Gonadorelin and kisspeptin are compared because both raise LH and, through it, testosterone, and both are sold as research peptides for that reason. They are not alternatives at the same point. Kisspeptin works on the neurons in the hypothalamus that release GnRH; gonadorelin is GnRH, acting directly on the pituitary. That ordering explains most of what the studies found — including why one research group used the two as paired diagnostic tests on the same people. This page reports the doses each record contains, converts them to micrograms, molecules and syringe units, and states what has not been studied (sources re-read 2026-10-12). It reports; it suggests no dose.
Each compound's own record is on gonadorelin dosage and kisspeptin-10 dosage. Kisspeptin's other common comparison, with a melanocortin drug, is on kisspeptin vs PT-141.
Two steps of one chain
| Gonadorelin | Kisspeptin-10 | |
|---|---|---|
| What it is | Synthetic GnRH, 10 residues | C-terminal fragment of kisspeptin (112–121), 10 residues |
| Formula, molecular weight | C55H75N17O13, 1,182.3 | 1,302.4 |
| Acts on | Pituitary GnRH receptor → LH, FSH | KISS1R on GnRH neurons → GnRH → LH, FSH |
| Approved product | Factrel and Lutrepulse (US, both discontinued); veterinary labels current | None |
| Needs working GnRH neurons? | No | Yes |
The last row is the practical difference. In adults with idiopathic hypogonadotropic hypogonadism — whose GnRH neurons do not work — kisspeptin does not raise LH, while GnRH given directly can (Chan 2018 background). That is why the Boston group used kisspeptin as a probe of the hypothalamus and GnRH as a probe of the pituitary.
The study that gave both
In Chan and colleagues' 2018 study, 15 children with delayed or stalled puberty and 5 healthy men each received, on an overnight admission, a single intravenous bolus of kisspeptin and a single intravenous bolus of GnRH. The children then had six days of GnRH pulses under the skin by pump to "prime" the pituitary and were tested again.
| Item | Dose as published | At 70 kg (this site's arithmetic) | nmol/kg |
|---|---|---|---|
| Kisspeptin bolus (IV) | 0.313 mcg/kg | 21.9 mcg | 0.24 |
| GnRH bolus (IV) | 75 ng/kg | 5.3 mcg | 0.063 |
| GnRH priming (SC, every 2 h, 6 days) | 25 ng/kg | 1.75 mcg per pulse; 21 mcg a day | 0.021 |
Results, as the paper reports them: in the healthy men the kisspeptin-induced LH pulse averaged 4.9 ± 2.0 mIU/mL and the LH rise after GnRH 11.4 ± 6.2. Of the children, six with spontaneous overnight LH pulses all responded to kisspeptin, as did one more; seven did not respond and one was intermediate. By molecules, the kisspeptin test dose was about 3.8 times the GnRH dose — yet GnRH gave the larger LH rise in the men. The doses were set to answer diagnostic questions, not to match the two compounds, so this is a description of two tests and not a potency ranking.
Kisspeptin also varies with the menstrual cycle. In 31 women given 0.24 or 0.72 nmol/kg intravenously, LH pulses followed in every luteal and preovulatory woman but in only half of those in the early follicular phase, and tripling the dose did not help (Chan 2012).
The approved and labelled gonadorelin doses
| Use | Dose | Source |
|---|---|---|
| Hypothalamic amenorrhoea (Lutrepulse) | 5 mcg IV every 90 min by pump, up to 20 mcg | Label as quoted in NCT01976728 protocol |
| Stimulation test (Factrel) | 100 mcg IV once | Presse Med 1988 |
| Cattle (Factrel and others) | 100–200 mcg IM | Current DailyMed veterinary labels |
At the Lutrepulse starting rate, 16 pulses a day is 80 mcg a day; the 2018 priming schedule at 70 kg was 21 mcg a day. Kisspeptin has no labelled dose of any kind. A dosage page reviewed 21 May 2026 states 50–250 mcg of gonadorelin under the skin two to three times a week alongside testosterone, calling that use off-label; vendor and forum figures for kisspeptin-10 are 50 to 200 mcg once or twice a day. Neither set comes from a trial.
Regulator and sport status
| Gonadorelin | Kisspeptin-10 | |
|---|---|---|
| FDA safety-risk list (content current 2026-04-22) | Not listed | Listed (503A, 2023-09-29): immunogenicity risk; "no, or only limited, safety-related information" |
| US human product | Discontinued | Never approved |
| WADA 2026 | S2.2.1, "GnRH, gonadorelin" | S2.2.1, "kisspeptin and its agonist analogues" |
Both are prohibited in sport in the same clause — testosterone-stimulating peptides in males — which places them on the same footing in an athlete's case whatever their mechanism.
The amounts in syringe units
Gonadorelin is sold in 2, 5 and 10 mg vials and kisspeptin-10 in 5 and 10 mg. The study and label doses are tiny next to those vials:
| Amount | 1,000 mcg/mL (2 mg in 2 mL) | 2,500 mcg/mL (5 mg in 2 mL) | 5,000 mcg/mL (10 mg in 2 mL) |
|---|---|---|---|
| 5 mcg (Lutrepulse pulse) | 0.5 units | 0.2 units | 0.1 units |
| 21.9 mcg (kisspeptin test, 70 kg) | 2.2 units | 0.9 units | 0.4 units |
| 100 mcg | 10 units | 4 units | 2 units |
| 250 mcg | 25 units | 10 units | 5 units |
Below about one unit a U-100 syringe cannot show the amount at all, which is why the studies used pumps and intravenous lines rather than insulin syringes. The arithmetic for other combinations is on the gonadorelin calculator and the kisspeptin-10 concentration and units tool; how the smallest marks read is on insulin syringe units.
What is not established
No human study has used gonadorelin and kisspeptin together as a regimen; the four PubMed records naming both describe heifers, rabbits and sows. No trial compares repeated subcutaneous use of either to maintain testosterone, and the 2018 comparison was a pair of diagnostic tests in 20 people. Kisspeptin's response depends on cycle phase and on working GnRH neurons, so a figure from one group does not transfer to another. Product and dose decisions belong with a clinician. Medibact's gonadorelin guide and kisspeptin-10 guide cover each compound.
Sources and dates
Opened 2026-10-12: Chan et al., JCI Insight 2018 (PMID 29669934, full text); Chan et al., J Clin Endocrinol Metab 2012 (PMID 22577171, abstract); PubChem CIDs 638793 and 25240297; PubMed search for gonadorelin and kisspeptin together (4 records); FDA, "Certain bulk drug substances for use in compounding that may present significant safety risks" (content current as of 2026-04-22); the 2026 WADA Prohibited List as published in Tractatenblad 2026 no. 25, section S2.2.1. From this site's compound pages (opened 2026-09-18 and 2026-09-28): Drugs@FDA for NDAs 018123 and 019687, the NCT01976728 protocol, PMID 2964021, the DailyMed veterinary labels and the circulating figures. Per-kilogram, molar and unit arithmetic by this site. Corrections go to the contact page.