Short answer: No human studies together; GH-raising drugs can raise blood sugar while retatrutide lowers it.
- FlagCaution
- EvidenceMechanism only
- Sources3
- Last reviewedOctober 22, 2026
What is known
No human studies of these two together were found. CJC-1295 raises growth hormone, and the growth hormone (somatropin) label says GH can lower insulin sensitivity and unmask high blood sugar or diabetes. Retatrutide lowers blood sugar. The two push glucose in opposite directions, so blood sugar may be harder to predict; this is a theoretical concern, not a measured one.
CJC-1295 raised GH and IGF-1 for 6 or more days after one dose in healthy adults. Retatrutide improved blood sugar control in a phase 3 trial in people with obesity and type 2 diabetes. People with diabetes or on other glucose-lowering drugs have the most reason to track glucose.
How strong the evidence is
Mechanism only. Theoretical. No study tested the pair; the concern comes from documented effects of each compound on its own. Caution: There is a documented or likely risk to watch for, such as low blood sugar or added side effects. Talk to your prescriber before combining.
Guides: Retatrutide, CJC-1295. To check this pair alongside others, open it in the peptide interaction checker.
Education only, not medical advice. "No known interaction" means we found nothing reported, not that a combination is safe. Most of the peptides here are not FDA approved, and most pairs have never been studied together in people. Talk to your clinician or pharmacist before you start, stop or combine anything.
Sources
- Teichman SL, et al. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. J Clin Endocrinol Metab, 2006. PMID 16352683
CJC-1295, a long-acting GHRH analog, raised GH 2- to 10-fold for 6+ days and IGF-1 1.5- to 3-fold for 9-11 days after one injection in healthy adults; half-life 5.8-8.1 days.
- GENOTROPIN (somatropin) kit - Prescribing Information. FDA label (DailyMed), 2026
Somatropin label: GH may decrease insulin sensitivity, can unmask impaired glucose tolerance or diabetes; monitor glucose.
- Bellido V, et al. Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2): a double-blind, parallel-group, randomised, placebo-controlled, phase 3 trial. Lancet, 2026. PMID 42810372
In adults with obesity and type 2 diabetes, retatrutide improved blood sugar control and body weight over 80 weeks.
Other reviewed pairs with Retatrutide
Other reviewed pairs with CJC-1295