Tesamorelin vs Sermorelin: what is the difference?

01

At a glance

The main differences in one list:

• Length: all 44 amino acids of GHRH for Tesamorelin; the first 29 for Sermorelin.
• Added group: a trans-3-hexenoyl chain on the first amino acid of Tesamorelin; none on Sermorelin.
• Reference formula: C221H366N72O67S (about 5,136 g/mol) versus C149H246N44O42S (about 3,358 g/mol).
• Stability: the plasma enzyme DPP-IV cuts the start of Sermorelin; Tesamorelin resisted it in a 2007 study.
• Formats at Prism Labs: both as 10 mg lyophilized vials.

Sources: [2] PubChem · reference structure · [1] PubChem · reference structure · [4] Journal of Clinical Investigation · 1989 · [5] Basic & Clinical Pharmacology & Toxicology · 2007

02

What they share

Both copy the same stretch of the natural hormone: the 29 amino acids of Sermorelin are also the first 29 of Tesamorelin, which continues for 15 more.

Both end in an amide, like the natural hormone, and both were among four GHRH analogues in a 2021 anti-doping study.

Sources: [1] PubChem · reference structure · [2] PubChem · reference structure · [5] Basic & Clinical Pharmacology & Toxicology · 2007 · [7] Drug Testing and Analysis · 2021

03

Length versus protection

The natural hormone breaks down quickly in blood. A 1989 study traced the main cut to the enzyme dipeptidyl peptidase IV (DPP-IV), which splits the chain between its second and third amino acids, and found the same cut in the 1–29 amide.

Sermorelin is the hormone made shorter, not sturdier: in 1984 rat pituitary-cell experiments it kept about half the full hormone’s potency, but nothing protects its first two amino acids.

Tesamorelin keeps the full length and protects the start: in a 2007 preclinical paper, its hexenoyl group resisted DPP-IV and slowed breakdown in rat, dog and human plasma. Even so, its half-life in dogs was 21 to 45 minutes.

Sources: [4] Journal of Clinical Investigation · 1989 · [3] Biochemical and Biophysical Research Communications · 1984 · [5] Basic & Clinical Pharmacology & Toxicology · 2007

04

Where CJC-1295 and Ipamorelin fit

CJC-1295 took a third route: the 1–29 sequence with four amino acids substituted. The 2005 paper that introduced it also added an albumin-binding group, which kept it in rat plasma beyond 72 hours. Versions with and without this group, called DAC, are separate compounds.

Ipamorelin is not a GHRH analogue. A 1998 study showed that this five-residue peptide works through a different receptor; in 1999 that receptor’s natural ligand was identified as ghrelin, a peptide from the stomach.

The blend CJC / Ipamorelin (No DAC) pairs one of each: CJC-1295 without DAC and Ipamorelin.

Sources: [6] Endocrinology · 2005 · [7] Drug Testing and Analysis · 2021 · [8] European Journal of Endocrinology · 1998 · [9] Nature · 1999

05

How their research differs

Their literatures overlap less than their sequences:

• Sermorelin: 1980s structure–activity work in rat pituitary cells, and where plasma enzymes cut it.
• Tesamorelin: plasma stability and repeat-dose studies in rats, dogs and pigs (2007), then clinical studies covered in its profile.
• Both: urine detection methods (2021).

These are observations in laboratory models. They are not evidence about any use in people.

Sources: [3] Biochemical and Biophysical Research Communications · 1984 · [4] Journal of Clinical Investigation · 1989 · [5] Basic & Clinical Pharmacology & Toxicology · 2007 · [7] Drug Testing and Analysis · 2021

06

Formats and full profiles

Both ship as 10 mg lyophilized vials, reconstituted with bacteriostatic water such as Prism H2O. Each lot has its own certificate of analysis: how to read a peptide COA.

Full profiles: What is Tesamorelin? and What is Sermorelin?

The secretagogue on its own: What is Ipamorelin?