Deslorelin

What it is

Deslorelin is a GnRH agonist (LHRH superagonist) that initially stimulates the pituitary-gonadal axis, causing a transient "flare-up" increase in LH, FSH, and sex steroid concentrations. With continued exposure via slow-release implant, it downregulates GnRH receptors on pituitary gonadotrophs, leading to sustained suppression of LH and FSH secretion and consequently reduced gonadal steroid production (testosterone, estradiol, progesterone), interrupting spermatogenesis and ovulation (PMIDs: 55, 44, 52, 13). In prostate cancer research, deslorelin has been conjugated to docetaxel to exploit LHRH receptor targeting on tumor cells, enhancing cytotoxic drug delivery. Deslorelin is also degraded in airway epithelial cells initially at the 3–4 peptide bond by metalloendopeptidase and/or angiotensin-converting enzyme, with degradation faster in the cytosolic than membrane fraction.

Class: Gonadotropin-Releasing Hormone (GnRH) agonist / LHRH superagonist peptide

What it's studied for

• Reversible suppression of fertility / chemical castration in male dogs Mixed
  • Seven male Beagle dogs treated with 4.7 mg deslorelin implant showed testosterone suppression to basal levels from D28, azoospermia from D35–D77, and reduced testicular/prostatic volume; effects were fully reversible after implant removal, though with high individual variation. PMID 36139204 Stempel et al., Animals 2022
  • After implant removal at 5 months, testosterone recovered within 14 days; first sperm-containing ejaculates appeared D49–D70, normospermia achieved D84–D133; normal spermatogenesis confirmed histologically at D149. PMID 36230286 Stempel et al., Animals 2022
  • In 45 male dogs treated with 4.7 mg deslorelin SRI, testosterone and testicular volume were significantly reduced at all monitored time points; after implant removal, recovery was variable with testosterone returning physiologically as early as week 2 in some dogs. PMID 37820614 Vasetska et al., Tierarztliche Praxis 2023
  • Chemical castration with deslorelin implant reduced plasma testosterone and estradiol to levels comparable to surgically castrated dogs; LH and FSH were suppressed below pre-treatment levels; pituitary remained responsive to GnRH at mean 133 days post-implantation. PMID 36165853 Spruijt et al., Reproduction in Domestic Animals 2023
  • Six dogs treated chronically with deslorelin for 2–9 years for various indications; all were in good health during treatment; two developed neoplasias (pituitary carcinoma, bladder carcinoma); chronic treatment regarded as safe. PMID 36670804 Romagnoli et al., Animals 2023
• Reversible suppression of fertility / oestrus control in female dogs (bitches) Mixed
  • Ten bitches administered 4.7 or 9.4 mg deslorelin implant SC; suppression of cyclicity achieved in 6/10 for 1–4 years; no behavioural or local/general side effects observed; bitches implanted in dioestrus showed no heat during treatment. PMID 19754533 Romagnoli et al., Reproduction in Domestic Animals 2009
  • 32 bitches repeatedly treated with 4.7 or 9.4 mg DA for mean 5.3 years; treatment successful (no major side effects) in 26/32 (81%); minor side effects included body weight changes, behavioral changes, induced heat, coat changes, pseudocyesis, transient urinary incontinence. PMID 34339906 Brändli et al., Theriogenology 2021
  • In prepubertal bitches (12–18 weeks old), 4.7 mg deslorelin significantly extended median time to sexual maturity (377 vs. 217 days vs. controls); functional reproductive abilities confirmed after puberty; 3 females expressed induced oestrus. PMID 36552424 Gontier et al., Animals 2022
  • Estrus induction more effective in late anestrus (>160 days after heat cessation); pregnancies noted only in late-anestrus group with implant removed at LH peak (P4 ≥ 3 ng/ml); prolonged implant retention led to hormonal imbalance and no conception. PMID 40015085 Holumbiiovska et al., Theriogenology 2025
• Hair cycle arrest (Alopecia X) in dogs Animal studies only
  • In 20 dogs with hair cycle arrest, 4.7 mg deslorelin implant resulted in hair regrowth in 12/16 intact males (75%) within 3 months; no hair regrowth in neutered females; no adverse effects noted. PMID 25066263 Albanese et al., Veterinary Dermatology 2014
  • Single 4.7 mg deslorelin acetate implant in two intact male Keeshonden with hair cycle arrest resulted in profuse hair regrowth within 3.5 months, enduring at least 14 months; treatment described as safe and affordable. PMID 29757666 Layne & Richmond, JAAHA 2018
  • First reported case of a neutered female Pomeranian with alopecia X successfully treated with 4.7 mg deslorelin acetate implant after failing melatonin; profuse hair regrowth occurred 9 months after first implant. PMID 40271097 Coimbra & Vieira, Brazilian J Vet Medicine 2025
• Fertility control and reproductive suppression in male cats (tomcats) Human RCT
  • See chronic use data above. PMID 36670804 Amaral et al., Animals 2023
  • In a multicenter double-masked RCT of 205 male cats, 4.7 mg deslorelin implant suppressed testosterone ≤0.10 ng/mL in 77.9–84.4% of cats through D279; significantly reduced sexual behaviors, testicular volume, and penile spines; no relevant safety concerns over 372 days. PMID 36766268 Amaral et al., Animals 2023
  • In 14 tomcats treated with 4.7 mg deslorelin and implant removed at 3, 6, or 9 months, AMH concentrations increased significantly during treatment; AMH returned to pre-treatment levels by week 6 post-removal, suggesting restoration of testicular function. PMID 37393746 Ferré-Dolcet et al., Animals 2023
• Reproductive suppression in female cats (queens) — contraception and oestrus control Animal studies only
  • 9.4 mg deslorelin implant in 14 queens provided average 790 ± 155 days (range 525–1140 days) of contraception; treatment fully reversible; no clinically relevant side effects; significant weight gain observed. PMID 39467341 Baldan et al., Theriogenology 2025
  • After surgical removal of 4.7 mg deslorelin implant at 3, 6, or 9 months, resumption of ovarian function took 3–7 weeks; time was longer during decreasing photoperiod. PMID 34610192 Ferré-Dolcet et al., Reproduction in Domestic Animals 2022
• Post-spaying urinary sphincter mechanism incompetence (USMI) in cats Animal studies only
  • Deslorelin acetate implant restored urinary continence approximately 25 days after implantation in a post-spayed queen with USMI; effect maintained for at least 15 months without treatment-related negative effects. PMID 23873046 Pisu & Veronesi, Journal of Feline Medicine and Surgery 2014
• Ovulation induction in mares Animal studies only
  • Deslorelin implants approved for ovulation induction in mares; removal of implant 48 h after administration normalized subsequent interovulatory intervals; without removal, extended interovulatory intervals occurred especially when prostaglandins were also given. PMID 12212887 McCue et al., Theriogenology 2002
  • Deslorelin-induced ovulation in mares was associated with reduced FSH concentrations days 5–14 post-ovulation, smaller follicle diameters during diestrus, and longer interovulatory intervals (25.6 vs. 22.9 days in controls). PMID 11280410 Farquhar et al., JAVMA 2001
• Double ovulation induction in mares for embryo transfer Animal studies only
  • 100 µg controlled-release deslorelin acetate IM every 12h in mares with appropriate follicle sizes resulted in 82% double ovulation rate and embryo recovery of 1.12 per estrous cycle vs. 0.57 in controls. PMID 23182475 Nagao et al., Animal Reproduction Science 2012
• Endometriosis-related pelvic pain (human) Human RCT
  • In a randomized multicenter open-label trial, daily intranasal deslorelin with low-dose estradiol ± testosterone add-back reduced endometriosis symptom/sign scores from baseline average 7.4 to 2.5 at 3 months and 3.4 at 6 months; minimal BMD changes, minimal hot flashes, no endometrial hyperplasia observed. PMID 26881208 Agarwal et al., BioMed Research International 2015
• Central precocious puberty (human) Human RCT
  • In 29 children with central precocious puberty, deslorelin at 4 µg/kg/day SC suppressed gonadotropins; doses of 1, 2, and 4 µg/kg/day produced similar clinical responses; 1 µg/kg/day resulted in less gonadotropin suppression than 4 µg/kg/day on LHRHa stimulation test. PMID 1898743 Pescovitz et al., J Clin Endocrinol Metab 1991
  • In a double-blind RCT, deslorelin at 4 µg/kg/day SC for 4 years in short-statured adolescents with normally timed puberty significantly increased predicted adult height by 7.6 cm compared to baseline and 10.3 cm compared to placebo (p < 0.005). PMID 8077329 Municchi et al., J Clin Endocrinol Metab 1993
• Prostate cancer targeted therapy (preclinical — deslorelin-docetaxel conjugate) In vitro only
  • Deslorelin-docetaxel conjugate showed 15-fold greater antiproliferative potency than docetaxel alone at 72h in LNCaP and PC-3 prostate cancer cell lines, with ~5.5-fold greater tumor growth inhibition in PC-3 xenograft-bearing mice; efficacy was mediated via LHRH receptor. PMID 19509261 Sundaram et al., Mol Cancer Ther 2009
• Reproductive suppression in avian species (pigeons, quail, cockatiels, cranes) Animal studies only
  • 4.7 mg deslorelin implanted intramuscularly significantly reduced LH in female pigeons for at least 84 days and reduced egg production; male LH suppressed at 7, 28, and 56 days; no effect on body weight. PMID 25115038 Cowan et al., J Avian Med Surg 2014
  • 4.7 mg deslorelin implant SC stopped regular egg laying in 78–100% of quail within 5 days; cabergoline alone had no significant influence on egg laying. PMID 35526163 Rückl et al., J Avian Med Surg 2022
  • 4.7 mg deslorelin implant SC significantly reduced plasma triglycerides, total cholesterol, IDL, and HDL at 1 month in female cockatiels; progesterone decreased; effects on lipids persisted up to 2 months for IDL. PMID 41926275 Sosa-Higareda et al., J Avian Med Surg 2026
  • Retrospective study of 67 deslorelin implants in 13 captive cranes of 7 species; varied responses in egg suppression; aggression improved in 2 treated individuals; minimal response for feather destructive behavior. PMID 42405733 Davidson & Boon, J Zoo Wildl Med 2026
• Reproductive suppression in non-human primates Animal studies only
  • Single 4.7 mg deslorelin implant in 6 female rhesus macaques suppressed estradiol and progesterone within 6 days; duration varied: 2 macaques returned to cyclicity by day 96 and 113, while 4 remained suppressed at 6 months. PMID 35512995 Carroll et al., JAALAS 2022
  • Two 4.7 mg deslorelin implants in 4 male rhesus macaques suppressed testosterone in all subjects; onset varied (day 26 to ~2 months); duration varied (70 days to ≥245 days); testicular volume significantly reduced by day 121. PMID 37844997 Tran et al., JAALAS 2023
• Reproductive control in zoo/wildlife mammals (Oryx, olive baboon, grey mouse lemur) Animal studies only
  • Deslorelin implants (14.1 mg and 9.4 mg SC) in male Oryx dammah caused initial fecal androgen increase then progressive decline to basal levels; no births recorded during treatment; contraceptive effect hypothesized up to ~10 months. PMID 32247215 Bonacina et al., Theriogenology 2020
  • 4.7 mg deslorelin implant in one male olive baboon induced transient azoospermia and decreased proxies of aggressiveness and sexual arousal; fertility returned after treatment. PMID 32524631 Martinez et al., J Med Primatol 2020
• Benign prostatic hyperplasia (BPH) in male dogs Animal studies only
  • Deslorelin used chronically for BPH in dogs; all animals in good health during treatment over 2–9 years. PMID 36670804 Romagnoli et al., Animals 2023
  • Deslorelin acetate (Suprelorin) in 15 dogs with BPH led to azoospermia and decreased libido; both deslorelin and osaterone acetate significantly affected canine ejaculate properties. PMID 35739884 Niżański et al., Animals 2022
• Sexual attractiveness reduction in neutered male dogs Human RCT
  • In a double-blind RCT, 4.7 mg deslorelin implant reduced sexual attractiveness to other males in 11/15 treated neutered dogs vs. 5/15 placebo (OR 5.47, p = 0.017); LH suppressed to basal levels; FSH remained elevated in both groups. PMID 42119283 Leber et al., Theriogenology 2026
• Oestrus disruption/suppression in mares Animal studies only
  • 9.4 mg or 28.2 mg (3×) deslorelin sustained-release implants disrupted oestrous cyclicity in 87.5% of treated mares over 12 weeks; 4 of 8 treated mares showed sustained progesterone elevation. PMID 37062896 Joonè & Cavalieri, Australian Vet J 2023
• Reproductive control in reptiles Animal studies only
  • Single or double 4.7 mg deslorelin acetate implants IM in female pond sliders did not successfully inhibit reproduction during the ongoing season; double implant reduced phase II follicles, possibly affecting following-season fertility. PMID 33801422 Bardi et al., Animals 2021
  • Single 4.7 mg deslorelin acetate implant had no significant effect on testosterone concentrations in male Hermann's and Greek tortoises over 5 months. PMID 37173553 Pisu et al., Vet Res Commun 2023
  • GnRH agonist deslorelin implants did not prevent spontaneous reproductive activity in any of 7 female veiled chameleons over 3-year observation. PMID 37982053 Cermakova et al., Veterinarni Medicina 2023
• Reproductive control in fish (freshwater stingrays) Animal studies only
  • Deslorelin acetate implants (4.7 mg and 9.4 mg) in male freshwater stingrays caused plasma testosterone to increase significantly and remain very high for at least 13 months; sperm concentration/motility and testis size unchanged; deslorelin implants considered ineffective and potentially harmful in this species. PMID 36971627 Sailler et al., J Zoo Wildl Med 2023
• Prepubertal female dog reproductive suppression Animal studies only
  • Deslorelin acetate implants in pre-pubertal female dogs suppressed ovarian activity; first implant caused modest estradiol increase and vaginal cornification; juvenile genital tract appearance maintained throughout treatment; genital tract remained juvenile at 18 months. PMID 24467617 Marino et al., Reproduction in Domestic Animals 2014
• Reproductive suppression in guinea pigs Animal studies only
  • 4.7 mg deslorelin implant SC in male guinea pigs did not achieve anticipated decrease in testosterone or cessation of spermatogenesis; deslorelin implant proved ineffective in this species. PMID 32679355 Glocova et al., Theriogenology 2020
• Superovulation/MOET protocols in ewes (pre-treatment) Animal studies only
  • Deslorelin pre-treatment in a MOET protocol for ewes increased follicle synchronization but did not increase corpus luteum number or embryo recovery compared to controls (5.2 ± 0.8 vs. 1.1 ± 0.8 embryos, p < 0.01 favoring control). PMID 39115242 Garcia et al., Reproduction in Domestic Animals 2024
• Reproductive suppression in domestic goats (pharmacokinetics study) Animal studies only
  • 9.4 mg deslorelin SC implant in 3 female goats produced average Cmax of 83 ng/mL, Tmax of 1.3 h, and a plateau phase from 30 to 360 days; fecal estrogen and progestagen reflected anovulatory status in all three goats. PMID 41065688 Rooney et al., J Zoo Wildl Med 2025

Community-reported dosing

Tier key: Research = PMID-cited study · [C] = scraped community source · [S] = model-synthesized from aggregate community reports (softer evidence). How we source.