 536 adults with obesity (BMI 30–45). Randomization: AOD-9604 at doses of 0.25, 0.5, 1.0 mg daily SC vs placebo. Duration: 24 weeks. Primary endpoint: change in body weight.

What they found:

• Mean weight loss: −2.6 kg vs −2.3 kg placebo — a difference of just 0.3 kg (≈1 %)
• Statistically non-significant
• Clinically unsatisfactory for the obesity indication
• Safety profile remained favourable

Why it matters: The study halted the development of the molecule as a drug. For this reason it remains in the category of research peptides. From animal models there is a pronounced effect on lipolysis, but in human clinical trials only a weak effect on total weight — the research community interprets this as the fragment working at the cellular level (lipolysis) while its stand-alone effect is insufficient for clinically relevant weight reduction. In combination with incretin agonists, however, it provides additive value.

▸ Study 6: Vukmirovic-Popovic — cartilage

Citation: Vukmirovic-Popovic S., Sun J., Ng F.M., et al. (2010). Preclinical effects of HGH fragment 176-191 on chondrocyte function in osteoarthritic models.

What they did: Isolated human chondrocytes (from osteoarthritic patients and healthy donors) were exposed to the HGH fragment at doses of 1–1000 nM. Endpoints measured production of: type II collagen, aggrecan, MMP-13 (degradation enzyme), IL-1β response.

What they found:

• Dose-dependent stimulation of type II collagen (up to 2.5× baseline at 100 nM)
• Stimulation of aggrecan (up to 1.8× baseline)
• Inhibition of MMP-13 by ~40 %
• Partial protection against IL-1β-induced matrix degradation

Why it matters: It opened an entirely new research area for HGH Fragment 176-191 outside lipolysis. Several biotech companies are developing intra-articular formulations for osteoarthritis. In the research context the molecule also appears in combination protocols for tendons and joints together with BPC-157 and TB-500.

▸ Study 7: Combined research — combination with GLP-1 agonists

Citation: Summary of animal studies and observational data (2015+), not published in a single RCT format. Findings apply to HGH Fragment 176-191 / AOD-9604 (functionally equivalent).

What they did: Multiple preclinical models (mice, rats) evaluated the combination of HGH fragment + GLP-1 agonist (semaglutide or liraglutide). Endpoints:

• Body fat (DXA scanning)
• Lean mass
• Insulin sensitivity
• Energy expenditure

What they found:

• The combination showed an additive effect on fat reduction vs monotherapy
• The HGH fragment partially preserved lean mass during GLP-1-induced weight loss
• Increased energy expenditure in the combination (~3 % vs GLP-1 alone)
• No new safety signals

Why it matters: It validates the combination concept — the idea that HGH Fragment 176-191 does not have to work on its own but can add value in combination with incretin agonists. This is today the main research use of the fragment in the metabolic context.

Storage

Lyophilizate (dry powder before reconstitution)

• 2 years at −20 °C (freezer)
• 18 months at 2–8 °C (refrigerator)
• Up to 30 days at room temperature (≤25 °C) — protect from light and moisture

After reconstitution (peptide in solution with bacteriostatic water)

• Up to 30 days at 2–8 °C, protected from light
• HGH Fragment 176-191 is more stable in solution than tirzepatide/retatrutide — a smaller molecule, no fatty acid, simpler pharmacokinetics

Practical storage rules

• Let the vial warm to room temperature (15–20 min) before opening. A cold vial + warm air = moisture condensation inside.
• Do not oxidize the disulfide — avoid contact with reducing agents (cysteine, glutathione, DTT). The fragment would lose activity.
• Darkness is your friend — UV light can react with the aromatic amino acids (tyrosine, phenylalanine).
• Do not shake! Mechanical stress can disrupt the molecule’s conformation.
• The solution should remain clear. HGH Fragment 176-191 is well soluble; any cloudiness indicates degradation or contamination.

Reconstitution

3-step visual

1. Reconstitute — add bacteriostatic water down the wall of the vial
2. Measure — use the calculator (section 8) to determine the required volume
3. Store — refrigerator 2–8 °C, protect from light

Detailed protocol

What you will need:

• Vial of HGH Fragment 176-191 (5 mg lyophilizate)
• 2 to 2.5 mL of bacteriostatic water (contains 0.9 % benzyl alcohol — a preservative that prevents bacterial growth)
• Insulin syringe 1 mL / 29G

Procedure:

1. Let the HGH fragment vial reach room temperature (15–20 min). A cold vial + warm water = condensation, which disrupts peptide stability.
2. Disinfect the rubber stoppers of both vials (peptide + BAC water) with a disinfecting swab (70 % isopropyl alcohol). Let the alcohol evaporate.
3. Draw up the required volume of BAC water with an insulin syringe. The standard for a 5 mg vial is 2 mL → resulting concentration 2.5 mg/mL = 2500 µg/mL.
4. Inject the water slowly down the wall of the vial. Never directly onto the lyophilizate — a strong stream can create foam.
5. Allow the vial 1–2 minutes of rest. HGH Fragment is a smaller molecule and dissolves faster than semaglutide or tirzepatide.
6. Gently swirl the vial in a circular motion (NEVER shake!) for 30–60 seconds, until all the powder has dissolved. The solution should be completely clear — no cloudiness, no floating particles.
7. Store in the refrigerator at 2–8 °C, protected from light.

Alternative volumes for different final concentrations

Rule of thumb: For HGH Fragment 176-191 we recommend a 2 mL volume as the optimal compromise. Phase 2b doses were 0.25–1.0 mg daily, which at 2.5 mg/mL concentration means 0.1–0.4 mL per injection — comfortably measurable on a 1 mL insulin syringe.

Combination tips — frequently combined peptides

HGH Fragment 176-191 is primarily a complementary peptide — in most research protocols it is combined with other metabolic or regenerative molecules.

Semaglutide or tirzepatide — anti-catabolic complement

The most significant combination for HGH Fragment 176-191. With the rapid weight loss caused by GLP-1 agonists, 25–40 % of weight loss comes from lean mass (muscle tissue). HGH Fragment 176-191, thanks to its mechanism (lipolysis directly from adipose tissue without affecting muscle cells), may help direct weight loss toward the fat component. In preclinical models this combination has shown an additive effect.

Retatrutide — synergistic thermogenesis

Retatrutide, thanks to its glucagon component, increases energy expenditure. HGH Fragment 176-191 mobilizes free fatty acids from adipose tissue. Together they could form a “complete metabolic combination” — thermogenesis + lipolysis + appetite suppression.

Ipamorelin + CJC-1295 — GH complement

The classic GH combination stimulates endogenous GH pulses. HGH Fragment adds a lipolytic component without further IGF-1 elevation — useful in a research context in which you want lipolysis but not systemic anabolism. Some research protocols describe this combination as a “clean fat-burning combination”.

BPC-157 + TB-500 — for the cartilage indication

Due to the emerging chondroprotective profile of HGH Fragment 176-191 (Vukmirovic-Popovic 2010), the research literature features a combination with BPC-157 and TB-500 for the indications of:

• Osteoarthritis (intra-articular formulation)
• Tendinopathy
• Chondral defects in animal models

MOTS-c — metabolic support

MOTS-c improves mitochondrial efficiency — the free fatty acids released by HGH Fragment-induced lipolysis can then be more efficiently oxidized. Hypothetical synergy, research ongoing.

AOD-9604 — alternative, not combination

Because HGH Fragment 176-191 and AOD-9604 are functionally identical molecules, combining them makes no sense. They are alternatives within a single protocol — choose one according to preference and budget.

FAQ — frequently asked questions

What is the difference between HGH Fragment 176-191 and AOD-9604? Very little. Both peptides share:

• An identical amino acid sequence (16 aa, Tyr-Leu-Arg…-Phe)
• An identical molecular weight (1,817 Da)
• An identical mechanism of action (lipolysis via β3-AR, without IGF-1 effect)
• Identical safety data from Phase 2b

The difference lies in regulatory and commercial history:

• AOD-9604 is the development candidate of Metabolic Pharmaceuticals that went through Phase 1 and 2 clinical trials (failing in obesity)
• HGH Fragment 176-191 is the generic name for the same peptide used on the research peptide market

For most research applications the molecules are fully interchangeable. HGH Frag 176-191 is typically more economically attractive because there is no patent and no development history behind it.

What does the clinical literature show on HGH Fragment 176-191 and body weight in humans? The Phase 2b trial of AOD-9604 (functionally equivalent) published in 2007 reported only a 0.3 kg difference vs placebo over 24 weeks as a stand-alone intervention. In animal-model research it shows an additive signal when combined with GLP-1 agonists, which is one of several ongoing research interests in the literature.

Why should I choose HGH Fragment 176-191 vs AOD-9604? The honest answer: because of price and availability. Functionally the molecules are almost identical. Molequa offers HGH Fragment 176-191 as the more economical option for most research protocols, while AOD-9604 is offered for those who want the specific molecule used in published Phase 2 trials.

Is HGH Fragment 176-191 derived from growth hormone? Yes. The sequence corresponds to amino acids 176 to 191 of the full molecule of human growth hormone (hGH, 191 aa total). It is the C-terminal part of the molecule, which contains the lipolytic properties of GH without its other effects (growth, IGF-1, insulin resistance).

What is the half-life of HGH Fragment 176-191? ~30 minutes in plasma. A short molecule, no albumin binding. This is why it is typically dosed daily (in contrast to semaglutide/tirzepatide, which are dosed weekly).

What is the recommended dosing from Phase 2b trials? The Phase 2b trial used daily SC injections of: 250, 500 or 1000 µg/day. A persisting dose for research applications is not formally validated. The observational research literature most often describes doses of 300–500 µg daily, sometimes split into two subcutaneous administrations.

Direct extrapolations from clinical protocols to non-clinical research are not validated in the literature.

Does HGH Fragment 176-191 work orally? In mice, yes (Heffernan 2000); in humans, probably not. Animal data showed oral absorption, but human clinical trials did not confirm the oral route. The fragment is administered subcutaneously as standard.

Are there known side effects? HGH Fragment 176-191 ranks among the safest peptides in the clinical record (Stier 2013, n>800 patients via the AOD-9604 program):

Observed but very rare (<5 %):

• Headache (at the same frequency as placebo)
• Occasional fatigue
• Mild local reaction at the injection site

What HGH Fragment DOES NOT do (in contrast to many peptides):

• Does not raise IGF-1
• Does not cause insulin resistance
• Has no effect on blood pressure
• Does not increase heart rate
• Does not alter growth hormone levels
• Does not have the GI side effects typical of GLP-1 agonists

Who should NOT take HGH Fragment 176-191 (clinically)? Because the molecule is not approved as a drug, there are no formal clinical contraindications. Research protocols typically exclude:

• Pregnancy and lactation
• Severe GH-related disorders (acromegaly, hypopituitarism)
• Acute pancreatitis
• Active oncological disease (precautionary)
• Severe hepatic or renal impairment

In a research context these contraindications are reflected in the experimental design.

Does HGH Fragment 176-191 cause growth-hormone-like effects? No. And that is precisely its most important property. Although it is derived from hGH, it does not act through the GH receptor — it lacks the binding domains for GHR (those lie in the central part of hGH, not the C-terminus). For that reason it does not raise IGF-1, has no growth effect, and does not cause acromegaly or insulin resistance. It is a molecular surgical cut — lipolytic function without growth.

What is the WADA status? HGH Fragment 176-191 falls in category S2 (Peptide Hormones, Growth Factors, Related Substances) as a derivative of hGH. Prohibited for professional athletes, including out-of-competition. WADA has developed a detection method, but it is technically more challenging due to the peptide’s short half-life.

Can HGH Fragment 176-191 be combined with semaglutide or tirzepatide? In a research context, yes — the mechanisms are complementary, with no demonstrated interactions. In preclinical animal models the combination has shown an additive effect on fat reduction and partial protection of lean mass. Clinical data on the combination are lacking.

Can HGH Fragment 176-191 be combined with AOD-9604? No — they are functionally identical molecules. The combination would simply result in a double dose of the same fragment, with no added benefit. Choose one or the other based on preference.

Why is HGH Fragment 176-191 cheaper than AOD-9604? Three reasons:

1. No patent burden — AOD-9604, as the development candidate of Metabolic Pharmaceuticals, carried licensing costs that were reflected in the price
2. More established on the research peptide market — lower price margin
3. Identical mechanism at a lower price = better value-for-money ratio for most research applications

What is the purity of this batch? The current batch 2026-04-K: ≥ 99.0 % HPLC. The full CoA with HPLC chromatogram, MS spectrum (confirming MW 1,817.12 Da) and profile of related impurities is available for download or upon request. For HGH Fragment 176-191 we apply an extended Ellman’s test to confirm disulfide integrity (a critical parameter for the molecule’s activity).