Millions of women may be reaching for the incorrect pain relief for menstrual cramps, according to a new study analyzing over 211 million receipts. The research found that paracetamol was the most frequently purchased painkiller alongside tampons and sanitary towels.

Experts, however, suggest that ibuprofen might be a more suitable option for many women experiencing period pain. Ibuprofen is an anti-inflammatory drug that is considered more effective at treating the muscle cramps associated with menstruation. This is because it works by blocking the production of prostaglandins, hormone-like substances that cause the womb muscles to contract. Paracetamol, in contrast, primarily acts in the brain to block pain signals and is typically recommended for headaches.

The study, published in PLoS Digital Health, analyzed data from 3.1 million shoppers between 2006 and 2015. It revealed that half of all transactions involving menstrual products also included a pain relief purchase. Of these pain relief products, approximately two-thirds were paracetamol-based, with the remaining third being ibuprofen.

According to NHS guidance and the charity Endometriosis UK, starting ibuprofen the day before or several days before expected period pain can be beneficial, as it can help prevent the body from producing high levels of prostaglandins. Cramping is a normal part of the menstrual cycle when the uterine muscles contract to help shed the lining. However, higher levels of prostaglandins have been linked to more severe menstrual cramps.

Survey data indicates a significant prevalence of period pain. Researchers estimate that seven in ten British women experience debilitating period pain for approximately four years of their lives. Furthermore, 78 percent of these women have been told by a medical professional that monthly discomfort is normal. A separate survey of 5,000 women found that the average sufferer experiences three days of pain per month, totaling 1,350 days over 450 periods. Among these, 9 percent describe their pain as excruciating, 24 percent as an intense, sharp, stabbing feeling, and 47 percent find their periods particularly debilitating, with 31 percent calling them unmanageable and 48 percent reporting a lack of energy.