Goserelin (Zoladex)_Dosage, benefits & legal status
Also known as Zoladex
A GnRH agonist given as an implant under the skin rather than an injection.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is Goserelin (Zoladex)?
Plain language first. The technical label stays, but it never stands alone.Overview
The same hormone shutdown as leuprolide, given as a small pellet under the skin of the belly that dissolves over one or three months.
Goserelin acetate, a synthetic GnRH agonist supplied as a biodegradable subcutaneous implant in 1-month and 3-month formulations. FDA-approved 1989. Indications include advanced prostate cancer, breast cancer in premenopausal women, and endometriosis, with additional clinical use for ovarian protection during chemotherapy.
What it's used for
A prescription drug for prostate cancer, breast cancer and endometriosis.
How does Goserelin (Zoladex) work?
What it does in the body, and where.Goserelin differs from leuprolide mainly in how it is delivered, which is not a trivial difference.
- 01Same desensitisation mechanismContinuous GnRH receptor stimulation leads to pituitary downregulation and suppressed sex hormone production, after an initial flare.
- 02Delivered as a biodegradable implantA small cylinder is placed under the skin of the abdomen with a wide-bore needle and releases drug over one or three months. There is nothing to inject daily and nothing to remove.
- 03It carries a breast cancer indication that leuprolide does not lead withGoserelin is used in premenopausal breast cancer to suppress ovarian estrogen production, which is a distinct clinical role within the same drug class.
What else is it used for?
Each use below carries its own evidence level. Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
- Advanced prostate cancerFDA-approved
- Breast cancer in premenopausal womenFDA-approved
- Endometriosis and endometrial thinning before surgeryFDA-approved
- Protecting ovarian function during chemotherapyClinical use
The published record
Papers and trials about Goserelin (Zoladex)
445 papers tagged human · 301 not reviews or lab · 155 clinical trial publications
416 registered trials · 33 with posted results
Furthest stage reached: Approved in the US
Counted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count. 486 papers and 100 trials indexed in detail.
At a glance
Four things to know about Goserelin (Zoladex)
Evidence
FDA-approved
Category
Sexual and hormonal
Common vial
Varies
Half-life
About 4 hours in men, about 2 in women
How much, and do you cycle it?
The range, and whether you take breaks.Set by the label, monthly or 3-monthly implant. Set by the prescription FDA label
This is a prescription drug. Duration and schedule are set by the label and the prescriber, not by a cycling convention.
About 4 hours in men, about 2 in womenFDA label
One of the few compounds in the library with a different figure by sex. The label gives about 4.2 hours in men and about 2.3 in women. In patients with impaired kidney function it rises to about 12.1 hours. These figures are for goserelin itself, not for how long the implant keeps releasing it, which runs 28 days.
Source: Zoladex label sections 8.6 and 12.3
You can compare this against the whole library to see where it sits.
How do I dose and price it?
Enter your vial and your dose. Pick a mix. We show the draw and the cost.The vial holds a fixed amount of drug. Adding more water does not make more drug, it just spreads it thinner, so you draw a bigger number on the syringe for the same dose.
Choose your mix
Measuring the water1 mL = one full 100-unit syringe.
How do you store it?
Before mixing, and after.Dry powder in the freezer or fridge. Once mixed, fridge, and use within about a month.
Unmixed lyophilized Goserelin (Zoladex) keeps for a long time cold. Once you add water the clock starts: most reconstituted vials hold up for roughly 28 to 30 days at fridge temperature. Keep it out of light, and do not freeze it after mixing.
What are the side effects and cautions?
Known cautions and warnings for this compound.Solubility, computed: 30% charged residues, 30% hydrophobic. Water usually sufficient.
A first-pass rule from peptide manufacturers' guidance. It does not account for disulfide bridges, salt form or how the powder was dried, and it predicts what should be easy rather than what will happen in your vial.
Who should avoid it
- Pregnancy, where it can cause harm to a developing baby
- Undiagnosed abnormal vaginal bleeding
- Known hypersensitivity to GnRH analogs
- Use outside a prescription, where no label governs the dose
Stop and get help
- Worsening bone pain or urinary difficulty in the first weeks, which can reflect the initial flare
- Signs of an allergic reaction, including facial or throat swelling or trouble breathing
- Severe pain, swelling or bleeding at the implant site
Common effects
- Hot flushes
- Reduced libido and sexual function
- Mood changes
- Bone density loss with long term use
- Bruising or pain where the implant is placed
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is Goserelin (Zoladex) approved?
And where the numbers on this page come from.Yes. Goserelin (Zoladex) is FDA approved and available on prescription in the United States.
- Approval statusFDA-approved
- RouteAs an implant under the skin
- Checked24 August 2026
- DoseFrom the drug label. The manufacturer tested this range and a regulator reviewed it.
- Vial sizeFrom what vendors typically list; not a recommendation.
- SourcesNone traced yet.
What has happened recently
FDA-approved 1989 as a subcutaneous implant for prostate cancer, breast cancer and endometriosis. Prescription only.
You can compare this against the whole library, or read how to check a seller.
What else is like Goserelin (Zoladex)?
Others in Sexual and hormonal, side by side.If you're weighing Goserelin (Zoladex), it's worth reading Lanreotide (Somatuline Depot), Leuprolide (Lupron), and Lutetium-177 dotatate (Lutathera) in the same class.
A GnRH agonist given as an implant under the skin rather than an injection.
- Dose
- Set by the label
- How often
- Monthly or 3-monthly implant
An approved monthly somatostatin shot that lowers growth hormone and slows some gut and pancreatic tumors.
- Dose
- 60 to 120 mg every 4 weeks (label)
- How often
- Every 4 weeks (6 to 8 weeks for some acromegaly patients)
The GnRH agonist that shuts hormones down by overstimulating them first.
- Dose
- Set by the label and the depot formulation
- How often
- Monthly to six-monthly depot
A peptide used as a delivery van: it finds tumour cells with somatostatin receptors and irradiates them from the inside.
- Dose
- 7.4 GBq every 8 weeks, 4 doses (label)
- How often
- Every 8 weeks, for 4 doses
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
Sources
No primary source has been traced for this compound yet. Treat everything on this page as unverified until one is. How we grade evidence
Beyond these, 586 records are indexed. Browse the records