Fragment 176-191 (5mg / 10mg)


Size: 5mg / 10mg
Contents: Fragment 176-191
Form: Lyophilized powder
Purity: >99%
SKU: P-FRAG176-191
Availability: In Stock

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Fragment 176-191 Review

Fragment 176-191 peptide, also known as HGH Fragment 176-191, and modified AOD-9604, has been shown in a number of studies on animals to activate weight loss and fat burn in the body, as well as helps raise IGF-1 levels in research subjects.

Human growth hormone (HGH), as the name implies, is essential to human growth and development during their childhood. Additionally, HGH is also a key component that regulates several metabolic functions in the body (1) including inducing hyperglycemic state and maintaining body weight.

HGH deficiency is not uncommon in children, and given the various benefits of the hormone, scientists have developed several synthetic peptides, which are similar to the growth hormone. These synthetic peptides are short, synthetic analogues of the 191 amino acids containing human growth hormone (1).

One of these synthetic HGH peptides is Fragment 176-191, also known as somatotropin (2), which is universally used in weight management and other benefits.


As stated, somatotropin is a synthetic peptide composed of amino acids 176-191, functioning exactly as human growth hormone (2).

Fragment 176-191 induces effects similar to human growth hormone, by means of the same mechanism as the HGH. Somatotropin, also known as Somatropin, is an FDA approved drug having undergone several clinical studies (3). This mechanism and further studies are further described in the article.

Fragment 176-191 History

The importance of the pituitary gland, which secretes the growth hormones, was known in the late 19th century, however, the growth hormone therapy was available to children and adolescents in only the 1950s. During this time, the recombinant technology was not known and hence, HGH benefits were not fully known at the time. With the increased research and implementation of the recombinant technology, growth hormone therapy has changed exponentially (4).

In 1972, the biochemical structure of the growth hormone was completely identified, which helped enormously in the development of the recombinant HGH. The recombinant HGH was first successfully developed in 1979. Later, in 1981, manufacturer Genentech developed the first recombinant HGH (rhGH) via a biosynthetic process (4).

Eventually, an improvised method called protein secretion technology was developed – where the DNA strand of amino acids (which is to be cloned) is isolated and a vector plasmid is isolated from a specific strain of E.coli. Both these isolated components are then cleaved together with the help of enzymes and reformed into a new structure. This new structure is then inserted into the E.coli, which induces the synthesis of the desired protein. This is the most commonly used method to produce the synthetic hormone, now known as somatotropin (4).

How does Frag 176 191 work?

Fragment 176-191, analogous to HGH, stimulates the anterior of the pituitary gland, which speeds up the metabolism rate and actions similar to HGH effects (1).

As a result of this, the peptide induces increased growth and development in children and adolescents.
Additionally, the recombinant human growth hormone, somatotropin, binds with the growth hormone receptors located in several other locations in various tissues, primarily the liver. Once the rhGH binds with the receptors, it stimulates the production of the insulin-like growth factors called IGF-1 and IGF-2 (3).
As a result of the increased IGF factors, the peptide induces glucose homeostasis and high metabolism of carbohydrates and lipids (3).

Fragment 176-191 Peptide Pharmacology


When administered in the dose of 6.0mg via subcutaneous route, the half life of the peptide in healthy humans was determined to be approximately 4.5 hours +/- 2 hours (3).

Mode of elimination

Fragment 176-191 is metabolized in the liver and kidney, most of it being in the kidneys. Once metabolized into smaller amino acids, the breakdown products then re-enter the systemic circulation in the human body (3).

Fragment 176-191 benefits

Below are the main advantages of the peptide:

  • Increased growth rate
  • Increased metabolism rate, leading to better weight management
  • Reduced insulin sensitivity
  • Induced tissue repair effects, similar to the human growth hormone
  • No adverse impact on the lean muscle
  • Potential immune reconstitution properties in HIV patients (3)

Several studies and research conducted are indicative of the fact that the peptide is highly beneficial and produces the above listed effects in the human body. Additionally, studies have been conducted not only on human adults, but also pediatric patients (5) to determine its safety and efficacy while using it as treatment medications for growth hormone deficiency.

Fragment 176-191 Research and Clinical Studies

Studies in pediatric patients for the treatment of growth hormone deficiency:
Growth hormone deficiency (GHD) in children leads to short height, poor height development over the years, weight preservation and prolonged bone age. In infants with decreased growth hormones, there are also signs of hypoglycemia and extended effects of jaundice (5).

Over the years, several studies (5) have been conducted across the globe where GHD pediatrics were administered with the synthetic peptide in varied doses to understand its full potency and effects.
Each study (5) had specific prerequisites including short height, criteria for bone age and growth velocity. Children meeting these criteria were selected for the study.

Studies have shown that when administered intramuscularly, there was complete drug absorption however the antibody formation was limited. Whereas, with subcutaneous administration, the peptide was equally effective, with no side effects and less pain upon administration. Over the years, the recommended dosage frequency changed from twice a week, to thrice weekly and then to daily administration. Additionally, when administered in the evening, it induced higher rates of protein and glucose metabolism than when administered in the morning.

The outcome of the study was that the peptide, when given in doses between 0.17 and 0.23 mg/kg/body weight each week, subcutaneously, during the evening period, yielded the best growth results in children. The dose is increased two to four times during puberty, to depict the same levels as in normal children (without GHD) while having minimal side effects (5).

Studies showing hyperglycemic effects of the peptide

In this study (6), several synthetic HGH peptides were administered both, in vivo and in vitro, in normal functioning rats, including Fragment 176-191, in order to determine its effects on glycogen metabolism.

Upon administration, it was noted that the peptide induced slight increment in levels of blood glucose and lactate, while reduction in the ratio of glycogen synthase in muscle, adipose tissues and in liver. It was determined that this outcome was because the peptide converted the enzymes from their active state to their inactive state, since the synthase levels remained unaffected. The effective dose range was between 0.07 and 7nmols peptide per kg body weight.

Studies showing potential use of medication in HIV-related treatment

Several studies were conducted to understand the role of the peptide as an ‘immune modulator’ in the treatment of HIV associated wasting or cachexia.

In the 2008 study (7), human volunteers undergoing effective ART regimen for HIV for at least 1 year were selected. The study was conducted to determine whether the peptide would increase the thymic function in the body, thereby leading to an increase in total T cell production in HIV patients, who already have low CD4 cell count. Post treatment with the peptide, the outcome was that the peptide elevated the thymic functions in the volunteers, suggesting that the peptide induces thymopoiesis in people who do not have an efficient body immune system.

In the 2010 study (8), similar participants undergoing ART regimen for HIV treatment for the past 1 year were selected. In this study, it was examined whether the peptide increased the production of CD4 cells and thereby elevated the antigen specific responses of CD4 and CD8 cells in the human body. The outcome of this study, after 48 weeks of treatment, was that the peptide led to modest increase in the CD4 cell production in the HIV patients. Hence, it suggested that HIV patients, when treated with rhGH and ART therapy, show significant increase in CD4 cell levels – however, this would yet to be investigated further.

In this 2011 study (9), 278 HIV patients selected for the clinical trial were undergoing ART therapy for at least past one year, and they lacked immune responses upon vaccination towards at least one of the three antigens – namely hepatitis A and B and tetanus. This trial was conducted to investigate whether the peptide induced thymic restoration could also restore cellular immune responses in the body, specific to certain antigens. Post this study, it was noted that the peptide led to the restoration of CD4-specific cellular immune responses in the HIV patients.

Studies showing the use of rhGH in the treatment of diabetic foot ulcers

In this study (10), human volunteers suffering from type I and II diabetes, with known cases of diabetic foot ulcers (DFU) were selected. The patients were divided into 2 groups – the first was the control group treated with alginate dressing, whereas the other was the experimental group treated with both alginate dressing and rhGH treatment of the peptide.

The outcome of this study was debatable. While it showed signs of efficacy in the patients treated with both alginate dressing and peptide, there were also some local symptoms such as pain, deep wounds, bodily secretions and so on. The mechanism by which the peptide treats DFU in humans is not fully known. There are 3 possible mechanisms – one, through promotion of cell proliferation and cell growth, second, through its immunomodulatory properties and third, through angiogenesis. Further studies need to be conducted to fully understand the use and scope of the medication in this treatment.

Fragment 176-191 Side Effects

Studies have been conducted to determine the long-term efficacy and safety of the Fragment 176-191, and the outcomes have been positive. Extremely limited side effects of the peptide have been noted throughout the clinical trials.

Some of the common side effects of the use of the peptide are as follows, which are usually observed in highly sensitive people:

  • For injectables (subcutaneous) – pain, swelling, and redness at the injection site
  • Headaches
  • Elevated levels of sleep, dizziness
  • Palpitations
  • Fatigue
  • Chest tightness

In the several clinical trials conducted on HIV patients, some severe adverse reactions occurred as a result of which studies on those specific individuals had to be discontinued. These are as follows (3):

  • The 2010 clinical trial was discontinued in 8 out of the 60 participants due to the occurrence of carpal tunnel syndrome. One of the patients enrolled for the study was suffering from anal carcinoma, and post the trial, there was progression in this carcinoma, which was suspected to be induced by the peptide treatment.
  • In the 2008 study, 9 out of 22 patients either dropped out of or had their doses reduced prematurely during the study due to signs of adverse reactions. 2 patients suffered from diabetes and one patient showed signs of carpal tunnel syndrome. In other patients, the dose was reduced by minimum 50% because of other known adverse events.
  • In the 2011 study, selected patients showed elevated levels of IGF-1 induced by peptide treatment. Additionally, there were patients who showed signs of peripheral edema and myalgia. Hand edema and carpal tunnel syndrome were other known cases of adverse events reported during the clinical trials in HIV infected patients.

Long term safety and efficacy profile

Studies (11) have been conducted to establish the long-term use and peptide efficacy and safety in humans. Long-term use of the Fragment 176-191 leads to improved body composition, muscle strength, increased bone mass and density, elevated lipid metabolism, and improvement of the quality of life.

It is recommended to elevate the dose of the peptide administration gradually (11) depending on the body response towards medication, in order to ensure the treatment is highly efficacious with minimal side effects. It is, however, mandatory, to monitor the glucose metabolism rates, cardiovascular movements and pituitary responses throughout the treatment.

Fragment 176-191 Dosage

The peptide is now available in several doses and is used at different dose levels depending on its intended use. However, the common peptide dose is 0.17 and 0.23 mg/kg/body weight for efficient growth developmental benefits (5).

It is recommended to use the drug in gradual elevated doses (5), (11), for the best results. If the medication is being administered in pediatric patients, then the dose should be increased during puberty to mimic the same growth hormone levels as in normal children (not suffering from growth hormone deficiency) (5).

Studies have been conducted where the medication was administered both intramuscularly and subcutaneously – and the least amount of pain at the site of administration was reported during subcutaneous administration (5).

Lastly, when Fragment 176-191 is administered during the evening time, it elevates the levels of glucose and protein metabolism in the human body. This was not seen when administered during the morning time. Hence, drug administration during the evening period is recommended as per the studies conducted (5).

Are there any drug interactions with the peptide?

The peptide Fragment 176-191 has the potential to affect the drug elimination process for certain medications that are metabolized by CYP enzymes. Hence, it is recommended to monitor the drug levels in the body while administering the peptide in combination with such compounds (3).

Is Fragment 176-191 banned in sports?

Since the discovery and availability of the recombinant human growth hormone in the early 1990s, the peptides have been in the list of forbidden substances in sports. While it is not known to elevate physical performance rates, the peptide is mainly believed to be used by athletes for its anabolic effects, mainly on muscle growth (12).

There are several methods, both direct and indirect, by which the levels of this peptide are being detected in athletes prior to their sports session. However, given the short half life of the peptide, there are still some difficulties being encountered to detect the presence of the peptide. Till date, the most efficient method of detection has been the direct method including immunoassays (12).


Fragment 176-191 is a synthetic peptide that is similar to the human growth hormone. Over the years, there have been several isolation techniques to develop this peptide – the most recent and efficient technique being the recombinant DNA technology. Fragment 176-191 is a recombinant human growth hormone (rhGH) also commonly known as somatropin (or somatotropin).

Analogous to the human growth hormone, this peptide elevates the rate of growth and development in growth hormone deficient patients. Additionally, rhGH binds with the growth hormone receptors located in several tissues, mainly the liver. Consequently, it elevates the levels of insulin-like growth factors in the body inducing faster metabolism of lipids and carbohydrates.

Pharmacologically, the peptide has a short half-life of 4.5 hours +/- 2 hours and is metabolized in the kidneys and liver. Currently, this peptide, along with other similar rhGH peptides, is banned from sports as it is potentially being used by athletes as a doping agent.

Several research studies have been conducted where it has been indicated that there are multiple health benefits of the peptide. Long term efficacy and safety profile of the medication has been established with minimal side effects reported in healthy individuals. Owing to its immunomodulatory properties, the peptide is also being studied to determine its use, safety and efficacy in HIV infected patients. While positive outcomes have been reported, there were also several cases of adverse events in the HIV infected volunteers – and thus the peptide treatment for these patients is still being explored.


1. Brinkman JE, Tariq MA, Leavitt L, et al. Physiology, Growth Hormone. [Updated 2021 May 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021.

2. National Center for Biotechnology Information (2021). PubChem Compound Summary for CID 16131230, Somatotropin (176-191). Retrieved June 21, 2021.

3. Clinical info drug database.

4. Ayyar V. S. (2011). History of growth hormone therapy. Indian journal of endocrinology and metabolism, 15 Suppl 3(Suppl3), S162–S165.

5. Reh, C. S., & Geffner, M. E. (2010). Somatotropin in the treatment of growth hormone deficiency and Turner syndrome in pediatric patients: a review. Clinical pharmacology : advances and applications, 2, 111–122.

6. G.Y.W. Ma et al, The mechanism of the hyperglycaemic action of synthetic peptides related to the C-terminal sequence of human growth hormone, Biochimica et Biophysica Acta (BBA) – General Subjects, Volume 716, Issue 3, 1982, Pages 400-409, ISSN 0304-4165,

7. Laura A. et al, Growth hormone enhances thymic function in HIV 1-infected results, The Journal of Clinical investigation, 2008 Mar 3, 118(3): 1085-1098.

8. Smith, Kimberly et al. “Treatment with recombinant growth hormone is associated with modest improvement in CD4 lymphocyte reconstitution in HIV-infected persons on antiretroviral therapy: results of ACTG A5174.” AIDS research and human retroviruses vol. 26,4 (2010): 425-32. doi:10.1089/aid.2009.0052.

9. Plana, Montserrat et al. “The reconstitution of the thymus in immunosuppressed individuals restores CD4-specific cellular and humoral immune responses.” Immunology vol. 133,3 (2011): 318-28. doi:10.1111/j.1365-2567.2011.03442.

10. Zhou, Deng-Rong et al. “The effectiveness and safety of recombinant human growth hormone combined with alginate dressing in the treatment of diabetic foot ulcer: A protocol for systematic review and meta-analysis.” Medicine vol. 100,5 (2021): e23984. doi:10.1097/MD.0000000000023984.

11. Svensson J, Johannson G. Long-term efficacy and safety of somatropin for adult growth hormone deficiency. Treat Endocrinol. 2003;2(2):109-20. doi: 10.2165/00024677-200302020-00004. PMID: 15871547.

12. Saugy, M et al. “Human growth hormone doping in sport.” British journal of sports medicine vol. 40 Suppl 1,Suppl 1 (2006): i35-9. doi:10.1136/bjsm.2006.027573.


To get more review details, check out our recent HGH Fragment 176-191 Weight Loss, Benefits, Side Effects blog post. There you can read answers to such topics as What Does HGH Fragment 176-191 Do, HGH Fragment 176-191 and Weight Loss, Fat Burn, and more.


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10 mg, 5 mg