Tranexamic acid can reduce heavy menstrual bleeding, but it usually does not stop a period immediately or completely. It is meant for short-term use on the heavy-flow days, not to delay a period or treat unexplained bleeding.

Only take it if it has been prescribed or a pharmacist/clinician has confirmed it is suitable for you. Do not take it without medical advice if you have or have had a blood clot (DVT or pulmonary embolism), have kidney disease, epilepsy, irregular or unexplained vaginal bleeding, are pregnant or could be pregnant, or take estrogen-containing combined hormonal contraception, because clot risk may be higher. See the NHS safety guidance.

Seek urgent care now if you are soaking through a pad or tampon every hour for 2 or more hours, feel faint, have severe pelvic pain, might be pregnant, or develop chest pain, shortness of breath, or a painful swollen leg. Those last symptoms can indicate a clot, a rare but serious adverse effect described by the NHS.

If you tell me your age, whether this bleeding is unusually heavy or irregular, whether pregnancy is possible, and any contraception or clot history, I can help you assess whether it is likely safe to ask a pharmacist or clinician about.