Head to head
Sermorelin against Modified GRF 1-29
Modified GRF 1-29 is sermorelin with four amino acid substitutions intended to resist breakdown. Sermorelin was an approved medicine in the United States and is now supplied compounded; the modified version has never been evaluated by any regulator and has no located human trial.
Column A
SermorelinSermorelin (GHRH 1-29 analogue)
A GHRH fragment historically approved as a diagnostic and pediatric GH agent, now used in compounded anti-aging research.
Column B
Modified GRF 1-29Modified GRF 1-29, tetrasubstituted human growth hormone releasing factor 1-29
Sold as CJC-1295 without DAC, which is a contradiction: the DAC is what makes a molecule CJC-1295. The human trial everyone quotes, 2 to 10 fold higher growth hormone for 6 days or more with a half-life of 5.8 to 8.1 days, was run on the DAC form. No human trial of the version without the DAC has been located.
Side by side, on the facts we can check
| Attribute | Sermorelin | Modified GRF 1-29 |
|---|---|---|
| Category | Growth Hormone | Growth Hormone |
| FDA status | Previously FDA-approved (Geref, discontinued); available compounded | Not approved for any indication and not evaluated. Sermorelin, the unmodified GRF 1-29, was an approved medicine in the United States and is no longer marketed in its original form. Tesamorelin, a different GHRH analogue, is approved for HIV-associated lipodystrophy. |
| Half-life | ~10-20 minutes | Not measured in humans for this compound. For scale, native GRF 1-29 is cleared within minutes, while the albumin-bound DAC version was measured at about 6 days in healthy adults. |
| Molecular weight | 3,357.9 Da | About 3,368 Da for the tetrasubstituted 29 amino acid peptide without the DAC maleimide. |
| Mechanism | Activates pituitary GHRH receptors to stimulate physiological growth hormone release. | A growth hormone releasing hormone analogue acting at the GHRH receptor on anterior pituitary somatotrophs to trigger growth hormone release, which raises IGF-1 downstream. The tetrasubstitution of the native GRF 1-29 sequence resists dipeptidyl peptidase IV cleavage, extending the peptide's survival in plasma from minutes to somewhat longer, but it does not confer albumin binding. Release stays pulsatile and dependent on the pituitary's own capacity and on the opposing somatostatin tone, which is the practical difference between a secretagogue and injected growth hormone. |
| Human studies cited | 1 | 2 |
| Legal status, US | Prior approval discontinued; available via compounding pharmacies | Not approved; research use only |
Frequently asked questions
What is the difference between Sermorelin and Modified GRF 1-29?
Sermorelin: A GHRH fragment historically approved as a diagnostic and pediatric GH agent, now used in compounded anti-aging research. Modified GRF 1-29: Sold as CJC-1295 without DAC, which is a contradiction: the DAC is what makes a molecule CJC-1295. The human trial everyone quotes, 2 to 10 fold higher growth hormone for 6 days or more with a half-life of 5.8 to 8.1 days, was run on the DAC form. No human trial of the version without the DAC has been located.
Which has stronger research evidence, Sermorelin or Modified GRF 1-29?
This database does not grade compounds. It counts what was run in people: 1 of the 2 studies cited on the Sermorelin profile were human work, against 2 of 5 for Modified GRF 1-29. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are Sermorelin and Modified GRF 1-29 FDA-approved?
Sermorelin: Previously FDA-approved (Geref, discontinued); available compounded. Modified GRF 1-29: Not approved for any indication and not evaluated. Sermorelin, the unmodified GRF 1-29, was an approved medicine in the United States and is no longer marketed in its original form. Tesamorelin, a different GHRH analogue, is approved for HIV-associated lipodystrophy..
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Blog articles that cover Sermorelin or Modified GRF 1-29, newest first.
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.