Most dosage pages online attach a cycle length to a peptide — four to six weeks for one, eight to twelve for another, often with weeks off in between. The labels and trials behind these compounds tell a different story, and not a single one: some ran for a week, some for a year, two Russian intranasal peptides were given in short courses with a gap, and one US-labelled drug was tested for exactly what happens when the course stops. This page sets each compound's documented duration beside the cycle figure that circulates for it, with the source for each. Every figure is reported from a label, a trial or a dated record of what vendor pages state; none is a suggestion.
How often each compound is given within a course — daily, twice weekly, weekly — is on the dosing frequency page. The single-compound case worked in full, trial by trial, is the tesamorelin cycle page.
Duration on record vs the circulating cycle
| Compound | Longest documented course | Break in the record? | Circulating cycle figure (recorded 2026-09-18) |
|---|---|---|---|
| Tesamorelin | 52 weeks, 2 mg daily (phase 3 extension, PMID 18690162) | No; fat returned after stopping | 5 days on, 2 off, three-month cycles |
| Thymosin alpha-1 | 6 to 12 months, twice weekly (Zadaxin label) | No | — |
| Sermorelin | Up to a year, nightly, in GH-deficient children (Thorner 1996, PMID 8772599) | No | — |
| AOD-9604 | 24 weeks, daily oral tablets (502 adults randomised) | No | 8 to 24 weeks, subcutaneous |
| Selank | 14 days, nasal drops three times a day (Russian label) | Yes: repeat course after 1 to 3 weeks | — |
| Semax | Two 10-day courses (stroke rehabilitation, PMID 29798983) | Yes: 20 days between courses | — |
| Ipamorelin | 7 days, intravenous twice daily after bowel surgery (Beck 2014) | No | 8 to 12 weeks |
| CJC-1295 (DAC) | Two or three weekly or biweekly doses (Teichman 2006, PMID 16352683) | No | — |
| TB-500 | 14 days, intravenous, full-length thymosin beta-4 (Ruff 2010, PMID 20536472) | No | 4 to 6 weeks, then weekly or fortnightly |
| GHK-Cu | 14 days, topical 0.1% gel (NCT07437586, recruiting) | No | 4 to 12 weeks; 5 days on, 2 off |
| BPC-157 | None completed; NCT07803250 plans 90 days, dose unstated | — | 4 to 6 weeks |
| MOTS-c | None in humans; an analogue, CB4211, ran 4 weeks | — | — |
| PT-141 | On demand; label caps 8 doses a month | Frequency cap, not a cycle | — |
A dash means this site's dosage page recorded no circulating cycle figure for that compound, not that none exists. The sources for each row are linked from the compound's own page: tesamorelin, thymosin alpha-1, sermorelin, AOD-9604, Selank, Semax, ipamorelin, CJC-1295, TB-500, GHK-Cu, BPC-157, MOTS-c and PT-141.
Three patterns in the record
Long and continuous. The compounds with real labels and phase 3 programmes were given without breaks for months. Zadaxin's label runs 6 to 12 months; tesamorelin's phase 3 extension ran 52 weeks and kept visceral fat about 18% lower at the end than at baseline; sermorelin's supporting paediatric trial ran nightly for up to a year. None of them pauses for "receptor rest", and the tesamorelin data — a slightly larger effect at 52 weeks than the 15.2% seen at 26 weeks — show no loss of effect over that year.
Short courses with a gap. The only planned breaks are in the Russian intranasal peptides. Selank's label gives a 14-day course and allows a repeat after 1 to 3 weeks; the published Semax stroke-rehabilitation regimen gave two 10-day courses of 6,000 mcg a day with 20 days between them, and a motor-neuron-disease study used two 10-day courses two weeks apart (PMID 18379501). These are the closest the record comes to a "cycle", and they are measured in days, not months.
Brief or none. For the compounds most often sold with a cycle — BPC-157, TB-500, ipamorelin, GHK-Cu — the human record is a week or two, by a different route, or nothing completed. The circulating 4-to-12-week figures are longer than any human exposure documented for them.
When a course ends
Only tesamorelin has a controlled answer to the question a cycle schedule assumes, which is what happens after stopping. In the phase 3 extension, 50 people were switched from tesamorelin to placebo at week 26 without being told; their visceral fat reaccumulated, and the authors concluded that the effects "do not last beyond the duration of treatment" (PMID 18690162). The SMART trial of tesamorelin in older adults re-tested participants after a 10-week washout as a measurement point (PMID 22869065). For every other compound in the table, no study measured the period after a course.
The arithmetic of a cycle
A cycle length turns into an amount of powder. At the circulating figures, four to six weeks of BPC-157 at 250 mcg twice a day is 14 to 21 mg; six weeks of TB-500 at 2.5 mg twice a week is 30 mg; twelve weeks of ipamorelin at 300 mcg a day is 25.2 mg. Each total is the circulating figure multiplied out, not a course. The per-vial arithmetic for any amount is in the reconstitution calculators, and every compound's reported range sits on one table in the peptide dosage chart.
What this page does not do
It does not suggest a cycle length, a break or a course for any compound. It reports how long each label and trial gave each compound, where the record has breaks and where it has none, and what the circulating figures state. Medibact's peptide guide library covers the compounds individually. Decisions about using any of them belong with a clinician.
Sources and dates
Opened 2026-10-20: PubMed abstracts of PMIDs 18690162 (tesamorelin extension, AIDS 2008) and 22869065 (SMART, Arch Neurol 2012); ClinicalTrials.gov v2 API, intervention "tesamorelin". From this site's compound dosage pages, each with its own sources and read dates (2026-09-18 unless noted there): the Zadaxin prescribing information and the Singapore formulary entry; Thorner et al. 1996 (PMID 8772599); the AOD-9604 safety paper; the Russian Selank label (rlsnet.ru); Semax PMIDs 29798983 and 18379501; Beck et al. 2014; Teichman et al. 2006 (PMID 16352683); Ruff et al. 2010 (PMID 20536472); ClinicalTrials.gov records NCT07437586, NCT07803250 and NCT03998514; the Vyleesi label; and the circulating figures from vendor, clinic and forum pages. Totals by this site. Corrections go to the contact page.