CJC-1295 (without DAC) vs Tesamorelin

CJC-1295 (without DAC)

CJC-1295 without DAC, also called modified GRF (1-29), is a 29-residue synthetic analogue of growth hormone-releasing hormone (GHRH). Native GHRH has 44 residues, but its first 29 carry the receptor-binding activity, and this peptide is built on that shortened sequence with four amino-acid substitutions intended to slow breakdown. The name causes confusion: CJC-1295 originally referred to a version carrying a drug affinity complex (DAC), a reactive linker that binds albumin and greatly prolongs circulation. The form described here lacks that linker. Human studies of the DAC version exist but are few; published work on the form without DAC is thinner still, and much of what is said about it is inferred from the parent hormone.

Tesamorelin

Tesamorelin is a modified form of human growth hormone-releasing hormone (GHRH), keeping all 44 residues but altering the N-terminus. A trans-3-hexenoyl group is attached to the first residue, tyrosine, a change reported to shield the peptide from dipeptidyl peptidase-4, the enzyme that inactivates native GHRH within minutes. That distinguishes it from sermorelin, which keeps only the first 29 residues and carries no protecting group. Human clinical research has concentrated on HIV-associated lipodystrophy, a condition involving abnormal fat distribution, with smaller studies in other areas. Animal and cell work on the growth hormone axis sits alongside this, but outside the lipodystrophy setting, human data are limited.

How CJC-1295 (without DAC) acts

Like native GHRH, the peptide has been reported to bind the GHRH receptor, a class B G protein-coupled receptor on somatotroph cells of the anterior pituitary. Receptor activation couples to Gs, raising intracellular cAMP and releasing stored growth hormone; circulating growth hormone in turn drives IGF-1 production, mainly in the liver. The substitutions, D-alanine at position 2, glutamine at 8, alanine at 15 and leucine at 27, were chosen to resist cleavage by dipeptidyl peptidase-4 and to reduce deamidation and oxidation at vulnerable residues. Without the albumin-binding linker its half-life is short, and pharmacokinetic data specific to this form are sparse.

How Tesamorelin acts

Tesamorelin binds the GHRH receptor on somatotroph cells of the anterior pituitary, the class B G-protein-coupled receptor also targeted by native GHRH and sermorelin. Receptor activation raises cyclic AMP and has been reported to increase both synthesis and release of growth hormone, which keeps a pulsatile pattern because somatostatin and IGF-1 feedback still operate. Circulating growth hormone in turn drives IGF-1 production, mostly in the liver. Studies of adipose tissue have examined the lipolytic action of growth hormone as one link in this pathway, though the separate roles of growth hormone and IGF-1 are not fully resolved.

The records side by side

• Type: CJC-1295 (without DAC), GHRH analog (Modified GRF 1-29); Tesamorelin, GHRH analog (growth hormone secretagogue)
• Length: CJC-1295 (without DAC), not recorded; Tesamorelin, 44 amino acids
• Molecular weight: CJC-1295 (without DAC), 3647.2 g/mol; Tesamorelin, 5136 g/mol
• Molecular formula: CJC-1295 (without DAC), C165H269N47O46; Tesamorelin, C221H366N72O67S
• Half-life: CJC-1295 (without DAC), not recorded; Tesamorelin, Mean elimination half-life (T1/2) of tesamorelin was 26 and 38 minutes in healthy subjects and HIV-infected patients, respectively, after subcutaneous administration for 14 consecutive days." (original EGRIFTA label, 2010). By contrast t…

Reading a comparison

A comparison places two records side by side; it does not merge them. Each description above is drawn from that compound's own record, and the two were not necessarily characterised by the same methods, at the same time, or to the same level of detail. Before comparing any attribute, it is worth establishing that both records describe the substance you think they describe — names are not identifiers, and two entries sharing a name can differ in salt form, stereochemistry or the convention used to state a mass. Where a figure carries no method beside it, the comparison is between two reported numbers rather than between two measurements.