Three Analogs, One Axis

The short version

This page lines up CJC-1295, Sermorelin and Tesamorelin on the dimensions that matter most when reading research peptides: what kind of molecule each one is, where it has been studied, how strong that evidence is, how it was given in studies, its regulatory standing, and its single most important caution. All three bind the same GHRH receptor and stimulate the same GH/IGF-1 axis — but they differ substantially in structure, half-life and evidence depth. Tesamorelin has approved human RCT data for a specific indication; Sermorelin has an approved pediatric history and compounded-bulk status; CJC-1295 has human pharmacokinetic data but no approved indication. None is presented here with a human dose.

The comparison matrix

Peptide class

All three are GHRH analogs — synthetic peptides designed to bind the pituitary GHRH receptor and trigger GH secretion — but they represent three distinct approaches to the same design problem: how to make a durable, DPP-IV-resistant signal from a naturally fragile 44-residue hormone.

Sermorelin takes the minimalist path: just the first 29 residues of GHRH, amidated at the C-terminus, without additional modifications — the shortest piece that retains full receptor activity ^[10]. CJC-1295 adds four stabilizing substitutions to that same 29-residue template and, in its DAC form, a covalent albumin-tethering handle that extends half-life toward the lifespan of albumin itself ^[7]. Tesamorelin keeps the full 44 residues but adds only one modification — a trans-3-hexenoyl cap at the N-terminus that blocks DPP-IV at the cleavage site ^[1]. Three structural philosophies; one receptor target.

Most-studied in

Each compound has accumulated its deepest evidence in a different setting. CJC-1295 has been studied most in healthy adult pharmacokinetic work — characterizing the GH and IGF-1 dose-response, the half-life, and the preservation of pulsatility ^[4][5]. Sermorelin's deepest clinical record is in prepubertal children with GH deficiency, where it was studied in multicenter trials supporting the Geref NDA, with secondary editorial literature on its adult physiologic properties ^[11]. Tesamorelin's evidence base is the most clinically specific: multiple randomized controlled trials in HIV-infected adults with antiretroviral-related lipodystrophy, plus one class-level cognition RCT in older adults ^[8][12].

Evidence base (model)

This is where the three separate most clearly. Tesamorelin has the strongest human evidence by conventional drug-development standards — multiple RCTs pooled in a 2026 meta-analysis for its approved indication, and at least one cognition RCT at the class level ^[8][12]. Sermorelin has a human pediatric efficacy dataset behind its approved use, plus editorial literature on physiologic properties, but limited large-scale adult data ^[11][9]. CJC-1295 has human pharmacokinetic and pulsatility data in healthy volunteers ^[4][5], plus rat and in vitro mechanistic work ^[7] — but no clinical trials for any therapeutic indication and no regulatory approval ^[1].

Administration studied

All three are peptides that require subcutaneous injection in clinical and research use — oral and sublingual forms lack bioavailability. Sermorelin was studied and approved as a once-daily subcutaneous injection for the pediatric indication ^[11]. Tesamorelin's pivotal trials used once-daily subcutaneous dosing at 2 mg/day ^[14][16]. CJC-1295, particularly the DAC form, is the outlier: its extended half-life means the human PK studies used single and multiple doses separated by days to weeks rather than daily administration, and frequency of dosing was itself a study variable ^[4]. In GHRH-knockout mice, once-daily CJC-1295 normalized growth while every-48 or 72 hours was progressively less effective ^[6].

Regulatory and WADA status

The three occupy quite different positions on the regulatory spectrum. Tesamorelin holds an FDA approval (NDA 022505) for a specific HIV-associated lipodystrophy indication ^[13]; all other uses are off-label. Sermorelin was previously approved as Geref (NDA 020443) for pediatric GH deficiency, withdrawn in 2008 for commercial reasons, and is now a Category 1 bulk substance available through compounding pharmacies under the 503A interim policy ^[10]. CJC-1295 has no approved indication in any jurisdiction; it was reviewed (and not recommended for the 503A compounding bulks list) at the 2024 FDA Pharmacy Compounding Advisory Committee ^[1].

All three are prohibited in competitive sport under the WADA Prohibited List — CJC-1295 and tesamorelin as GHRH analogs under S2, and sermorelin under the same classification as a GH secretagogue ^[1][10].

Key caution

Each compound carries a defining caveat. For CJC-1295, it is that the human record is limited to pharmacokinetic studies with no clinical-indication evidence, combined with widespread conflation of the DAC (multi-day half-life) and no-DAC (short-acting) forms in community protocols ^[7]. For Sermorelin, it is the gap between its physiologic elegance and its evidence for adult wellness use: a leading editorial explicitly judged that use not yet ready for prime time, and that judgment has not been superseded ^[9]. For Tesamorelin, the defining caution is the contingency of effect on continued dosing — visceral fat reaccumulates within weeks of stopping — and the narrow scope of the approval, which does not transfer to off-label uses ^[16].

Read together, all three make the same point about GH-axis research: plausible mechanism, real pharmacological activity, and a human evidence base that thins quickly once you move away from the specific indication or population each compound was designed around.