Protropin (Somatrem)

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  • Protropin (somatrem) from Genentech


Protropin (Somatrem) Description:

Somatrem is a synthetically manufactured form of human growth hormone (hGH). It is actually a variant of endogenous hGH protein, containing the same sequence of 191 amino acids, but with the addition of an extra amino acid, methionine. For this reason somatrem is commonly described as methionyl human growth hormone. As an hGH medication, somatrem supports the growth of bone, skeletal muscle, connective tissues, and internal organs. It also plays a role in protein, carbohydrate, lipid, and mineral metabolism. In a medical setting, somatrem is used to treat children with growth failure caused by endogenous growth hormone deficiency. When administered as a long-term treatment before linear growth is stopped due to closed epiphyses, the drug may impart a significant positive effect on linear growth. Somatrem is considered to be therapeutically equivalent to growth hormone of pituitary origin. As an hGH drug, somatrem is valued by bodybuilders and athletes for its ability to promote fat loss and muscle and connective tissue growth.

Although somatrem is considered equivalent to human growth hormone, it is not a natural protein to the human body. This may increase the chance for developing antibodies to growth hormone during treatment. The antibodies work by binding with the growth hormone molecule, interfering with its ability to bind receptors and exert activity. In one clinical investigation, 2/3rd of the children treated with somatrem developed antibodies to growth hormone after one year.726 In a similarly configured investigation involving the administration of somatropin for one year, only 1 in 7 patients produced serum antibodies to growth hormone.727 It is important to note that in both studies the antibody reactions were not strong, and did not appear to substantially diminish the ability of the drugs to be therapeutically effective. Diminishment activity (as determined by antibody levels) appears in an very small percentage (<1%) of patients taking somatrem. Still, the correct 191 amino acid configuration of somatropin is considered more desirable to use.


Somatrem was approved for sale in the U.S. in 1985. It was the first synthetic growth hormone medication available worldwide, produced via a manufacturing process called Inclusion Body Technology.728 The technology involves inserting the DNA encoding for the hGH protein into escherichia coli (E.coli) bacteria, which assemble and synthesize the pure protein. Prior to the advent of synthetic growth hormone, hGH was made into a medication only by extracting the natural protein from human corpses. Biological or cadaver hGH, as it was called, was banned in the U.S. in 1985 due to the high prevalence of a rare neurological disease in patients. Somatrem was approved for sale that same year, giving Genentech a short monopoly on the growth hormone market. Within several years, however, other biotechnology companies began selling a form of hGH that was identical to the endogenous protein, called somatropin. Although somatrem remains available in a number of markets including the United States, somatropin is much more widely distributed.

How Supplied:

Somatrem is most commonly supplied in multi-dose vials containing a white lyophilized powder that requires reconstitution with sterile or bacteriostatic water before use. Dosage may vary from 1mg to 10 mg per vial.

Structural Characteristics:

Somatrem is a polypeptide (methionyl human growth hormone) manufactured by recombinant DNA technology. It has 192 amino acid residues and a molecular weight of 22,256 daltons.


Do not freeze. Refrigeration (2º to 8ºC, 35º to 46º F) required before and after reconstitution.

Side Effects (General):

The most commonly reported adverse reactions to somatrem therapy include carpal tunnel syndrome, increased growth of nevi (moles and birthmarks), gynecomastia, and pancreatitis. Note that the side effects of somatrem will generally mirror those of somatropin therapy. The abuse of somatrem may cause diabetes, acromegaly (a visible thickening of the bones, most notably the feet, forehead, hands, jaw, and elbows), and enlargement of the internal organs. Due to the growth promotion effects of human growth hormone, this drug should not be used by individuals with active or recurring cancer.

Side Effects (Impaired glucose tolerance):

Somatrem may reduce sensitivity to insulin and raise blood sugar levels. This may occur in individuals without preexisting diabetes or impaired glucose tolerance.

Side Effects (Injection site):

The subcutaneous administration of somatrem may cause redness, itching, or lumps at the site of injection. It may also cause a localized decrease of adipose tissue, which may be compounded by the repeated administration at the same site of injection.


Somatrem is given by subcutaneous or intramuscular injection. One milligram of somatrem is equivalent to approximately 3 International Units (3IU). When used to treat children with growth failure due to growth hormone deficiency, the drug is applied at a dosage up to .04/mg/kg per day. This equates to a maximum of roughly 10IU per day for a person of approximately 180 lbs. A long-term maintenance dosage is established after reviewing the patient’s IGF-1 levels and clinical response over time, and may be substantially lower than 10IU.

When used for physique- or performance-enhancing purposes, somatrem is usually administered at a dosage between 1IU and 6 IU per day (2-4 IU being most common). The drug is commonly cycled in a similar manner to anabolic/androgenic steroids, with the length of intake generally being between 6 weeks and 24 weeks. The anabolic effects of this drug are less apparent than its lipolytic (fat loss) properties, and generally take longer periods of time and higher doses to manifest themselves.


Somatrem is available in the United States under the Protropin brand name which is distributed by Roche. In Europe and most nations the vast majority of hGH is the correct 191 amino acid sequence somatropin. Somatrem can be found in some markets, however, most commonly in Asia, where it tends to sells for a substantially lower price than somatropin.


726. United Kingdom multicentre clinical trial of somatrem. Milner RD, Barnes ND, Buckler JM, Carson DJ, Hadden DR, Hughes IA, Johnston DI, Parkin JM,
727. Antigenicity and efficacy of authentic sequence recombinant human growth hormone (somatropin): first-year experience in the United Kingdom. Buzi F, Buchanan CR, Morrell DJ, Preece MA. Clin Endocrinol (Oxf ) 1989 May;30(5):531-8
728. Pioneering recombinant growth hormone manufacturing: pounds produced per mile of height. J Pediat 131:55-57.
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By | 2017-04-07T01:10:53+00:00 April 18th, 2015|Categories: Peptides Profiles|0 Comments

About the Author:

William Llewellyn is a researcher in the field of human performance enhancement. He is also author of the bestselling ANABOLICS book series, most recently the ANABOLICS 10th Edition. William is an active supporter of the harm reduction community, and currently serves as honorary lecturer at the Centre for Public Health at Liverpool John Moores University.

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