How do I cycle on and off peptides?
It depends on the peptide class. Growth hormone peptides (CJC-1295, ipamorelin, sermorelin) are often cycled, because continuous use can desensitize the receptors in your pituitary and the peptide may stop working as well over time. Your prescriber can help you decide when a break makes sense. Healing peptides (BPC-157, TB-500) are typically used for a specific injury or healing window rather than run indefinitely. GLP-1s (semaglutide, tirzepatide) are generally not cycled, because they treat a chronic condition and stopping usually leads to weight regain. How long to stay on any peptide, and when to take a break, is a decision for you and your provider.
- GH secretagogues (CJC-1295, ipamorelin, sermorelin): continuous use downregulates GHRH and GHS receptors in the pituitary
- Lee et al. 2018 (Yonsei Medical Journal): six weeks of continuous GHS administration abolished the GH stimulatory effect in rats
- Healing peptides: typically used for a specific injury or healing window rather than continuous use; no established receptor downregulation comparable to GH secretagogues
- GLP-1s: weight regain is expected after stopping (about 65 to 70% within a year)
- Seeds Peptide Protocols Vol. 1 (ISBN 9780578624358) is a clinical reference for cycling considerations
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PRTCL walks beginners through their first peptide with confidence - guided reconstitution, syringe unit math from your own numbers, vial tracking, and answers to questions like this one. Built for first-timers, useful for everyone.
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