GnRH medicines are sometimes discussed for people with endometriosis symptoms. They work by temporarily lowering ovarian hormone activity, which can reduce oestrogen levels and may reduce symptoms for some people.

They should be explained carefully before starting because they are not cures, they do not remove endometriosis lesions, and side effects and monitoring matter.

What GnRH means

GnRH stands for gonadotrophin-releasing hormone. GnRH is involved in the hormone signals between the brain, pituitary gland and ovaries. GnRH medicines change this signalling so ovarian hormone activity is reduced for a period of time. This can create a temporary low-oestrogen state. Some people describe this as a menopause-like or “medical menopause” effect.

GnRH agonists and GnRH antagonists

There are different types of GnRH medicines. GnRH agonists initially stimulate GnRH receptors before suppressing hormone signalling over time. Examples include medicines such as leuprorelin, goserelin or nafarelin. GnRH antagonists block GnRH receptors more directly. Some newer options are taken by mouth and may be used with hormonal add-back therapy in selected patients. The exact medicine, dose, duration and monitoring plan should be explained by a healthcare professional.

How they may be used

GnRH medicines may be discussed in selected situations, such as when:

  • symptoms continue despite other hormonal treatment
  • other options are not suitable or not tolerated
  • symptoms are significantly affecting daily life
  • treatment is being considered after medical or surgical care
  • deep endometriosis is suspected or confirmed
  • short-term treatment is being considered before planned surgery

They are not right for everyone, and they should not be offered as a general answer to all pelvic pain without a clear reason and review plan.

What they may help with

GnRH medicines may help reduce:

  • period-related pain
  • pelvic pain
  • cyclical symptom flares
  • bleeding for some people
  • pain linked with hormonally responsive symptoms

They may help some people function better while taking them, but response varies. Some people do not get enough relief, and some stop because of side effects.

What they do not do

GnRH medicines do not cure endometriosis. They do not physically remove:

  • endometriosis lesions
  • adhesions
  • scar tissue
  • endometriomas
  • deep disease
  • bowel, bladder, diaphragm, thoracic or nerve-involving disease

Symptoms may improve while taking treatment and return after stopping. This is why it is important to understand the purpose of treatment and what the next step will be.

Side effects

Because GnRH medicines reduce oestrogen levels, they can cause menopause-like side effects. These may include:

  • hot flushes
  • night sweats
  • mood changes
  • anxiety or low mood
  • sleep problems
  • headaches or migraines
  • vaginal dryness
  • reduced libido
  • fatigue or low energy
  • dizziness
  • joint or muscle aches
  • changes in bowel function
  • bone density concerns, especially with longer use

Side effects should not be brushed aside. Ask what is expected, what is concerning, and how side effects will be reviewed.

Bone health and treatment length

Low oestrogen can affect bone density. This is one of the main reasons treatment length and monitoring matter. Before starting, ask:

  • How long will I be on this medicine?
  • Is there a maximum recommended duration?
  • Do I need bone health assessment?
  • Do I need vitamin D, calcium advice or lifestyle guidance?
  • What risk factors do I have for bone thinning?
  • What happens if symptoms return after stopping?

Add-back therapy may be recommended for some people at increased risk of bone thinning.

Add-back therapy

Add-back therapy means giving a small amount of hormone alongside a GnRH medicine to reduce low-oestrogen side effects and help protect bone health. It may help reduce symptoms such as hot flushes, sleep disruption, vaginal dryness and bone density loss. Ask:

  • Will I need add-back therapy?
  • What type of add-back is recommended?
  • When would I start it?
  • What side effects could it cause?
  • How will we know whether it is working?

Add-back decisions should be personalised.

Fertility and pregnancy plans

GnRH medicines are not fertility treatments and are not suitable if you are pregnant or trying to become pregnant during treatment. If fertility matters to you now or in the future, say this before starting. Ask:

  • Can I become pregnant while taking this medicine?
  • Do I need contraception during treatment?
  • How soon might cycles return after stopping?
  • Could this delay trying to conceive?
  • Should fertility advice be considered before treatment?
  • Is this the right option if I want pregnancy soon?

Informed consent matters

GnRH medicines may be appropriate for some people, but they should only be started after a clear discussion. You should understand:

  • why the medicine is being suggested
  • what it is expected to help
  • whether it is an agonist or antagonist
  • whether it manages symptoms or supports another treatment plan
  • what it cannot do
  • likely side effects
  • serious risks
  • treatment length
  • add-back therapy
  • monitoring
  • alternatives
  • what happens if symptoms return

You are allowed to ask for time to think before deciding.

When GnRH is not enough

Ask for review if:

  • symptoms do not improve
  • side effects are difficult
  • mood changes are significant
  • pain returns quickly
  • symptoms worsen after stopping
  • bowel, bladder, chest, diaphragm or nerve symptoms continue
  • fertility priorities change
  • you are unclear why treatment is being used
  • you feel treatment is delaying investigation or specialist referral

GnRH medicines should not be used to avoid proper assessment when symptoms are severe, persistent, complex or affecting daily life.

Questions to ask

You may want to ask:

  • Why are you recommending this medicine?
  • Is it a GnRH agonist or antagonist?
  • What symptoms is it expected to help?
  • Does it treat disease or manage symptoms?
  • What side effects should I expect?
  • What side effects need urgent advice?
  • Will I need add-back therapy?
  • How long can I use it?
  • What monitoring is needed?
  • How will bone health be protected?
  • What happens when I stop?
  • Could symptoms return?
  • What are the alternatives?
  • Will investigation or referral continue if symptoms persist?

Prepare before you speak with a healthcare professional

Use our Prepare for Appointment Tool to organise your symptoms, previous treatments, side effects, fertility priorities, questions and concerns before your appointment. You do not need a perfect diary. A clear summary of what is happening and how symptoms affect your life can help the conversation feel more focused.

Final reminder

GnRH medicines may help symptoms for some people, but they are not a cure for endometriosis and they can have significant side effects. This does not mean they are never the right option, but they should only be started after clear discussion of the potential benefits, risks, side effects, alternatives, expected duration and review plan, so you can make an informed decision. This resource is here to support your understanding, not replace medical advice from a qualified healthcare professional.