Sermorelin Side Effects: What the Trials Reported

How common are injection-site reactions?

This is the effect reported most often. In the large childhood trial, three of the sixty children had mild irritation where the shot went in. A drug review from the market years lists the same thing as the main local complaint. It tends to be soreness, redness, or a little swelling, not a lasting problem.

A long-acting look-alike had injection-site reactions more often than placebo, but even there they were mild and brief. That is a different molecule, covered further down.

Sources: Chen and colleagues, 1993 in Acta Paediatr Suppl, a randomised trial in 60 growth-deficient children. Antibodies to the peptide appeared in 39 of 40 and faded after treatment stopped. PMID 8329830; Prakash and Goa, 1999 in BioDrugs, a drug review from when sermorelin was still sold; it describes brief facial flushing and good tolerance. PMID 18031173; Munafo and colleagues, 2005 in Eur J Endocrinol, a long-acting PEG analogue, not sermorelin; mild brief injection-site reactions and some glucose-handling trouble in elders, no antibodies. PMID 16061831

Does sermorelin cause facial flushing?

It can, but mainly at higher amounts given into a vein. In a small study of five healthy men, the only side effect noted was brief flushing, and only at the top amount tested. No other hormone and no glucose measure moved. The drug review from the market years describes the same short flushing.

Flushing in these studies came and went quickly. Nothing in the record points to a lasting skin or blood-pressure problem from it.

Sources: Barron and colleagues, 1985 in Peptides, an intravenous study in 5 healthy men that saw brief flushing only at the top dose and no change in other hormones or glucose. PMID 2866496; Prakash and Goa, 1999 in BioDrugs, a drug review from when sermorelin was still sold; it describes brief facial flushing and good tolerance. PMID 18031173

Why did children grow antibodies to sermorelin?

This is the finding the clinic pages skip. In a randomised childhood trial, 39 of 40 children on the peptide developed antibodies to it over six months. The antibodies did not change how well the children grew, and they had almost disappeared nine months after treatment stopped. A smaller study saw fewer, with antibodies in 4 to 6 of 11 responders, again without blocking growth.

So the antibodies were common but reversible and, in that trial, harmless to growth. It is still worth knowing, because repeated dosing of a peptide can trigger this kind of immune response.

Sources: Chen and colleagues, 1993 in Acta Paediatr Suppl, a randomised trial in 60 growth-deficient children. Antibodies to the peptide appeared in 39 of 40 and faded after treatment stopped. PMID 8329830; Lanes and Carrillo, 1994 in J Pediatr Endocrinol, a childhood study in which antibodies appeared in 4 to 6 of 11 responders and did not block growth. PMID 7735367

Does the effect wear off over time?

With nonstop dosing, yes. When children were given the peptide as a continuous infusion for six months, the growth-hormone burst it caused shrank by three to six months. The response simply faded as the steady exposure continued.

In another childhood study, growth slipped back to its old rate once treatment stopped. The effect did not carry on after the shots ended. These are observations about the growth-hormone response, not claims about any body-shape result.

Sources: Tauber and colleagues, 1993 in Acta Paediatr Suppl, a 6 month nonstop infusion in 6 children; the growth-hormone response fell away by 3 to 6 months. PMID 8329829; Brain and colleagues, 1990 in Clin Endocrinol, in which growth went back to its old rate once treatment stopped. PMID 2140733

What did the adult trials not test for?

The adult studies were short and small. In one, eleven older men took the peptide for six weeks with no significant adverse effects and no change in IGF-I or body-scan muscle and fat. In another, older men showed no change in fasting glucose or blood pressure. That is reassuring for a few weeks, but it is a narrow window.

• No adult study ran long enough to weigh heart health, cancer risk, or safety across years.
• No serious event was reported, but the trials were too small and short to catch rare harms.
• With no approved label, there is also no official warning list to measure against.

In short, the trials found little, and they also looked for little. For the full study record, see the sermorelin dosage chart.

Sources: Vittone and colleagues, 1997 in Metabolism, a 6 week study in 11 healthy older men that reported no significant adverse effects and no change in IGF-I or body scans. PMID 9005976; Corpas and colleagues, 1992 in J Clin Endocrinol Metab, a 14 day study in older men with no change in fasting glucose or blood pressure. PMID 1379256

Which side effects belong to look-alikes, not sermorelin?

Two effects often pinned on sermorelin came from different molecules. A study of an engineered analogue reported brief high blood fats as its only side effect. A separate long-acting PEG version caused some glucose-handling trouble in older people. Neither drug was plain sermorelin.

This matters because much of the research sold online as sermorelin data is really about these longer-acting cousins. Our tesamorelin vs sermorelin guide explains how the molecules differ.

Sources: Khorram and colleagues, 1997 in J Clin Endocrinol Metab, which tested an engineered analogue, not plain sermorelin; its only side effect was brief high blood fats. PMID 9141536; Munafo and colleagues, 2005 in Eur J Endocrinol, a long-acting PEG analogue, not sermorelin; mild brief injection-site reactions and some glucose-handling trouble in elders, no antibodies. PMID 16061831

What about headaches, water retention and joint pain?

Many clinic pages list headache, dizziness, water retention, joint pain, or high IGF-1. None of those showed up as a sermorelin finding in the trials gathered here. Some are known effects of growth hormone itself, which is a different treatment, and some are simply general cautions.

We leave them off the trial list on purpose. Reporting an effect the studies did not find would be guessing, and this page sticks to what the record shows.

Sources: Prakash and Goa, 1999 in BioDrugs, a drug review from when sermorelin was still sold; it describes brief facial flushing and good tolerance. PMID 18031173; Vittone and colleagues, 1997 in Metabolism, a 6 week study in 11 healthy older men that reported no significant adverse effects and no change in IGF-I or body scans. PMID 9005976

What happened to the Geref brand?

Sermorelin was once sold as Geref. Its maker stopped making it, and the approval was withdrawn in 2009. A 2013 FDA notice is clear that the pull had nothing to do with safety or with how well the drug worked. Because the old label was never posted online, there is no official side-effect sheet to quote, which is why this page leans on the trials instead.

Sources: US FDA, Federal Register, 4 March 2013. States that Geref (sermorelin acetate) injection was pulled from sale, and that the reason was not about safety or how well it worked.

Common questions

Sources: Vittone and colleagues, 1997 in Metabolism, a 6 week study in 11 healthy older men that reported no significant adverse effects and no change in IGF-I or body scans. PMID 9005976; Corpas and colleagues, 1992 in J Clin Endocrinol Metab, a 14 day study in older men with no change in fasting glucose or blood pressure. PMID 1379256; US FDA, Federal Register, 4 March 2013. States that Geref (sermorelin acetate) injection was pulled from sale, and that the reason was not about safety or how well it worked.