Growth hormone releasing hormone.
Grossman. A A; Savage. M O MO; Besser. G M GM
Key Findings
- Exogenous GHRH (including analogues such as sermorelin) reliably raises circulating GH in many species, including humans.
- Continuous infusion of GHRH leads to a rapid decline in GH response, likely due to increased somatostatin activity.
- Obesity, elevated blood glucose, and high free fatty acids diminish the GH‑releasing effect of GHRH.
- Short‑term GHRH administration is safe, with only a minor increase in prolactin in most people.
- In GH‑deficient children, repeated GHRH injections can increase growth velocity.
Practical Outcomes
- For biohackers, the takeaway is to use GHRH analogues in short, intermittent bursts (e.g., a single injection before sleep) rather than continuous dosing to avoid desensitization. Timing the dose after an overnight fast or when insulin is low can improve the GH surge, and the effect may be weaker in overweight individuals. Monitor prolactin if you notice side effects, and set realistic expectations—GHRH can modestly raise GH but won’t replace a comprehensive health regimen.
Summary
GHRH (the natural hormone that tells the pituitary to release growth hormone) and its synthetic versions like sermorelin can safely boost GH levels when given in short, pulsed doses. The effect drops off if you give it continuously, and factors like excess body fat, high blood sugar, or free fatty acids can blunt the response. In kids with GH deficiency it can even speed growth, but in healthy adults it’s mainly a way to raise GH modestly.
Abstract
Human growth hormone releasing hormone (GHRH) was originally extracted from two pancreatic tumours in patients with acromegaly, and is now known to consist of a 44 residue amidated peptide or its C-terminal-shortened derivatives. The sequence of rat GHRH has also been determined; this 43 residue peptide shows approximately 70% homology with human GHRH, and is located mainly in the arcuate nucleus of the hypothalamus. Pulsatile GH release in the rat is principally a consequence of the pulsatile release of hypothalamic GHRH, although this appears to be associated with a transient suppression of somatostatin release. Exogenous GHRH specifically increases circulating GH in many species, and in the long term may increase growth. In normal man, several analogues of GHRH have been shown to be safe, sensitive and specific stimuli to GH release; although there may be a variable prolactin response, this is usually of small magnitude. Continuous infusion of GHRH leads to a decrement in responsiveness, due at least in part to changes in hypothalamic somatostatin. The GH response to GHRH is also modulated by obesity, blood sugar, free fatty acids, and GH itself. Many children with 'GH deficiency' (idiopathic, radiation-induced, or secondary to hypothalamopituitary tumours) respond to intravenous GHRH with an acute rise in serum GH. Early studies also indicate that long-term therapy with subcutaneous GHRH may increase growth velocity in some of these children. It is concluded that analogues of GHRH are useful in the investigation of the hypothalamopituitary axis, and may be important in the therapy of short stature.
Study Information
pubmed
1986
10.1016/s0300-595x(86)80012-3