Tesamorelin vs CJC-1295: What Research Shows
Tesamorelin and CJC-1295 are both synthetic analogs of growth hormone-releasing hormone (GHRH). They are often treated as interchangeable. The studies do not support that. Both can signal through the GHRH receptor on pituitary somatotrophs, but half-life, the shape of the growth hormone (GH) signal, the human evidence, and regulatory status differ. This page is a research reference only. It is not a protocol and not guidance for human use.
Two GHRH analogs, two designs
Tesamorelin (TH9507) is a 44-amino-acid analog of human GHRH. A trans-3-hexenoyl group on the first tyrosine slows cleavage by dipeptidyl peptidase IV, so the peptide outlasts native GHRH, which is cleared in minutes. Prescription products based on this sequence were studied for one indication: reduction of excess abdominal fat in HIV-associated lipodystrophy. That license does not turn a research-supply vial into the approved drug, and it does not extend the finding to general fat loss. Mechanism detail is on the page about what tesamorelin does.
CJC-1295 starts from modified GRF(1-29), with amino-acid substitutions that also resist enzymatic breakdown. The name covers two materials. CJC-1295 with Drug Affinity Complex (DAC) adds a lysine linked to maleimidopropionic acid. After injection that group binds albumin, and the half-life stretches into days. CJC-1295 without DAC is the same modified GRF(1-29), often labeled Mod GRF 1-29, and it clears in about half an hour. What is true of what CJC-1295 does depends on which sequence is in the vial. The CJC-1295 protocol page keeps the forms separate.
Half-life and the shape of the GH signal
Published pharmacokinetics put the mean half-life of tesamorelin near 26 minutes in healthy adults and near 38 minutes in HIV-infected patients. A once-daily subcutaneous injection still leaves room for pulsatile GH release, followed by a hepatic IGF-1 rise. The original Egrifta program used 2 mg once daily. Egrifta SV is labeled at 1.4 mg once daily. Those are prescription-label figures, not dosing advice for research material. Published ranges are collected on the tesamorelin dosage page.
CJC-1295 with DAC is a different kinetic object. In the 2006 Teichman study in healthy adults, single subcutaneous doses from 30 to 250 mcg/kg raised GH for about a week and lifted IGF-1 to roughly 1.5 to 3 times baseline, with that elevation lasting more than a week after one dose. The estimated half-life was about 6 to 8 days. That pattern is a raised baseline, not a brief pulse.
CJC-1295 without DAC clears in about 30 minutes. Designs that want a pulse give it once or several times a day, often with ipamorelin, so two receptors can amplify one burst. That pairing is separate from tesamorelin used alone. Figures for the pair are on the CJC-1295 and ipamorelin dosage page.
| Feature | Tesamorelin | CJC-1295 with DAC | CJC-1295 no DAC |
|---|---|---|---|
| Backbone | GHRH(1-44), N-hexenoyl | Modified GRF(1-29) plus DAC | Mod GRF 1-29, no DAC |
| Reported half-life | About 26 to 38 minutes | About 6 to 8 days | About 30 minutes |
| GH pattern in research | Daily pulse, then an IGF-1 rise | Sustained GH and IGF-1 elevation | Short pulse, often paired with a GHRP |
| Human evidence | RCTs on visceral fat in HIV lipodystrophy | Pharmacokinetic and endocrine studies | Little controlled outcome data |
| Regulatory status | Approved drug for one HIV indication | Not approved. Outcome program halted | Not approved |
Every figure in that table is research-reported or taken from a published label. None of it is a dose to copy, and none of it is instructions for human administration.
What the human studies actually measured
Tesamorelin has randomized, placebo-controlled trials with a body-composition endpoint. In HIV lipodystrophy, about 26 weeks of daily treatment reduced visceral adipose tissue on the order of 15 percent from baseline, with little change in subcutaneous fat or scale weight. After treatment stopped, that visceral change largely returned. IGF-1 rose and was tracked as a safety lab.
CJC-1295 with DAC has human pharmacokinetic data, not a visceral-fat outcome program. A long-acting GHRH analog can hold IGF-1 above baseline for days after one injection. That is not the tesamorelin lipodystrophy result. A clinical program stopped in 2006 after a death during a study. Causation was not established, and large outcome trials were not finished. Muscle and fat-loss claims for either CJC form rest on GH physiology and uncontrolled reports.
Side effects are not one shared list
Reported class effects include injection-site reactions, flushing, headache, fluid retention, joint pain, and tingling. Tesamorelin trials also describe arthralgia, extremity pain, and peripheral edema, with caution where malignancy is active or glucose control is fragile. CJC-1295 data are thinner. With DAC, IGF-1 can stay high for days, so a nighttime pulse is replaced by a higher baseline. Whether that pattern carries a different long-term risk is unsettled. The no-DAC form has even less controlled safety data.
They answer different research questions
Controlled visceral-fat data in HIV lipodystrophy belong to tesamorelin. A multi-day IGF-1 rise after one injection belongs to CJC-1295 with DAC. A short GHRH pulse beside a ghrelin mimetic belongs to CJC-1295 without DAC. Using the names as synonyms, because both are GHRH analogs, drops those differences.
Either research vial still needs a known identity, purity, and concentration before an exposure figure means anything. A calculator converts milligrams and milliliters. It does not choose a compound, and it does not turn a research reagent into a medicine.