HRT side effects: what's normal, how long they last, and weight gain
Most side effects of HRT are mild and settle within about 3 months. Many can be fixed by changing the dose, the type of HRT or how you take it. The best evidence shows HRT does not make you gain weight.
Speak to a GP if side effects are severe or last longer than 3 months, or if irregular bleeding lasts more than 6 months, gets heavier, or starts after your periods had stopped. Get urgent help for pain and swelling in one leg, chest pain, breathlessness or signs of a stroke.1,2
How common are side effects?
Many women have no side effects, or only mild ones. They usually improve over time, so it is worth carrying on for at least 3 months if you can.1
Side effects can look like menopause symptoms, so it is not always the HRT causing them. It can take time to find the dose and type that suit you.1
Side effects of estrogen
These can include headaches, breast pain or tenderness, spotting, feeling sick, mood changes, leg cramps, a mild rash or itching, diarrhoea and hair loss. They often go away after a few weeks.1
Side effects of progestogen
These can include changes in bleeding, headaches, breast tenderness, feeling sick, tiredness or dizziness, mood changes, a mild rash and acne.1,2
Some women feel low or irritable on progestogens. Changing to a different type, such as micronised progesterone or the hormonal coil, can help.3 See our page on progesterone.
Bleeding on HRT
Irregular bleeding or spotting is common in the first months of HRT and usually settles within 6 months.1
On sequential HRT, where you take progestogen for part of each month, a regular monthly bleed is expected. On continuous HRT, irregular spotting is common for the first 4 to 6 months.1
Tell your GP at your 3-month review if you have irregular bleeding. See them sooner if bleeding gets heavier or starts after a long gap.1
Does HRT cause weight gain?
No. A Cochrane review of trials found HRT had no effect on body weight.4 The NHS also says there is little evidence that most types of HRT cause weight gain.1
Many women do gain weight in midlife, whether or not they take HRT. Changes in muscle, sleep and activity all play a part. See our page on menopause weight gain.
Ways to ease side effects
- Give it time: most side effects ease within weeks to 3 months.1
- Ask about changing the route, for example from tablets to patches or gel.1
- Ask about a lower dose of estrogen, or a different progestogen.1,3
- For breast tenderness, a well-fitting supportive bra helps while it settles.5
Serious risks in context
Serious problems are rare. HRT tablets slightly raise the risk of blood clots and stroke, but patches, gels and sprays do not raise clot risk.6 HRT slightly raises breast cancer risk, depending on the type and how long you take it.6 See HRT and breast cancer risk.
Common questions
How long do HRT side effects last?
Most ease within a few weeks and usually by 3 months. Speak to a GP if they are severe or last longer.1
Can HRT make you put on weight?
The evidence says no. A Cochrane review found HRT had no effect on body weight.4
Is spotting on HRT normal?
Yes, in the first few months. It usually settles within 6 months. Tell your GP if it continues, gets heavier, or starts after your periods had stopped.1
Should I stop HRT if I get side effects?
Not without advice. Most side effects settle, and changing the dose, type or route often fixes them.1
Related
Sources
- Side effects of hormone replacement therapy (HRT), NHS
- Side effects of Utrogestan (micronised progesterone), NHS
- HRT: practical prescribing, tool for clinicians, British Menopause Society (amended August 2026)
- Kongnyuy EJ et al. Hormone replacement therapy has no effect on body weight and cannot prevent weight gain at menopause, Cochrane
- Side effects of HRT, Guy's and St Thomas' NHS Foundation Trust
- Benefits and risks of hormone replacement therapy (HRT), NHS