Study: Many Women Buy Wrong Painkiller for Cramps

The difference lies in how the two drugs work. Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID) that reduces swelling and lowers prostaglandins — the hormone-like chemicals that trigger the contractions of the womb muscle responsible for cramping. Higher levels of prostaglandins have been linked to more severe pain. Paracetamol, by contrast, acts mainly in the brain to block pain signals and to reduce fever, making it well suited to headaches or flu, but it lacks anti-inflammatory properties. The charity Endometriosis UK advises starting ibuprofen a day or more before a period is expected, before the body produces prostaglandins. Researchers suggest paracetamol may simply be more familiar, which could explain why shoppers reach for it more often.

Investigators said the findings expose how little period pain has been studied. Professor James Goulding of Nottingham University told the BBC, 'if men got period pain, we'd know a lot more about it by now,' calling the results a public health education opportunity. Co-researcher Dr Anya Skatova of Bristol University cautioned that the data — drawn from between 3.1 and 3.4 million shoppers — offers a snapshot rather than a fully representative national picture. Separately, survey data suggests that seven in ten British women endure debilitating period pain, averaging three painful days each month. The NHS advises anyone whose cramps disrupt daily life to see a doctor, as severe pain can signal conditions such as endometriosis or fibroids.