Sermorelin vs Modified GRF 1-29
Written by Aaron CuhaReviewed Sep 2026
The short answer
Modified GRF 1-29 is sermorelin with four of its building blocks swapped to make it harder to break down. Sermorelin was an approved medicine in the United States and is now supplied by pharmacies that mix it. The modified version has never been reviewed by any regulator and has no human trial that anyone has found.
- Sermorelin people
- 139
- Sermorelin nulls
- 1
- Modified GRF 1-29 people
- 0
- Modified GRF 1-29 nulls
- 0
Dose
No human dose established
Amounts that circulate in forums and on vendor pages are not a human dose. Amounts that were given in studies sit in Human evidence on this page.
Commonly reported amounts, in mcg. The discontinued approved product was dosed by body weight, not as a fixed amount.
Amounts commonly reported by people buying Sermorelin, recorded for this archive's reconstitution calculator, are 100, 200, 300 and 500 mcg. They are self-reports rather than trial doses, and this archive does not recommend any of them. Sermorelin was an approved medicine and that label carried a dose; it is no longer marketed. These reported amounts are not that label's dose.
| Reported amount | Where the number comes from |
|---|---|
| 100 mcg | Commonly reported, no published human dosing trial |
| 200 mcg | Commonly reported, no published human dosing trial |
| 300 mcg | Commonly reported, no published human dosing trial |
| 500 mcg | Commonly reported, no published human dosing trial |
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
1 completed trial, 0 people given it
First-hand reports are counted on each profile and never added together. This page sets two published records side by side. It does not pick a winner.
Column A
SermorelinSermorelin (GHRH 1-29 analogue)
A piece of the hormone that tells your body to make growth hormone. It was once approved for children short on growth hormone. Now it is made by compounding pharmacies and used for anti-aging.
Column B
Modified GRF 1-29Modified GRF 1-29, tetrasubstituted human growth hormone releasing factor 1-29
Sold as "CJC-1295 without DAC", which makes no sense. The DAC is the part that makes a molecule CJC-1295. The human study everyone quotes found growth hormone 2 to 10 fold higher for 6 days or more, with half a dose cleared in 5.8 to 8.1 days. That study used the DAC form. No human study of the version without DAC has been found.
Side by side, on the facts we can check
| What we compare | Sermorelin | Modified GRF 1-29 |
|---|---|---|
| Category | Growth Hormone | Growth Hormone |
| FDA status | Previously FDA-approved (Geref, now discontinued); available made up by compounding pharmacies | Not approved for any use, and not reviewed. Sermorelin, the unchanged form of GRF 1-29, was an approved medicine in the United States. It is no longer sold in its original form. Tesamorelin, a different copy of the brain's growth hormone release signal (GHRH), is approved for the shifted body fat some people with HIV get. |
| 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. |
| How it works | It switches on the GHRH receptor in the pituitary gland. That makes the gland release growth hormone the normal way. | It copies growth hormone releasing hormone (GHRH). It presses the GHRH switch in the pituitary, the small gland under the brain. That tells the gland to release growth hormone, which then raises IGF-1, a growth signal made mostly in the liver. The four amino acid swaps protect it from DPP-4, the enzyme that breaks down the natural hormone. So it lasts somewhat longer in the blood than a few minutes. It does not stick to albumin. Growth hormone still comes out in bursts. How much comes out depends on your own pituitary, and on somatostatin, the body's brake on growth hormone. That is the real-life difference between a peptide that nudges your gland and a shot of growth hormone itself. |
| Studies in people | 3 | 2 |
| Evidence | Moderate: 3 completed trials, 139 people given it | Limited: 1 completed trial, none stating how many people |
| Legal status, US | Earlier approval discontinued; available from compounding pharmacies | Not approved; research use only |
Frequently asked questions
What is the difference between Sermorelin and Modified GRF 1-29?
Sermorelin: A piece of the hormone that tells your body to make growth hormone. It was once approved for children short on growth hormone. Now it is made by compounding pharmacies and used for anti-aging. Modified GRF 1-29: Sold as "CJC-1295 without DAC", which makes no sense. The DAC is the part that makes a molecule CJC-1295. The human study everyone quotes found growth hormone 2 to 10 fold higher for 6 days or more, with half a dose cleared in 5.8 to 8.1 days. That study used the DAC form. No human study of the version without DAC has been found.
Which has stronger research evidence, Sermorelin or Modified GRF 1-29?
Each compound gets a band worked out from facts we counted, with the math shown. Sermorelin is Moderate (3 completed trials, 139 people given it). Modified GRF 1-29 is Limited (1 completed trial, none stating how many people). That counts how much has been done in people. It does not rate whether either one works, and neither one is called the winner.
Are Sermorelin and Modified GRF 1-29 FDA-approved?
Sermorelin: Previously FDA-approved (Geref, now discontinued); available made up by compounding pharmacies. Modified GRF 1-29: Not approved for any use, and not reviewed. Sermorelin, the unchanged form of GRF 1-29, was an approved medicine in the United States. It is no longer sold in its original form. Tesamorelin, a different copy of the brain's growth hormone release signal (GHRH), is approved for the shifted body fat some people with HIV get..
Related posts
Blog articles that cover Sermorelin or Modified GRF 1-29, newest first.
Reviewed Sep 2026. This page puts two published records side by side. It is for learning, and it is not medical advice. When this site shows a dose, it is the dose a trial or a clinic actually used, or what people say they did, with the source attached. None of it tells you what to take.