Sounds like 'go-ser-el-in'

Key points about goserelin

  • Goserelin is used for many conditions such as endometriosis, uterine fibroids, breast cancer and prostate cancer. It's also used in fertility and transgender treatment.
  • It's given as an injection under your skin on your stomach (abdomen).
  • Goserelin is also called Zoladex.
  • Find out more about goserelin including possible side effects.
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Goserelin belongs to a group of medicines called antihormonal medicines. This means that it affects the levels of various hormones including testosterone and oestrogen. Goserelin works by acting on the pituitary gland in your brain to stop the production of some of the sex hormones your body makes.

It's used for many conditions including:

  • Endometriosis: To reduce symptoms, including pain and the size and number of endometrial deposits.
  • Uterine fibroids: Before surgery to reduce the size of the fibroids and symptoms including pain.
  • Breast cancer: To reduce oestrogen production in people who have oestrogen receptor positive  (ER positive) breast cancer, who are pre- or peri menopausal. 
  • Prostate cancer: To reduce or stop testosterone production which slows the growth of cancer or shrinks it.
  • Fertility treatment: To encourage ovulation. 
  • Gender affirmation: As a puberty blocker, to temporarily suppress the physical changes of puberty, eg, breast development or facial hair.

December 2023: The funded brand of goserelin is changing

From December 2023, a new brand of goserelin, Zoladex will be funded. Zoladex has the same active ingredient and works the same way as Teva-Goserelin. Find out more about the brand change: goserelin injection [PDF, 299 KB]

Goserelin is given as an injection

  • Goserelin injection comes as a small pellet (called an implant) about the size of a grain of rice, which releases the medicine slowly into your body over time.
  • The injection is given just under the skin of your tummy (abdomen) by your doctor or nurse.
  • The implant will completely dissolve over weeks or months.

In Aotearoa New Zealand goserelin injection is available in 2 strengths

  • Goserelin injection is available in 2 strengths – 3.6 mg given every 4 weeks OR 10.8 mg given every 12 weeks.
  • Your doctor will choose the best dose for you and your condition.
  • Remember to book your next appointment in plenty of time so that you receive your injection when it's due.
  • If you miss an appointment for your injection, contact your healthcare provider as soon as possible.

Here are some things to know when you're using goserelin. Other things may be important as well, so ask your healthcare provider what you should know about.

  • Pregnancy: You shouldn't receive goserelin if you're pregnant, or think you might be. Goserelin is not a contraceptive and, even if your periods have stopped, you could become pregnant while you are having treatment. It's important to use a reliable barrier method of contraception, such as a condom. Don't use oral contraceptives ('the pill').
  • Pregnant: If you're using goserelin as a fertility treatment, you will have had a test to show that you're not pregnant before starting goserelin. Tell your doctor immediately if you become pregnant.
  • Bleeding: If you usually have periods, they will stop while you're using goserelin, but you might get some vaginal bleeding when you first start. Periods usually start again once you stop goserelin.
  • Cancer: People being treated for cancer can sometimes get a ‘tumour flare’ when they first start goserelin. This can cause new or worsening symptoms such as bone pain. Tell your healthcare provider if this happens to you.
  • Bone density: Goserelin can weaken your bones. You may need tests to check for this.
  • Blood glucose: Goserelin can affect your blood glucose levels. If you have diabetes you may need to check your blood glucose more frequently. Your healthcare provider will advise you about this.
  • Other medicines: Goserelin can interact with some medicines and herbal supplements, so check with your doctor or pharmacist before starting goserelin and before starting any new products.

Like all medicines, goserelin can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Stinging, pain, redness or bruising at the injection site
  • This will usually settle within a few days.
  • Tell your doctor if it bothers you. 
  • Headache, dizziness, tiredness or weakness
  • Tell your doctor if they bother you. 
  • Hot flushes and sweats
  • These are quite common when you first start goserelin and may continue for some time after you stop it.
  • Tell your doctor if they bother you. 
  • Less interest in sex (low libido)
  • Erection problems
  • Vaginal dryness
  • Sore or enlarged breasts
  • Tell your doctor if you are concerned.
  • Changes in mood, including low mood
  • Sleep problems
  • Weight gain
  • Tell your doctor. 
  • Signs of an allergic reaction such as skin rashes, itching, redness or swelling of the face, lips, mouth or have problems breathing.
  • Tell your doctor immediately or ring Healthline on 0800 611 116.
Did you know that you can report a medicine side effect to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product.(external link)

The following links provide further information on goserelin.

Goserelin(external link) NZ Formulary, NZ
Goserelin consumer medicine information(external link) Teva
Zoladex(external link) Medsafe consumer medicine information, NZ


Goserelin factsheet [PDF, 299 KB] PHARMAC, NZ, 2023 English [PDF, 299 KB], te reo Māori [PDF, 388 KB], Samoan [PDF, 304 KB]
5 questions to ask about your medications(external link) Health Quality and Safety Commission, NZ, 2019 English(external link), te reo Māori(external link)


  1. Goserelin(external link) NZ Formulary, NZ

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