What is HGH somatropin? Identity, recombinant origin and verification
Somatropin is the International Nonproprietary Name for human growth hormone produced by recombinant DNA technology (rhGH). In lab practice and reference catalogs it also goes by HGH somatropin, somatropin, or rhGH. This article covers only what the published literature says about the molecule: what it is, how it is made, how its identity is verified, and what its protein nature implies for lab handling. We do not cover clinical use.
What somatropin is as a molecule
Somatropin is a 191-amino-acid protein weighing about 22 kDa (roughly 22,125 Da), held together by two disulfide bonds. Its sequence is identical to the growth hormone the pituitary makes naturally. By international convention, the name somatropin is reserved for preparations that replicate that sequence exactly. An earlier variant, somatrem, carried one extra amino acid (a methionine) at the start of the chain, a leftover from the first manufacturing processes.
Because it is a protein, somatropin does not behave like a short synthetic peptide. It is sensitive to heat, and over time slightly modified versions of the molecule can appear. Those variants show up as separate peaks in chromatography and are detectable by mass spectrometry.
How it is made: recombinant origin
Bacterial expression of human growth hormone was first described in 1979 by Goeddel and colleagues in Nature. They built a hybrid gene, part chemically synthesized DNA and part enzymatically prepared cDNA, and expressed it in Escherichia coli under the lac promoter, producing a polypeptide with the size and immunological properties of mature hGH. That work laid the technical groundwork for later industrial somatropin processes.
Today's commercial processes are variations on the same idea: grow E. coli carrying the inserted gene, extract the protein, purify it through several chromatography steps, and verify that the sequence and purity match what the pharmacopoeia requires.
How identity and purity are verified
Characterization of recombinant somatropin depends on a combination of physicochemical methods. Bioassays were replaced, for routine batch release, with objective analytical techniques. The usual axes are four.
Reversed-phase high-performance liquid chromatography (RP-HPLC). The technique separates the components in the batch and shows somatropin as a main peak; modified variants (from age or from the manufacturing process) show up as neighboring peaks and are counted as product-related impurities. Our article on HPLC purity explains how to read that figure on a COA.
Peptide mapping after tryptic digestion. This is the identity test the pharmacopoeia requires. The protein is cut into fragments with an enzyme (trypsin), the resulting pattern is separated, and it is compared with the pattern from a reference standard. If the two patterns match, the sequence is what it should be.
Mass spectrometry (MS). Applied to intact protein and to tryptic peptides, MS confirms the molecular mass, detects variants (Met oxidation, Asn/Gln deamidation, truncated or aggregated species), and assigns each observed HPLC peak.
International reference standard. For potency readings and cross-laboratory calibration, the current reference material is the WHO Second International Standard for Somatropin, code NIBSC 98/574, established after an international collaborative study of 16 laboratories and reported by Bristow and Jespersen in 2001.
A serious somatropin certificate of analysis (COA) names these techniques: HPLC for purity, MS for mass identity, tryptic mapping for sequence identity, and a quantitative comparison against the international standard or an in-house standard traceable to it. Our article on how to read a peptide COA covers the rest of the document.
Égida's HGH COA references these same techniques. Every batch includes HPLC purity, intact-mass MS identity, and tryptic mapping against a standard traceable to NIBSC 98/574. You can see the current-batch specs on the product page or request the COA by email before ordering.
What this means for lab handling
Somatropin ships lyophilized. In dry form it is reasonably stable at refrigeration temperatures; in solution it is a mid-sized folded protein and therefore sensitive to temperature, mechanical agitation, UV light, freeze-thaw cycles, and solvent quality. Our articles on peptide reconstitution and bacteriostatic vs. sterile water cover general principles for handling lyophilized material; the peptide calculator converts concentration to volume unambiguously.
For research on the molecule, what matters at the purchase stage is full traceability: batch number, COA with HPLC + MS + tryptic mapping, comparison against a traceable standard, and lot-to-lot consistency. Details on somatropin price, presentation, and per-batch COA live on the product page; to buy HGH mexico with a verifiable COA, that same page is the internal reference. HGH somatropin sits in the catalog of research peptides alongside incretin analogs and repair peptides.
What you'll find in an Égida HGH batch
Égida HGH (somatropin) ships as a 12 IU lyophilized vial, research grade (RUO). Every batch comes with a Certificate of Analysis that reports the four readings described above: HPLC purity, intact-protein mass identity by MS, sequence identity by tryptic mapping, and a quantitative comparison against a standard traceable to the WHO international reference. The COA carries its own batch number, analysis date, and lab technical sign-off; it can be requested before a purchase quote.
Per-batch traceability is what separates serious research material from generic commercial supply. The HGH somatropin price is listed on the product page (from $480 MXN for the 12 IU vial), and every order ships with the COA for the specific batch you receive — not a static reference sheet.
FAQ
Are somatropin and HGH the same thing?
"HGH" is the abbreviation for human growth hormone and is used as a generic term for the hormone. "Somatropin" is the International Nonproprietary Name that specifically designates the version produced by recombinant DNA with the same 191-amino-acid sequence as pituitary hGH. In commerce the terms are used interchangeably, but somatropin implies recombinant origin and a sequence identical to native hGH.
How is somatropin different from somatrem?
Somatrem is an earlier form of recombinant hGH with an added N-terminal methionine (met-hGH), a consequence of the first expression systems. Modern somatropin lacks that extra residue and matches the native 191-amino-acid pituitary sequence exactly.
What is its molecular weight?
Approximately 22,125 Da (~22 kDa). That figure, measured by intact-protein mass spectrometry, is one of the primary identity criteria on a somatropin COA.
What is the NIBSC 98/574 standard?
It is the WHO Second International Standard for Somatropin, distributed by NIBSC as lyophilized reference ampoules with a declared specific activity. It is used to calibrate assays and to allow quantitative comparisons between laboratories.
Request the current-batch COA
If you are considering buying HGH somatropin from Mexico for research, message us by email with the presentation you need: we send the current-batch Certificate of Analysis (HPLC + MS + tryptic mapping against a standard traceable to NIBSC 98/574), an updated quote, and discreet shipping times. Email us for the COA →
Sources
- Goeddel DV, Heyneker HL, Hozumi T, et al. Direct expression in Escherichia coli of a DNA sequence coding for human growth hormone. Nature. 1979;281(5732):544–548. PMID: 386136.
- Bristow AF, Jespersen AM. The second international standard for somatropin (recombinant DNA-derived human growth hormone): preparation and calibration in an international collaborative study. Biologicals. 2001;29(2):97–106. PMID: 11580214.
- Bayol A, Bristow A, Charton E, Girard M, Jongen P. Somatropin and its variants: structural characterization and methods of analysis. Pharmeuropa Bio. 2004;2004(1):35–45. PMID: 15659284.