Sermorelin

Growth hormone-releasing hormone, or GHRH, is the natural cue the body sends to prompt the pituitary gland into releasing growth hormone, and Sermorelin, built in a lab from 29 amino acids, copies the working part of that signal. It was once an FDA-approved medicine for a specific pediatric condition, but the maker pulled it from the market in 2008 over manufacturing issues, not safety; even so, growth-hormone researchers have examined it more closely than most other peptides in the field.

What it is

The pituitary gland, a small gland at the base of the brain, releases growth hormone in short pulses across the day whenever GHRH tells it to. Sermorelin reproduces amino acids 1 through 29 of that natural hormone, the stretch researchers found sufficient to trigger the same signal.

Because it prompts the pituitary's own release mechanism rather than supplying growth hormone directly, researchers describe sermorelin as preserving the body's natural pulsing pattern of hormone release, in contrast to giving growth hormone itself as a steady, externally controlled amount.

How it is studied

Sermorelin's research base includes the human trials that supported its original FDA approval in prepubertal children with growth hormone deficiency, along with separate human studies on nasal delivery and combination effects with other growth-hormone-releasing compounds.

What studies report

A small study of nasal delivery in children with short stature found that a single amount sprayed into the nose caused a prompt rise in growth hormone within 15 minutes that stayed raised for at least 2 hours, with no side effects except mild nasal burning in one child. [1]
In healthy adult volunteers given single doses, sermorelin (GHRH 1-29) alone produced a modest rise in growth hormone, a separate growth-hormone-releasing peptide (GHRP-2) alone produced a much larger rise, and the two combined produced the largest rise of all; however, the researchers could not statistically confirm that the combination worked better than simply adding the two separate effects together, so true synergy between them was not established in this study. [2]
In the pivotal 1-year trial supporting its original approval, 110 children with diagnosed growth hormone deficiency who had not been treated before were given a once-daily injection under the skin; growth speed rose from about 4.1 centimeters per year at the start to 8.0 after 6 months, easing slightly to 7.2 after 12 months, with about 74 percent of children counted as good responders at 6 months and no adverse changes in blood chemistry. [3]

What is not known

Because the maker withdrew sermorelin's approved product in 2008 over manufacturing problems rather than a safety finding, and it is now supplied only through compounding pharmacies, there has been no equivalent large-scale, regulator-reviewed trial program since that time. The pivotal trial that supported its approval followed children for only 1 year, and growth speed had already eased somewhat by the 12-month mark compared with the 6-month peak, so longer-term comparative data beyond that window is not established in the sources reviewed.

Reported adverse findings

Growth-hormone research of this kind has been associated with a change in thyroid hormone levels in some patients, which is one reason ongoing hormone monitoring is part of studies in this area. [3]

Regulatory status

In 1997 the FDA approved Sermorelin, marketed as Geref, to treat children with growth hormone deficiency, but the maker pulled that product from the market in 2008 over manufacturing problems, not a safety concern. It is no longer FDA-approved and is currently supplied only through compounding pharmacies, a different and less strictly reviewed regulatory pathway than an approved drug.