What is ?

01

What it is

Its sequence, in one-letter amino-acid code, is YLRIVQCRSVEGSCGF. The Y is the added tyrosine; the rest is the final stretch of growth hormone’s 191-amino-acid chain. A disulfide bond (a sulfur-to-sulfur link) joins the cysteines at positions 7 and 14, closing a loop of eight residues.

The reference record lists the formula C78H123N23O23S2 and an average molar mass of about 1,815 g/mol (PubChem CID 71300630), under a tenth of growth hormone’s roughly 22,000 g/mol.

Sources: [1] PubChem · reference structure · [10] Drug Testing and Analysis · 2015 · [5] Journal of Peptide Research · 2000 · [2] Pharmeuropa Bio · 2004

02

Where it came from

In 1993, a group at Monash University in Australia synthesized growth hormone’s residues 177 to 191 and tested them on rat tissue. They concluded that one of the hormone’s actions on lipid synthesis is carried by this end of the chain.

The group then studied a version with a tyrosine added at the front, the peptide described here, publishing work in rats and mice from 2000. A 2004 drug-development profile reports early-phase clinical trials under way by 2002.

Sources: [3] Biochemistry and Molecular Biology International · 1993 · [4] Hormone Research · 2000 · [7] Endocrinology · 2001 · [8] Current Opinion in Investigational Drugs · 2004

03

A fragment, not the whole hormone

Growth hormone is a 191-amino-acid protein made by the pituitary gland, and it acts through its own receptor. The question was whether a small piece could carry one of its activities alone:

• Shape: a 2000 NMR study, which maps a molecule’s shape in solution, found the looped 15-residue fragment keeps some of the fold that stretch has inside the whole hormone.
• Receptor: in 2001 cell assays, the 16-residue peptide did not compete for the growth hormone receptor and, unlike the hormone, did not make receptor-carrying cells multiply.

and act further up the same axis, signaling the pituitary to release growth hormone; this peptide is a piece of the hormone itself. See What is ? and What is ?

Sources: [2] Pharmeuropa Bio · 2004 · [5] Journal of Peptide Research · 2000 · [6] Receptor and mouse studies · 2001

04

What researchers have studied

Its literature is mostly animal and laboratory work:

• Lipid metabolism in rats and mice (2000–2001): lipolysis, the breakdown of stored lipids, and energy use.
• Receptor pathways (2001): mice lacking the β3-adrenergic receptor, to test whether that receptor was required.
• Joint cartilage (2015): injections into rabbit knees, alone or with hyaluronic acid, after cartilage damage induced with an enzyme.
• Detection (2015): an anti-doping urine test, and a breakdown product in serum, the nine-residue CRSVEGSCG, that outlasts the intact peptide.

These are observations in laboratory models. They are not evidence about any use in people.

Sources: [4] Hormone Research · 2000 · [7] Endocrinology · 2001 · [6] Receptor and mouse studies · 2001 · [9] Annals of Clinical and Laboratory Science · 2015 · [10] Drug Testing and Analysis · 2015

05

How it is supplied and stored

ships as a lyophilized (freeze-dried) powder in 5 mg vials. The powder is stable at room temperature in transit. For lab use it is reconstituted with bacteriostatic water such as .

Concentration is content divided by volume: 5 mg in 2 mL gives 2.5 mg per mL. The reconstitution calculator handles other combinations.

For storage before and after reconstitution, see how to store lyophilized peptides.

06

How to verify a batch

Every lot has its own certificate of analysis from an independent lab. Read three results separately:

• Identity: confirms the expected compound was detected.
• Purity: the share of the measured material that is the intended compound.
• Content: the amount measured, compared with the label.

Then match the lot number on your vial or bottle to the report, and use the report’s verification link to confirm it with the testing lab. Step by step: how to read a peptide COA.