Cycle length is where most amateur peptide protocols fall apart. Either someone starts a compound and quits at week 2 because they didn't feel anything (too soon), or they run the same dose for 6 months and wonder why the effect flattened (too long). Both errors come from the same root cause: nobody picked a length on purpose.
This piece is a compound-by-compound reference. The standard windows, why they're the standard, three stack templates that work, and the 4 mistakes that quietly burn a cycle. The goal is a defensible plan you can run for 12 to 16 weeks without guessing.
Why cycle at all
Most peptides bind a specific receptor on the cell surface. Hit the same receptor non-stop and the body responds in two ways. It reduces the number of receptors on the cell (downregulation). It also reduces how sensitive each one is to the signal (desensitization). The practical result: same dose, less effect over time.
This is well-documented in growth hormone secretagogues, in weight peptides (to a lesser degree), and in opioid receptor pharmacology more broadly. A planned off-period lets the receptors reset, so the next cycle starts from baseline instead of from a numbed-down state.
Repair peptides like BPC-157 are slightly different. The cycle limit there isn't about receptors. It's about matching the timeline of the actual healing process. A tendon takes 4 to 8 weeks to remodel. Running BPC-157 for 16 weeks straight doesn't give you twice the healing on a finite injury.
Cycle reference by category
Repair and recovery
| Compound | Typical cycle | Frequency | Off-period |
|---|---|---|---|
| BPC-157 | 4 to 6 weeks | Daily, often split AM/PM | 2 to 4 weeks |
| TB-500 | 4 to 6 weeks | Twice weekly loading, then weekly | 4 to 6 weeks |
| GHK-Cu (systemic) | 6 to 12 weeks | Daily or 5x weekly | 2 to 4 weeks |
BPC-157 protocols often run "to injury resolution plus 1 week" instead of a fixed calendar. If a tendon issue clears at week 3, finishing through week 4 is the common pattern. TB-500 has a longer half-life and is dosed less often.
Growth hormone axis
| Compound | Typical cycle | Frequency | Off-period |
|---|---|---|---|
| CJC-1295 (DAC) | 12 weeks | Once weekly | 4 weeks |
| CJC-1295 (no DAC) + Ipamorelin | 8 to 12 weeks | Nightly (5/2 or 6/1 schedule) | 4 weeks |
| Tesamorelin | 12 to 26 weeks | Nightly | 4 to 8 weeks |
| Sermorelin | 12 weeks | Nightly | 4 weeks |
The "5 on, 2 off" weekly pattern (Monday to Friday with weekends off) is a research convention that gives the pituitary regular short breaks even inside an active cycle. It isn't universal, but it's the most common cadence in published GH-axis protocols.
Weight peptides (GLP-1 class)
| Compound | Trial cycle | Frequency | Off / taper |
|---|---|---|---|
| Semaglutide | 24 to 68 weeks | Weekly, titrated | Gradual taper |
| Tirzepatide | 40 to 72 weeks | Weekly, titrated | Gradual taper |
| Retatrutide | 48 to 60 weeks (Phase 2) | Weekly, titrated | Gradual taper |
Weight peptides break the "cycle short" rule because their pharmacology is different. Receptor downregulation does happen, but the practical effect at trial doses is small enough that long, continuous dosing produced most of the weight signal in published Phase 2 and 3 research. For these, the cycle question is really a titration question (a slow ramp from 2.5 mg to 5, 7.5, 10, 15 mg weekly) more than an on/off question.
Longevity
| Compound | Cycle pattern | Frequency |
|---|---|---|
| Epitalon | 10 to 20 day loading, 1 to 2x per year | Daily during load |
| NAD+ | 10 to 30 day loading, 1 to 4x per year | Daily during load |
| GHK-Cu (longevity dosing) | 12 weeks on, 4 weeks off | Daily |
Longevity protocols are pulse-loaded rather than continuously dosed, mirroring the research framework used by groups like the Khavinson group in Russia for Epitalon. The twice-yearly load is a common simplification.
Stacking: when on-cycles overlap
A well-built stack pairs compounds with different mechanisms but compatible cycle lengths. Three workable templates:
Repair + GH axis (16-week protocol)
- Weeks 1 to 6: BPC-157 daily (repair phase)
- Weeks 1 to 12: CJC-1295 + Ipamorelin nightly, 5 on / 2 off (GH axis)
- Weeks 13 to 16: full wash-out
Recomp protocol (12 weeks)
- Weeks 1 to 12: Tesamorelin nightly
- Weeks 1 to 8: GHK-Cu daily (skin and recovery support)
- Weeks 1 to 4: BPC-157 daily (any pre-existing tendon issue)
Longevity pulse (1 month)
- Days 1 to 14: Epitalon daily
- Days 15 to 30: NAD+ daily loading
- Then off for 6 months before the next pulse
Tracking the cycle: the 4 numbers that matter
Without a log, you can't tell whether a cycle is working. The four numbers to capture every 2 weeks:
- Subjective sleep score (1 to 10). GH axis compounds usually improve slow-wave sleep first. This is the earliest signal.
- Bodyweight (morning, after bathroom). Weekly average, not daily readings. Weight peptides show a clean weekly drop curve.
- Recovery score from any wearable. WHOOP, Garmin, Oura. Most are internally consistent enough to track week-over-week trend.
- One injury or pain target. If you're running BPC-157 for a tendon, rate the symptom 1 to 10 every Sunday.
The 4 mistakes that burn a cycle
- Skipping the loading phase. TB-500 and NAD+ both have research-backed loading phases. Skipping straight to maintenance dosing delays the effect.
- Quitting too soon. Pulling the plug at week 3 of a 12-week GH-axis cycle throws out the slow-build effects.
- Running too long. Same dose for 6 months on CJC + Ipa burns the receptor sensitivity you started with.
- No off-period. Off-cycles are when the body resets. They aren't a break for the user. They're part of the protocol.
The one number to remember
If you only keep one heuristic from this piece: on-time + off-time = your full cycle. The off-time is not optional. A 12-week-on / 4-week-off cycle is a 16-week commitment, not a 12-week one. Plan accordingly.