Like any medicine, the hormones used in hormone replacement therapy (HRT) can cause side effects. But it's common to have no side effects or only mild ones.
Any side effects usually improve over time, so it's a good idea to carry on with your treatment for at least 3 months if possible.
Side effects of HRT can be similar to menopause symptoms. so it might not be your HRT that's causing a symptom.
There are different types of HRT. It can take time to find the right dose and type that works for you.
To help with side effects, your GP might suggest changing your dose, the type of HRT or how you take it. For example, switching from tablets to patches.
Non-urgent advice: Contact your GP if:
- you have severe side effects or they continue for longer than 3 months
Side effects of oestrogen
Side effects of taking oestrogen can include:
- headaches
- breast pain or tenderness
- unexpected vaginal bleeding or spotting
- feeling sick (nausea)
- mood changes, including low mood or depression
- mild rash or itching
- diarrhoea
- hair loss
They will often go away after a few weeks.
Find out more about side effects of oestrogen and how to cope:
Side effects of progestogen
Side effects of progestogen can include:
- changes in your periods, including spotting or bleeding between periods
- headaches
- breast pain or tenderness
- feeling sick (nausea)
- diarrhoea
- feeling tired or dizzy
- mood changes, including low mood or depression
- mild rash or itchy skin
- acne
As with side effects of oestrogen, these will usually go away after a few weeks. There are things you can do to help cope with them.
Side effects of Utrogestan (micronised progesterone) and how to cope
Side effects of combined HRT
If you take combined HRT you may get some of the side effects of oestrogen or those of progestogen.
Side effects of sequential combined HRT and how to cope
Side effects of tibolone
The common side effects of tibolone can include:
- breast tenderness
- stomach pain or pelvic pain
- unusual hair growth
- vaginal discharge, vaginal itching or thrush
- vaginal bleeding
- weight gain
Side effects of tibolone and how to cope
Vaginal bleeding and HRT
It's common to have irregular vaginal bleeding or spotting in the first few months after you start taking HRT. This usually settles down within 6 months and is not usually a sign of anything serious.
If you take sequential combined HRT, or daily oestrogen with separate progestogen tablets for part of the month, it's normal to have withdrawal bleeding at the end of each course of progestogen.
If you take continuous combined HRT, it's common to have irregular vaginal bleeding or spotting in the first 4 to 6 months.
Tell your GP at your 3-month appointment if you're having irregular vaginal bleeding. If it does not go away, the GP might suggest changing your dose of progestogen.
Non-urgent advice: Contact your GP if:
- you have irregular vaginal bleeding for more than 6 months after you start taking HRT
- your bleeding becomes heavier
- you get vaginal bleeding after you have not had periods for a while
- you have any bleeding after having sex
Weight gain and HRT
There's little evidence of weight gain with most types of HRT.
You may gain some weight during menopause and as you get older. But this often happens whether you take HRT or not.
Being active and eating a balanced diet can help you to manage your weight.
More serious risks
HRT has also been associated with a small increase in the risk of:
Report side effects
You can report any suspected side effects to the Health Products Regulatory Authority (HPRA): report an issue - hpra.ie