Scientific context only. Not medical advice, not a recommendation to use.
At a glance
Goserelin is a synthetic decapeptide and an agonist of gonadotropin-releasing hormone (GnRH). The medical literature describes it as a hormonal agent that suppresses the release of sex hormones through sustained receptor stimulation. Regulatory-approved indications include prostate cancer, advanced breast cancer, endometriosis, and endometrial thinning, among others.
Researched for
Prostate cancerAdvanced breast cancer in pre-/perimenopausal womenEndometriosisEndometrial thinning prior to gynecological proceduresOvarian function suppression during chemotherapy
Official status
US: Prescription
In the United States, goserelin (brand name Zoladex) is FDA-approved as a prescription drug, including for prostate cancer, advanced breast cancer, endometriosis, and endometrial thinning.
As a GnRH agonist, goserelin binds to the GnRH receptors of the pituitary gland. Initial stimulation transiently raises luteinizing hormone (LH) and follicle-stimulating hormone (FSH). With continuous receptor occupancy, however, the receptors become desensitized and down-regulated, which reduces LH and FSH secretion and consequently the production of testosterone or estrogen. This mechanistic relationship is documented in the pharmacological literature.
02
Evidence at a glance
Reading note. The distribution shows on which evidence tier each observation sits. Strong colours mark stronger evidence — weaker tiers are deliberately visible, not hidden.
3 observations · 2 tiers
Human RCT
2
Human trial
1
03
What the studies show
Human trial
Mensch
Bajetta E et al. 1994
Human studies observed suppression of circulating sex hormones down to castration levels.
What does NOT follow: Observation from a clinical study in a defined patient group; not generalizable to other contexts. Not a usage recommendation.
Human RCT
Mensch
Moore HCF et al. 2015
In a randomized trial, premenopausal patients receiving concurrent chemotherapy showed a lower rate of ovarian failure when goserelin was added.
What does NOT follow: Result of a single randomized trial with a limited number of participants in a specific oncological setting; not generalizable. Not a usage recommendation.
Human RCT
Mensch
Kaufmann M et al. 2007
In an adjuvant randomized trial, no significant benefit of goserelin on disease course was detected after risk-adapted chemotherapy.
What does NOT follow: A non-significant result from a single trial does not prove absence of effect across all subgroups; consider study context. Not a usage recommendation.
04
Where studies disagree
Open question
Does goserelin provide a benefit in the adjuvant breast cancer setting?
POSITION A
The POEMS trial observed protection of ovarian function during concurrent chemotherapy.
POSITION B
The GABG-IV B-93 trial found no significant benefit on disease course.
CURRENT STATE · Different endpoints, populations and study designs explain the differing results; the benefit is endpoint- and context-dependent.
05
Pharmacokinetics
Theoretical concentration curve at a half-life of 4.2 h. Pure pharmacokinetic model — not a dosing recommendation.
Which routes of administration the available studies describe — neutral reporting, not a usage guide.
Subcutaneous
The scientific and regulatory literature describes goserelin as a subcutaneous depot implant. This is a purely factual description of the route of administration documented in studies and not instructions for use.
06d
Safer use & risks
Risk notes for harm reduction — descriptive, not a usage or dosing guide.
⚠ Important — please read
This platform does NOT provide usage or dosing instructions. The points below describe risks and are meant to help avoid harm — they do not replace medical advice. Anyone who uses a substance should discuss it with a doctor.
This substance is approved (in at least one country) — use belongs in medical hands, within the approved indication and a physician-set dose.
Online numbers are not a benchmark
Amounts from TikTok, YouTube and forums are mostly imitation rather than data — and are often wrongly derived from animal studies (µg/kg). Not a reliable benchmark for humans.
Sterility & infection risk
Injection solutions prepared or stored non-sterile carry an infection and abscess risk. Contamination is common with grey-market product.
Unknown product quality
Research-/grey-market product is not quality-tested: identity, purity and actual content are often unknown, and counterfeits occur.
Mind interactions
Combinations with medications or pre-existing conditions can carry risks (see the Interactions section). Clarify with a doctor beforehand.
Warning signs — seek medical help
With persistent pain, redness/swelling at the injection site, fever, shortness of breath, racing heart, chest pain or allergic reactions, seek medical help immediately.
A doctor, not a forum
Concrete questions about use and amount belong in a conversation with a doctor — not in a comment thread.
07
Known adverse events from studies
Factual reporting of what studies observed. Not a safety statement for individual use.
Human trial
Clinical studies and official prescribing information describe symptoms of hormone withdrawal, including hot flashes and changes in bone density with prolonged use.
Frequency and severity vary by population and duration of use; complete information only in official prescribing documents. Not a usage recommendation.
Human trial
At the start of use, the initial receptor stimulation can cause a transient rise in sex hormones (so-called flare effect), which is documented in the literature.
Mechanistically grounded effect described in the literature; clinical relevance is context-dependent. Not a usage recommendation.
07b
Interactions & combinations
Documented interactions and contraindications from studies, prescribing information and guidelines. Where no data exists, this is stated.
Reporting of risks, NOT a combination guide. The absence of an entry does not mean „safe to combine“ but „not sufficiently studied“.
No documented interactions recorded
We have not yet found robustly documented interactions for this peptide. This does NOT mean none exist — the data is limited.
10
Anecdotal observations
Weakest evidence tier — not supported by studies
Reading note. This section gathers popular claims from communities and forums. They are explicitly marked as weakest-tier evidence. Unblinded self-reports are particularly prone to placebo, recall and confirmation biases.
Why no amounts or protocols are listed here. We deliberately show only WHAT communities report — not in what amount or how it is used. Anecdotal "doses" or "biohacker protocols" are neither verified nor standardised nor safe; publishing them would be a usage guide, which we do not provide on principle. Specific amounts belong in a conversation with a doctor, not in a forum.
The initial flare effect (a brief rise in hormones and symptoms at the start of therapy) is frequently described.
recurring topic in endometriosis communities
Not supported by studies: The flare is a pharmacologically expected, documented phenomenon of GnRH agonists — a report, not a usage instruction.
10b
What online communities discuss
Recurring themes from Reddit, Quora and patient forums — synthetically summarised, sources linked. Not scientific evidence, but a signal of what users report. Deliberately separated from the study base.
Non-scientific sources. What users report in forums — synthetically summarised, paraphrased, with link to source. Not validated by studies.
Sorted by discussion frequency · 1 Thema
Discussion frequency: ~103 aggregated reviews
On drugs.com, goserelin (Zoladex) scores 6.6 out of 10 across roughly 103 reviews (52% positive, 21% negative). In endometriosis, menopause-like effects dominate (hot flashes, mood swings); at the start of therapy the so-called flare (a brief worsening of symptoms) is frequently discussed.
What this does NOT mean:Review platforms are self-selected, unblinded and not representative; the figures are a snapshot (as of June 2026). They do not replace controlled data — see the studies section. Indications range from endometriosis to prostate cancer; reports are correspondingly heterogeneous.
In the United States, goserelin (brand name Zoladex) is FDA-approved as a prescription drug, including for prostate cancer, advanced breast cancer, endometriosis, and endometrial thinning.
2026-06-07
Germany
Prescription
In Germany, goserelin is available as a prescription drug (brand name Zoladex) and is subject to medicines regulation. Use occurs exclusively under medical prescription.
2026-06-07
12
Reconstitution calculator
Pure mg/mL maths — works like a calculator. Not a usage recommendation.
Peptides ship as a dry powder. Once dissolved in a liquid (reconstitution), this calculator answers a single question: how much substance is in one millilitre of solution afterwards?
1Enter the vial's substance amount (printed on the label).
2Enter how much solvent you add.
3Result = concentration in mg per mL.
Printed on the label
/
Liquid you add
=
2.50
mg / mL
5 mg in 2 mL gives 2.50 mg/mL — each millilitre contains 2.50 mg of substance.
A randomised trial of goserelin versus control after adjuvant, risk-adapted chemotherapy in premenopausal patients with primary breast cancer - GABG-IV B-93