After forty the night-time pulses of growth hormone get lower and the IGF-1 level falls with them, a change the scales do not show. That is why the secretagogue group is the most frequently bought category in this age range. Below is what happens to the growth hormone axis over the years, what was measured in studies on raising it, and which molecules in the catalogue belong to this group.
What happens to the growth hormone axis
Growth hormone is released by the pituitary, mainly at night, in several pulses a day. Under its influence the liver produces IGF-1, insulin-like growth factor, which accounts for most of the axis's action in the tissues. With age both the height of the night-time pulses and the IGF-1 level fall. Reviews of how this axis ages describe it, among them one in Experimental Gerontology from 2015.
The entry criterion of a 1990 study shows the scale of this decline well. The New England Journal of Medicine paper took healthy men aged 61 to 81. The condition for entry was an IGF-1 level below 350 units per litre. The typical range for young people there runs from 500 to 1500 units. Finding older men below the threshold was not a problem.
What was measured when the axis was raised
In the same study twelve men received growth hormone for six months, and nine received nothing. In the treated group lean mass rose by 8.8 per cent. Fat mass fell by 14.4 per cent, and lumbar spine density rose by 1.6 per cent. Skin thickness increased by 7.1 per cent. That last change did not reach significance. In the untreated group nothing changed.
The second study concerned a secretagogue, a molecule that stimulates the body's own growth hormone release. In 2009 the Journal of Clinical Endocrinology and Metabolism described a study of 395 people aged 65 to 84. After six months body weight in the active group rose by 1.4 kg. In the placebo group it fell by 0.2 kg. Lean mass rose by 1.4 kg against 0.3 kg, and tandem walk time improved by 0.9 seconds. The authors also recorded fatigue and insomnia. Fasting glucose and glycated haemoglobin rose as well.
Why sleep is a separate topic here
The largest daily growth hormone release falls in the first hours of deep sleep. That is why with peptides from this group not only hormones but also EEG recordings are measured. Five sleep studies on molecules from this family are compared in the guide to growth hormone peptides and sleep. The differences between the families themselves are set out in the guide to growth hormone peptides.
Which molecules in the catalogue belong to this group
| Molecule | Family | Price from |
|---|---|---|
| Sermorelin | GHRH analogue | 40 EUR for 5 mg |
| Mod GRF 1-29 | GHRH analogue | 35 EUR for 10 mg |
| CJC-1295 | GHRH analogue | 25 EUR for 5 mg |
| Tesamorelin | GHRH analogue approved as a medicine | 50 EUR for 10 mg |
| Ipamorelin | GHS-R1a secretagogue | 40 EUR for 10 mg |
| GHRP-2 | GHS-R1a secretagogue | 20 EUR for 10 mg |
| GHRP-6 | GHS-R1a secretagogue | 20 EUR for 10 mg |
| Hexarelin | GHS-R1a secretagogue | 45 EUR for 10 mg |
The two families stimulate the pituitary from two different sides, so in practice one molecule from each is combined. The most popular pair is CJC-1295 with ipamorelin. The reasons for that choice are set out in a separate guide to combining this pair. The ready-made blend of both in one vial is on the CJC-1295 and ipamorelin page.
What you can measure yourself
IGF-1 is measured in an ordinary laboratory from a single blood draw, so it is a measure available outside a research study. Alongside it, it is worth recording waist circumference, body weight and sleep quality, always at the same rhythm. How to keep such measurements is described in the guide to how to measure peptide results.
Where these data end
The studies described concern growth hormone and a secretagogue studied as a medicine, given under controlled conditions. The peptides in the catalogue are sold as material for laboratory research and have no such human studies. The figures from these papers describe the mechanism and the way of measuring, not a promised result. The status of each molecule is explained in the guide to the legal status of peptides. Prices for the whole range are on the price list.
Frequently asked questions
Why is this group of peptides talked about after forty?
Because with age the night-time growth hormone pulses and the IGF-1 level fall, and secretagogues target exactly this axis.
What did the 1990 study show?
After six months lean mass rose by 8.8 per cent, and fat mass fell by 14.4 per cent.
How do the two secretagogue families differ?
GHRH analogues act through the releasing hormone receptor, while GHRP molecules act through the GHS-R1a receptor.
Which pair is chosen most often?
CJC-1295 with ipamorelin, also available as a ready-made blend in one vial.
What should I measure to see a change?
IGF-1 from blood, waist circumference and body weight, at a steady rhythm every few weeks.
Sources
- Ashpole NM, Sanders JE, Hodges EL et al. Growth hormone, insulin-like growth factor-1 and the aging brain. Experimental Gerontology, 2015, 68: 76-81. https://doi.org/10.1016/j.exger.2014.10.002
- Rudman D, Feller AG, Nagraj HS et al. Effects of human growth hormone in men over 60 years old. New England Journal of Medicine, 1990, 323(1): 1-6. https://doi.org/10.1056/NEJM199007053230101
- White HK, Petrie CD, Landschulz W et al. Effects of an oral growth hormone secretagogue in older adults. Journal of Clinical Endocrinology and Metabolism, 2009, 94(4): 1198-1206. https://doi.org/10.1210/jc.2008-0632