Modified GRF (1-29) serves as a peptide analogue derived
from growth-hormone-releasing hormone (GHRH). Its
development in the 1980s stemmed from the revelation
that the initial 29 amino acids of GHRH preserved all
characteristics of the complete 44-amino-acid protein. The
original protein, GRF (1-29), represents the smallest
fragment of GHRH maintaining its entire functionality.
Another abbreviated synthetic variation, known as
Sermorelin or GRF 1-29, comprises 29 amino acids,
whereas Modified GRF (1-29) undergoes further
modifications by substituting four amino acids within its
chain. These substitutions are aimed at preventing
degradation and oxidation during manufacturing,
transportation, and within the body, concurrently
enhancing its affinity to bind with GHRH receptors.
While GRF exhibited full efficacy, its short half-life (less
than 10 minutes) limited its duration of action.
Consequently, researchers modified GRF (1-29) to extend
its half-life, thus amplifying its therapeutic potential.
Occasional references to Modified GRF (1-29) include
terms like mod GRF or tetrasubstituted GRF (1-29),
emphasizing the distinction from GRF (1-29) due to the
alteration of four amino acids. Notably, Modified GRF (1-
29) mirrors CJC-1295 without DAC in its composition.