Sermorelin: research background and regulatory history

What sermorelin is

Sermorelin is a synthetic analogue of growth hormone-releasing hormone, consisting of the first 29 amino acids of endogenous GHRH with a C-terminal amide. That fragment is the shortest portion of GHRH retaining the full biological activity of the parent hormone, which is why it became the basis for a pharmaceutical product.

The Geref history

Geref was used both as a diagnostic agent for assessing pituitary growth hormone secretory capacity, and later in a paediatric indication relating to growth hormone deficiency.

It was discontinued from the United States market in 2008. The discontinuation is widely documented as a commercial decision rather than a safety withdrawal — recombinant growth hormone had become the dominant approach, and the market for a GHRH analogue narrowed accordingly.

This distinction is worth stating precisely, because “no longer marketed” and “withdrawn for safety” mean very different things and are frequently conflated.

Research background

Because sermorelin went through pharmaceutical development, the literature on it is different in character from the rest of this catalogue — it includes controlled clinical work rather than being predominantly preclinical.

Published research has covered:

• its use as a diagnostic probe of pituitary responsiveness;
• pharmacokinetic and pharmacodynamic characterisation in humans;
• paediatric growth hormone deficiency, in the context of its approved indication;
• comparative work against direct growth hormone administration.

A structural point that recurs in the literature: because sermorelin acts upstream, at the level of GHRH signalling, the response it produces remains subject to the body’s own regulatory feedback in a way that direct hormone administration does not.

Where it sits in its class

Compounds discussed as “growth hormone secretagogues” fall into two mechanistically distinct groups: GHRH analogues such as sermorelin, and ghrelin-receptor agonists, which act through a different receptor entirely.

They are frequently grouped together in commercial contexts despite not sharing a mechanism. The comparison page covers this, including an explanation of which compounds in this class we have deliberately chosen not to stock and why.

Regulatory context

• Formerly approved. Approved by the FDA and marketed as Geref; discontinued in the United States in 2008 for commercial reasons.
• Not currently marketed as a drug in the US. There is no current FDA-approved sermorelin product on the US market.
• Prohibited in sport. Listed by the World Anti-Doping Agency under growth hormone releasing factors.
• Sold as a research chemical. Supplied for laboratory research use only.