Search any research peptide catalog and a large share of the growth-hormone-related compounds fall into a family that confuses newcomers because the names give no hint of how they relate. Sermorelin, tesamorelin, CJC-1295, ipamorelin, GHRP-6, and others all touch the growth hormone axis, but they split cleanly into two groups once you know the organizing principle. This article is a map of that family.
Two pathways, one axis
The body regulates growth hormone release through two distinct signals that converge on the same cells in the pituitary. The first is growth hormone-releasing hormone (GHRH), which acts on the GHRH receptor. The second is ghrelin, which acts on a separate receptor, the growth hormone secretagogue receptor. Because these are two different receptors, research peptides are designed to mimic one or the other, and that is the single distinction that organizes the entire family. Every compound below is either a GHRH-side analogue or a ghrelin-receptor-side secretagogue.
The GHRH-analogue side
These peptides are structural analogues of GHRH and act on the GHRH receptor.
Sermorelin is GHRH(1-29), the reference fragment, the shortest sequence that retains the parent hormone’s core activity. It is the natural starting point for understanding the group, and our sermorelin overview covers it in depth.
Modified GRF (1-29), commonly sold as CJC-1295 no DAC, is a stabilized version of that same fragment. CJC-1295 with DAC adds the Drug Affinity Complex modification for a much longer active window. The CJC-1295 overview explains the DAC distinction.
Tesamorelin is another stabilized GHRH analogue, studied for its own structural modifications. See the tesamorelin overview.
The ghrelin-receptor side
These peptides act on the growth hormone secretagogue receptor, the ghrelin pathway, not the GHRH receptor.
Ipamorelin is a selective pentapeptide secretagogue, valued in the literature for engaging the ghrelin receptor without the broader activity of earlier compounds. The ipamorelin overview covers its selectivity.
GHRP-6 is an earlier growth hormone-releasing peptide from the same receptor side, studied before more selective options existed.
Why the two-pathway map matters
The reason this map is useful, rather than trivia, is that the two pathways are frequently studied together. Because a GHRH-side analogue and a ghrelin-side secretagogue act on different receptors, they are natural experimental pairs, and combinations such as CJC-1295 no DAC with ipamorelin appear precisely because they hit the two pathways at once. Our CJC-1295 and ipamorelin blend overview is the worked example. Knowing which side of the axis a compound sits on tells you immediately whether two peptides are redundant or complementary.
Verification applies across the whole family
Every compound in this family is verified the same way, and several of them are structurally close enough that identity testing earns its keep. Sermorelin, Modified GRF, and the CJC-1295 forms are all variations on the GHRH(1-29) sequence, which means mass spectrometry is what distinguishes them from one another. Purity comes from high-performance liquid chromatography. Our guide to reading a certificate of analysis applies to every peptide on this map.
The bottom line
The growth hormone peptide family is not a long list to memorize; it is two pathways. GHRH-side analogues (sermorelin, Modified GRF, CJC-1295, tesamorelin) act on the GHRH receptor. Ghrelin-side secretagogues (ipamorelin, GHRP-6) act on the growth hormone secretagogue receptor. Once a compound is placed on the correct side, its relationship to every other compound in the family becomes clear, and so does why certain pairs are studied together.
Heartland Bio Labs supplies these peptides strictly for laboratory research use. Nothing in this article is guidance for human or veterinary use of any compound.
Research compounds in this article
For research use only. Not for human consumption. Every product ships with a published certificate of analysis.