The BCP I take, called Qlaira, is unusual as it's very similar to HRT. It's bio identical and is a low dose so the only real difference is you take progesterone almost everyday and also it's a contraceptive. With conventional BCPs, the main difference is they stop you ovulating, so they replace your own hormones, rather than just topping them up as HRT does. Conventional pills have a more potent form of estrogen (which some doctors say is what's needed for younger ladies with fluctuating hormones). Hope that makes sense? It took me a while to understand the difference. In fact, I'd always assumed HRT was stronger until I spoke to the consultant.