Possible Side Effects Of Hormone Replacement Therapy (HRT)

What can you do to manage HRT side effects?

Last reviewed: 10 Mar 2019

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Contents of this article

Hormone replacement treatment (HRT) has a lot of benefits, but side effects are possible too. The chance of side effects varies between different HRT methods so it's good to look into it before starting treatment.

Learn the possible side effects of HRT, and learn what to do about them. Stopping HRT altogether might not be the best place to start...

Can HRT give me side effects?

Yes – there's a chance that HRT will give you side effects. The most common side effects HRT can give women are:

  • Breast tenderness
  • Nausea
  • Headaches
  • Bloating
  • Depression
  • Irritability

Bleeding – irregular vaginal bleeding/spotting is also common in the first 3-6 months on HRT. It often improves with time. You should discuss any bleeding with your doctor, as this may need investigating depending on what HRT you are taking, what the bleeding is like and when you last had a bleed prior to HRT.

What should I do if I get side effects? – most often these are mild, and improve with time. Sometimes this is a reason to change the type of HRT you are taking, either the dose or the formulation.

Should I stop my HRT if I get side effects? – it is good advice to stick with your current HRT for 3 months to see if side effects improve, rather than making rapid changes.

Can I tell if I will I get side effects? – as long as a doctor has approved HRT treatment for you, it’s not easy to predict if you will get side effects. Many women start HRT, feel better very quickly and don’t have side effects at all.

Can I do anything to avoid side effects? – in general the following list are tips for minimising side effects:

  • Take HRT as it has been prescribed, at the correct times of day, and don’t miss out tablets or forget to change your patches on time
  • Follow a healthy lifestyle – quit smoking, eat a healthy diet, drink alcohol within recommended limits, and take regular exercise
  • Maintain a healthy BMI (21-25)

Take self help measures to minimise HRT symptoms such as:

  • Avoid caffeine after 6pm
  • Avoid spicy foods/any food or drink that initiates a hot flush
  • Keep the bedroom cool
  • Wear thin cotton layers
  • Generally you will sleep better if you have dim lighting and no electronic devices in the bedroom such as no TVs, laptops or smartphones

Will I gain weight on HRT?

HRT doesn't cause weight gain – there is no medical evidence to support the idea that HRT causes weight gain.

If you're gaining weight around the time of your menopause this could be a natural result of aging – as we age our metabolic rate slows and we burn calories much less efficiently. There is a natural redistribution of body fat, to deposit this around the abdomen rather than on the hips. This is part of a natural ageing process.

We also start to lose muscle mass. As the muscle mass goes down, this reduces the metabolic rate further. Doing exercise and building muscle is an important way to help maintain your weight and health.

How can HRT help me avoid weight gain related to menopause? – HRT could indirectly make it easy to manage your weight:

  • Within a few weeks/months of starting you should find your hot flushes and night sweats are much improved
  • As a result, you could be sleeping better, have more energy, and feel more like your normal self
  • Having more energy and feeling better, should help you be able to address your diet and fitness
  • Combined with a proper diet and fitness regime, this should help you feel better, and could aid weight loss

HRT is only one part of the process of dealing with your menopause. You can do more to improve your energy levels, diet, and fitness.

How can I manage my weight during menopause? – there is no quick fix for weight management:

  • To lose weight you need to take in less in calories through food, and expend more calories during the day, especially by exercise
  • If you are overweight (BMI >26) you can discuss this with your GP/practice nurse
  • There are ways to support your weight loss plans, such as weight loss medications like Xenical or Orlistat. You should always discuss this with your doctor before starting them

Which HRT will give me the least side effects?

The following list shows which methods of HRT have more or less risk of side effects:

Less risk:

  • ‘Continuous’ HRT
  • Oestrogen only
  • Vaginal tablets

More risk:

  • ‘Cyclical’ HRT
  • Combined oestrogen and progesterone
  • Oral tablets

Oestrogen with or without progesterone? – in general there are less possible side effects with oestrogen-only HRT, than with HRT that also contains progesterone:

Oestrogen-only HRT side effects include:

  • Nausea
  • Headache
  • Breast Tenderness

Oestrogen and progesterone combined HRT include the side effects above, plus:

  • Depression
  • Irritability – similar to having premenstrual syndrome
  • Bloating

Oestrogen-only HRT oral tablets and patches are only meant for women who’ve had their womb removed – if you have not had your womb removed then you need to take both oestrogen and progesterone, or use oestrogen-only vaginal tablets. Oestrogen without progesterone can overstimulate the lining of the womb (the endometrium), giving a small increased risk of endometrial cancer. With vaginal tablets, the oestrogen does not reach the womb as easily so you don’t need progesterone as well.

Vaginal tablets, oral tablets, or patches and gels?

  • Vaginal tablets are the least likely to give side effects because they don’t enter the bloodstream as much (unlike oral tablets or patches)
  • Some women may find they have less side effects with patches and gels rather than oral tablets. This is thought to be because when using a patch, the hormones are being absorbed directly through the skin into the bloodstream
  • With oral tablets, they have to be swallowed and absorbed in your stomach which can cause digestion problems

‘Continuous’ or ‘cyclical’ – ‘continuous’ HRT treatment is less likely to cause bleeding-related side effects than ‘cyclical’ treatment. This is because they work slightly differently:

  • Continuous treatment – this is where you continue taking progesterone throughout your month cycle of HRT
  • Cyclical treatment – this is where you only take progesterone for part of the cycle. You stopping taking it for 2 weeks during each month of HRT

Are there menopause treatments other than HRT that are less likely to cause side effects? – yes but none of them work as well as HRT and they won’t necessarily have less side effects. They include:

  • Other medications
  • Cognitive behavioural therapy (CBT)
  • Herbal treatments

Please note – the main reason to consider HRT first is it also protects against the risk of osteoporosis that increases with menopause

Other medications – there are other medications that can treat menopause too. They may not work as well as HRT and come with their own risk of side effects, which could be better or worse. They include:

  • Some antidepressants – Selective Serotonin Reuptake Inhibitors (SSRI), including (fluoxetine, paroxetine, citalopram, sertraline) and the Serotonin Noradrenaline Reuptake Inhibitor/Selective Serotonin Reuptake Inhibitors (SSRI-SNRI), including venlafaxine which works to improve hot flushes and also any menopause-related (or non-menopause-related) depression or anxiety. SSRI’s can also have side effects such as dizziness, dry mouth, constipation and reduced libido
  • Gamma aminobutyric acid (gabapentin) – this is a drug used to treat epilepsy. It can be used to treat hot flushes, but may cause drowsiness. Some people like this as it may help them to sleep. However there may be side effects such as a dry mouth, dizziness and weight gain
  • Clonidine – this is a drug that is usually prescribed for high blood pressure but there is some medical evidence that it can improve hot flushes and night sweats

CBT – there is now good medical evidence to support the use of CBT to help alleviate menopausal symptoms. This treatment relies on a good understanding of menopause, relaxation techniques, better sleep and a positive mental attitude. You may be referred for CBT by your doctor, or you can purchase a CBT guide to do this at home. CBT does not have side effects like a medication does

Herbal treatments – there are some herbal supplements that may improve menopause symptoms. They are likely to be less effective than HRT, or they won’t work at all. They may or may not cause side effects even though they aren’t medication:

  • St John’s Wort – although this may help reduce hot flushes, it may interact with other medicines. St John’s Wort is not recommended for patients on tamoxifen as it can stop tamoxifen from working. If you’re taking St John’s wort, it’s important that you inform your doctor before you start a new treatment.
  • Black cohosh (Cimicifuga racemosa) – this is one of the most frequently used herbal therapies for hot flushes. However, recent studies have not proven its efficacy, and there is very little known about its safety in clinical use. It may interact with other medicines. There have been anecdotal reports of liver failure
  • Isoflavones and red clover – these are plant oestrogens called ‘phytoestrogens’ which have oestrogenic effects in plants. They are found in high quantities in some foods, for example chickpeas, beans, soy beans, and tofu
  • Progesterone cream – although this contains the hormone progesterone, it has not been shown to work for menopause symptoms

What should I do if I think I’m having HRT side effects?

What to do first – talk to your doctor. They will be able to check if your side effects are serious or not and can give you advice about what to do.

Waiting them out – most HRT side effects are mild and they get better the longer you take your treatment for. If they aren’t serious, then it might be a good idea to wait and see if your side effects improve

When should you stop taking HRT right away?

  • If you are acutely unwell, such a heart attack, stroke, thrombosis, or a new diagnosis of breast or endometrial cancer
  • If you become jaundiced or your liver functions abnormal
  • If you have a sudden increase in blood pressure
  • If you have a new onset of migraine/headache, having never had this before
  • If you become pregnant
  • If you have an acute allergy to HRT or one of its constituents

When to get emergency help (call 111 or 999) – if you experience signs of an serious allergic reaction (anaphylaxis), such as:

  • Chest tightness/difficulty breathing
  • Swelling of the face/lips and tongue
  • Rash – urticaria
  • Dizziness, confusion, or loss of consciousness

Are there any other risks to HRT?

As well as side effects there are also risks to HRT treatment. These include:

  • Health risks to certain people which mean they can’t have HRT
  • Potential increased risk of some other health conditions, including breast cancer, heart disease and stroke, blood clots
  • Mistakes that you can make when using HRT

You should talk to your GP about these risks when deciding whether HRT is right for you.

Health risks that make HRT unsafe – as long as you’ve had an assessment from your doctor before getting treatment you don’t need to worry about this because they will check for these risks and they wouldn’t approve treatment if there was a problem. Health risks would include preexisting conditions such as some cancers or conditions affecting your heart or circulation.

Risk of breast cancer – there’s an increased risk of breast cancer on HRT. The Medicines and Healthcare products Regulatory Agency (MHRA) released a report in August 2019 with findings from new studies on these risks. These show that the risk is higher than originally thought. The MHRA's patient information leaflet covers this in more detail.

This is something that you should talk to your GP about at your next annual review. If you have any questions about this in the meantime, you can message our doctors through your account. They’ll be happy to answer any concerns you may have. You should also make sure that you’re going to your national breast cancer screening appointments, and do the breast cancer self-checks as well.

Risk of heart disease and stroke – there is actually no proven increase in the risk of cardiovascular disease (heart attacks or strokes) for women on HRT when it is started before 60 years old. However, these risks increase anyway as you get older.

Blood clots – there is an increase in the risk of blood clots for women on HRT. This might be more related to tablets than patches, and mostly affects women who already have an increased risk of blood clots before HRT.

Common mistakes when using HRT:

  • Missing doses – missing doses here and there won’t cause too much trouble but you may not have the best treatment effect, especially if you miss too many
  • Overdosing – avoid any more of your HRT than you should. This can cause you to feel very sick
  • Not timing your bleed correctly (cyclical HRT only) – your bleed should happen when you start a new pack of your HRT. If it happens at other times you should talk to a doctor
  • Not changing patches at the right time (patches only) – you need to know how often they need changing and make sure you do it at the right time and in the right way. You should remove the old patch first and apply the new patch to clean dry skin
  • Swimming or sunbathing right after applying gel (gel only) – you need to wait for your gel to be absorbed first before doing these activities

What are the side effects of stopping or not using HRT?

The risk of osteoporosis – osteoporosis is a serious bone problem that can be brought on by menopause. 1 in 2 women over 50 will have an osteoporotic fracture and 3 million people in the UK are living with osteoporosis, a debilitating disease. Of those who fracture a hip for example, there is a 20% chance of death. Taking HRT will reduce your chance of an osteoporotic fracture by approximately 50%.

The HRT-related benefits:

  • Less hot flushes/night sweats (5% of women have hot flushes for life)
  • Better bone mineral density (BMD) – treats osteoporosis
  • Reduction in the risk of type 2 diabetes
  • A positive effect on collagen, the main constituent of skin, nails and hair, and of cartilage in joint spaces such as intervertebral discs, and helps joint pains
  • Improved symptoms of anxiety and depression
  • Reduced insomnia (sleeping problems)
  • Reduced vaginal dryness
  • Better tone of your pelvic floor which can help urge incontinence (bladder control) and reduce recurrent urinary tract infections
  • Better sexual function
  • Less problems with dry eyes
  • Possible protection against the onset of Alzheimer's and colonic cancer

Can you try HRT for a short time and then stop again? – you can do this, particularly if you’re worried about side effects. Remember that side effects may appear but they’re usually mild and go away over time. We recommend that you take treatment for at least 3 months, as long as you don’t have any serious side effects.

You can try more than one HRT method to find one that suits you – although this might take time and effort, it’s better than sticking with a treatment where you aren’t happy with the side effects.


British Menopause Society (2011). Risk of recurrent thrombosis affected by type of HRT. BMS. [online] Available at: https://thebms.org.uk/2011/05/risk-of-recurrent-thrombosis-affected-by-type-of-hrt/ [accessed 19th January 2018].

Johnston, J. (2015). Diet, exercise & lifestyle: weight gain. Menopause Matters. [online] Available at: https://www.menopausematters.co.uk/weightgain.php [accessed 19th January 2018].

Meda Pharmaceuticals (2016). Elleste Solo 2mg. EMC. [online] Available at: https://www.medicines.org.uk/emc/medicine/20966 [accessed 19th January 2018].


Dr Laura Joigneau Prieto joined Zava in April 2018 as a clinical doctor. She studied medicine at the Universidad Autónoma in Madrid, Spain, and at the Pierre and Marie Curie Faculty in Paris, France. She did a Master’s Degree in clinical medicine in 2009 at the Rey Juan Carlos University in Madrid.

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Last reviewed: 10 Mar 2019

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