On/off windows: peptide cycle design basics
Most peptide routines are cyclical: weeks on, weeks off. The reasons are partly pharmacological and partly practical, and the decision of how long each window lasts is where a lot of otherwise-good protocols quietly fail.
Why cycle at all
Growth-hormone-axis peptides like CJC-1295, Ipamorelin, and Sermorelin act through the pituitary. Continuous stimulation of pituitary receptors leads, predictably, to receptor downregulation: the signal weakens even at the same dose. An off window gives receptors time to recover. The evidence is strongest for GHRP-class peptides and less clear for BPC-157, where continuous use during an active injury has been the protocol of choice in the community literature.
Metabolic peptides like Semaglutide and Tirzepatide are typically dosed continuously during weight management, with titration and maintenance phases rather than hard off windows. The principle differs because these are GLP-1 agonists with long half-lives where the goal is steady state. When the prescribing frame is "keep serum levels constant," cycling off is not the tool.
The 28/56 default
A common baseline for growth-axis and healing peptides is 28 days on, 56 days off. That reflects two observations. First, meaningful tissue response takes weeks, not days, so shorter on-windows rarely produce the reported effect. Second, doubling the off window biases the cycle toward recovery, which tends to produce steadier long-term outcomes than aggressive on-windows with short recovery.
This is a default, not a prescription. Some protocols run 56 on and 56 off, others run 14 on and 28 off, and the right answer depends on the peptide, the goal, and what your clinician and your labs are telling you.
Taper or hard stop
For peptides with strong acute effects, tapering the last week of an on-window is gentler than a hard stop. The taper prevents the rebound effect that some users describe after sudden cessation of GHRP-class peptides, including poor sleep and an appetite shift. For healing peptides like BPC-157 or TB-500, hard stops are acceptable and common. For any peptide used at clinically active doses, including GLP-1 class, hCG, and Gonadorelin, dose changes should be negotiated with a clinician rather than planned unilaterally.
Planning vs surviving
Most protocols start clean and drift. A cycle written on paper survives about two weeks before travel, illness, or a missed vial breaks the pattern. Two principles keep a cycle alive: log every dose as it happens, and resist the urge to compensate for missed doses by doubling the next one.
Doubling is the failure mode that looks like discipline. It is not. Every peptide has a concentration-response curve, and driving the concentration above the shoulder of the curve produces side effects out of proportion to benefit. If you miss a dose, skip it, note the gap, and continue on the normal schedule.
Stacking rules of thumb
Stacks combine peptides that hit different pathways. A common healing stack pairs BPC-157 with TB-500; a common growth stack pairs CJC-1295 with Ipamorelin. The reason stacks work is pathway separation. The reason stacks fail is dose math: two peptides at half their individual dose are not half as strong at each axis, and running both at a full individual dose is usually more than the sum of the parts in side effects.
Simple rule: introduce one peptide at a time. Run the single-peptide cycle, note the response, then add the second on the next cycle. If you cannot tell which peptide is producing which effect, the stack is not teaching you anything.
How Pepture helps
Pepture's cycle planner tracks on/off windows, missed doses, and the cumulative dose per cycle so the plan and the reality stay in sync. You can load a stack template from the routines library, or build your own. The app flags when a cycle window closes so you do not drift past it by a week without noticing, which is the most common way protocols stop working without you knowing why.