Cycle length by peptide class
How long peptide cycles should run by class — recovery, GH secretagogues, IGF-1 LR3, MOTS-c, GHK-Cu — with reasoning for each cycle length and off period.
Updated May 7, 2026 · 5 min read
Cycle length isn't arbitrary. Each peptide class has a cycle length that's tied to how long its effects take to express, how the receptors involved respond to chronic stimulation, and what theoretical safety concerns get more weight at month 4 than at month 1. Running cycles too short means quitting before the protocol earns out. Running them too long compounds desensitization and side-effect drift.
This is the reference table for typical cycle lengths and off periods, with the reasoning for each.
The full reference table
| Peptide class | Typical cycle | Off period | Reasoning |
|---|---|---|---|
| BPC-157, TB-500 (recovery) | 4-8 weeks | 4-8 weeks | Match recovery goal; avoid chronic angiogenic signaling |
| Short-acting GH secretagogues (Ipa, CJC no-DAC, Sermorelin) | 12-16 weeks | 4-8 weeks | GH-axis effects need 8+ weeks to express |
| Long-acting GH secretagogues (CJC DAC) | 12 weeks | 8+ weeks | Higher receptor desensitization concern |
| MK-677 | 8-12 weeks | 4-8 weeks | Insulin-sensitivity drift on long runs |
| IGF-1 LR3 | 4-6 weeks | 4-8 weeks | Receptor desensitization plus cancer-axis caveats |
| MOTS-c | 8-12 weeks | 4-8 weeks | Match metabolic adaptation timeline |
| GHK-Cu (topical) | Continuous OK | — | Cosmetic-grade, decades of safety |
| GHK-Cu (injection) | 6-12 weeks | 4 weeks | Less data on chronic injectable use |
| Tesamorelin | Per indication | Per indication | FDA-approved for HIV-LD; cycle off-label |
Each row deserves a closer look.
Recovery peptides: 4-8 weeks
BPC-157 and TB-500 are tools for specific repair goals. Once the goal is met (the tendon healed, the gut is calmer, the training block ended without injury), the rationale for continuing is thin.
| Sub-pattern | When it fits |
|---|---|
| 4-6 weeks | Acute, well-localized injury |
| 6-8 weeks | Chronic tendinopathy or stacked BPC + TB-500 |
| Continuous low-dose oral BPC-157 | Some users for chronic GI conditions — limited evidence |
The pre-clinical record is mostly on healing models, not chronic preventive use. Continuous angiogenic signaling has theoretical (not demonstrated) cancer concerns that are reason enough to default to cycling.
For protocol detail, see BPC-157 dosing protocols and TB-500 dosing protocols.
Short-acting GH secretagogues: 12-16 weeks
This is the cycle length that confuses first-time users most. GH-axis effects (body composition, sleep quality consolidation, IGF-1 elevation, recovery improvement) take time to express. Quitting at week 4 because nothing dramatic happened is the most common mistake.
The 12-16 week window is what the strength community has converged on as the minimum to evaluate effect, with 4-8 weeks off afterward. Short-acting secretagogues preserve the natural pulsatile pattern, so receptor desensitization is less of a concern than with long-acting forms — cycling here is more about giving the GH axis a normal-physiology window than about avoiding tachyphylaxis.
For more, see GH stack: Ipa + CJC and cycling vs continuous use.
Long-acting GH secretagogues: 12 weeks max
CJC-1295 with DAC produces sustained GHRH elevation rather than discrete pulses. MK-677 produces sustained ghrelin-receptor activation. Both are more prone to:
- Receptor downregulation over time
- Side-effect drift (water retention, fasting glucose elevation, carpal-tunnel symptoms)
- Cumulative metabolic shifts that take longer to reverse
The 12-week ceiling and 8+ week off period reflect those concerns. Continuous use is not recommended for either.
IGF-1 LR3: 4-6 weeks
The shortest standard cycle in the category, for two reasons:
- Receptor desensitization — IGF-1 receptors downregulate with sustained ligand exposure. Beyond 4-6 weeks, the same dose produces less effect.
- Cancer-axis caveats — chronic supraphysiological IGF-1 elevation is the relevant theoretical concern. Cycling reduces total exposure.
A 4-6 week IGF-1 LR3 cycle followed by a 4-8 week off period is the typical framework. Stacking with synthetic HGH is not a protocol this site covers — that combination compounds the same pathway risks. See IGF-1 LR3 protocol for dosing detail.
MOTS-c: 8-12 weeks
MOTS-c works through metabolic adaptation (AMPK activation, mitochondrial efficiency). The cycle length matches how long that adaptation takes to express. Long enough to see effect, short enough to give the system a normal-physiology window before reassessing.
GHK-Cu: depends on route
| Route | Pattern |
|---|---|
| Topical | Continuous OK — cosmetic-grade products have decades of safety data |
| Injection | 6-12 weeks on, 4 weeks off — much less data on chronic injectable use |
This is one of the few peptides where route matters dramatically for cycling decisions. See GHK-Cu pillar for more.
What "off" means
A few clarifications about the off-period column:
- Off means zero, not lower. Substituting another peptide just to "stay on something" is continuous use with extra steps.
- Off period should be at least 5 half-lives of the peptide before counting the recovery window
- Long-acting peptides extend the off period. CJC-1295 DAC's ~7-day half-life means the first 4-5 weeks of "off" are the peptide clearing
- Stacked peptides with different schedules complicate this — the cycle "ends" when both have been zero for the off-period
For more on what to do during off-cycles, see off-cycle strategies.
Choosing within the range
Most ranges in the table have a low end and a high end. How to pick:
| Choose the low end when | Choose the high end when |
|---|---|
| First cycle of this peptide | Established response and tolerance |
| Established side-effect concerns | Goal hasn't fully expressed at the low-end mark |
| Conservative practitioner approach | Specific training or recovery target |
Going beyond the high end of the range is the bigger mistake than running short. Side-effect drift and receptor desensitization compound; a 20-week run of a 12-week peptide isn't 1.5x as effective.
Common cycle-length mistakes
- Quitting GH secretagogues at week 4 (too early to evaluate)
- Running IGF-1 LR3 longer than 6 weeks (desensitization plus risk profile)
- Taking 1-2 week "mini-breaks" instead of full off periods (doesn't restore baseline)
- Stacking peptides with mismatched cycle lengths and ending one mid-cycle of the other (hard to attribute effects)
For the broader list, see stacking and cycling mistakes.