HRT side effects

Starting hormone therapy usually comes with some adjustment, and NICE guideline NG23 builds a specific review process around that expectation, rather than leaving you to simply wait and see.

Bleeding changes: expected, within limits

The side effect NICE addresses most specifically is bleeding. For people with a uterus taking combined HRT:

• Vaginal bleeding is a common side effect during the first 6 months of taking systemic HRT
• It's also common within 3 months of changing the dose or type of HRT
• Beyond those windows, unscheduled bleeding should be checked promptly by a doctor — see bleeding after menopause if you're already past the 12-month menopause mark

Other commonly reported effects

Breast tenderness, nausea, bloating, and headaches are commonly reported when starting HRT or adjusting a dose, and tend to ease as your body adjusts. These vary a lot by individual and by formulation and route, which is one reason the standard approach is a structured review rather than guessing — see patch vs. pill and types of HRT for how switching route or formulation can sometimes address a specific side effect.

The review schedule that's built around this

NICE recommends reviewing any menopause treatment:

• At 3 months, to check how well it's working and how you're tolerating it
• Annually after that, unless there's a specific reason to review sooner — such as the treatment not working, side effects, or an adverse event

If side effects persist past your 3-month review, or symptoms simply aren't improving, NICE recommends being referred to a healthcare professional with menopause expertise rather than just continuing on the same plan.

Track what you're experiencing

Logging side effects and their timing in our private symptom tracker gives you something concrete to bring to your 3-month review, rather than relying on memory. If a side effect makes you want to compare non-hormonal options too, see our Does It Work? evidence directory.