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approvedHormone Regulation

Histrelin

Also known as: Vantas, Supprelin LA, Histrelin Acetate

Histrelin is a synthetic GnRH agonist delivered as a subcutaneous implant that provides continuous drug release for 12 months, making it the longest-acting GnRH agonist available. FDA-approved as Vantas for palliative treatment of advanced prostate cancer and as Supprelin LA for central precocious puberty, histrelin offers the convenience of once-yearly dosing. The small flexible rod is surgically inserted in the inner upper arm and can be removed if treatment discontinuation is needed — a unique advantage over biodegradable depot formulations. Histrelin achieves reliable testosterone suppression for the full 12-month treatment period in over 95% of patients.

3 cited references·5 researched benefits

Quick Answer

Histrelin (Vantas/Supprelin LA) is a GnRH agonist delivered via a subcutaneous implant in the upper arm that releases drug continuously for 12 months. FDA-approved for advanced prostate cancer and central precocious puberty, it offers the longest dosing interval of any GnRH agonist. The implant can be surgically removed if treatment needs to be discontinued, providing a reversibility advantage over biodegradable depot formulations.

Key Facts

Mechanism
Histrelin is a nonapeptide analog of GnRH containing a D-histidine(benzyl) substitution at position 6, making it approximately 100-200 times more potent than native GnRH. The Vantas and Supprelin LA implants consist of a small hydrogel cylinder (approximately 3 cm long, 3 mm diameter) containing histrelin acetate. The hydrogel matrix provides zero-order drug release over 12 months. Like all GnRH agonists, continuous histrelin exposure initially causes a transient surge of LH, FSH, and sex steroids (the flare effect lasting 1-2 weeks), followed by pituitary GnRH receptor downregulation and profound gonadotropin suppression. Testosterone is reduced to castrate levels within 2-4 weeks and maintained there for the full year.
Research Status
approved
Half-Life
~4 hours (implant provides sustained release over 12 months)
Molecular Formula
C₆₆H₈₆N₁₈O₁₂
Primary Use
Hormone Regulation
Table of Contents

Benefits

  • Once-yearly dosing — the longest interval of any GnRH agonist, eliminating the need for monthly or quarterly clinic visits for injectionsstrong
  • Reliable testosterone suppression — maintains castrate levels for the full 12 months in over 95% of prostate cancer patientsstrong
  • Effective puberty suppression in central precocious puberty — Supprelin LA provides consistent suppression for 12 months with a single implantstrong
  • Removable implant — unlike biodegradable depots, the histrelin implant can be surgically removed if treatment discontinuation is needed, allowing faster hormonal recoverystrong
  • Implant may remain effective beyond 12 months — studies show some implants maintain testosterone suppression for 18-24 months, though annual replacement is standard practicemoderate

Dosage Protocols

RouteDosage RangeFrequencyNotes
Subcutaneous implant (prostate cancer — Vantas)50 mg histrelin acetate implantReplaced every 12 monthsSurgically inserted in the inner aspect of the upper arm under local anesthesia. Old implant removed and new one inserted at the same visit annually. Antiandrogen flare protection recommended at first insertion.
Subcutaneous implant (precocious puberty — Supprelin LA)50 mg histrelin acetate implantReplaced every 12 monthsSame drug and implant as Vantas, marketed separately for pediatric use. Inserted in the inner upper arm. Continued until clinically appropriate age for puberty (typically age 11 for girls, 12 for boys). Annual replacement required.

Medical disclaimer

Dosage information is provided for educational reference only. Always follow your prescriber's instructions and consult a qualified healthcare provider before starting any peptide protocol.

Side Effects

  • Implant site reactions — pain, bruising, soreness, and erythema at the arm insertion site; reported in 5-15% of patientscommon
  • Hot flashes — the most common systemic side effect, affecting 55-65% of prostate cancer patientscommon
  • Testosterone flare — initial 1-2 week hormone surge before suppression; antiandrogen cover recommended for prostate cancer patientsserious
  • Decreased bone mineral density — progressive loss with prolonged androgen deprivation therapyserious
  • Sexual dysfunction — decreased libido and erectile dysfunction due to castrate testosterone levelscommon
  • Implant extrusion or breakage during removal — rare complication where the implant may break into fragments during surgical removal, requiring more extensive retrievalrare
  • Fatigue and mood changes — reported in 10-15% of patients; may include depression and cognitive effectscommon

Frequently Asked Questions

How is the histrelin implant inserted and removed?
The histrelin implant is placed under local anesthesia (lidocaine injection) in the inner aspect of the upper arm through a small incision (approximately 1-2 cm). The implant is a small flexible rod about 3 cm long and 3 mm in diameter. Insertion takes about 15 minutes. For removal, the implant is located by palpation or ultrasound, a small incision is made, and the implant is extracted. A new implant can be inserted through the same incision if treatment continues. The procedure is performed in an outpatient setting.
Does histrelin cause a testosterone flare like Lupron?
Yes. Like all GnRH agonists, histrelin causes an initial testosterone flare during the first 1-2 weeks after implant insertion. In prostate cancer patients, antiandrogen therapy (bicalutamide 50 mg daily) should be started before or at the time of implant insertion and continued for 2-4 weeks to block the effects of the testosterone surge. With subsequent annual implant replacements, the flare is generally less pronounced because the new implant is placed before testosterone has recovered from the previous implant.
What happens if the histrelin implant is not replaced after 12 months?
Some studies have shown that histrelin implants can maintain testosterone suppression beyond the labeled 12 months — some patients remain suppressed for 18-24 months. However, there is significant individual variation, and testosterone escape can occur unpredictably. The FDA-approved labeling recommends annual replacement. If a patient inadvertently goes beyond 12 months, testosterone levels should be checked, and the implant replaced as soon as possible. For precocious puberty, maintaining continuous suppression is essential to prevent breakthrough puberty.
Is Vantas the same as Supprelin LA?
Yes, both contain the identical 50 mg histrelin acetate implant with the same drug release profile. They are marketed under different brand names for different indications: Vantas for advanced prostate cancer in adults, and Supprelin LA for central precocious puberty in children. The FDA mandated separate approvals and labeling for the two patient populations. The implant itself, insertion procedure, and replacement schedule are the same for both products.
How does histrelin compare to monthly Lupron injections for prostate cancer?
Both histrelin (Vantas) and leuprolide (Lupron Depot) are equally effective at achieving and maintaining castrate testosterone levels. The main advantage of histrelin is convenience — one implant per year versus monthly, 3-monthly, or 6-monthly depot injections. The histrelin implant requires a minor surgical procedure for insertion and removal, which some patients find more invasive than an injection. Cost comparison varies by insurance coverage. Some patients prefer the certainty of a fixed implant over remembering appointment schedules for periodic injections.

References

  1. 1
    Histrelin implant in patients with advanced prostate cancer: a 12-month clinical study(2007)PubMed ↗
  2. 2
    Histrelin subcutaneous implant (Supprelin LA) for central precocious puberty: a review(2007)PubMed ↗
  3. 3
    Long-term efficacy and safety of histrelin subcutaneous implant in patients with advanced prostate cancer(2009)PubMed ↗

Latest Research

Last updated: 2026-02-19