I started using Efamol Marine Evening Primrose Oil 10 years ago for M.E. which I suffer from, and it definitely helped with the joint pains but also I found that soon after using it, I no longer had awful breast pain at that time of the month each time, and that for me was a blessing. I used to have such tenderness that one time I used Deep Heat - would you believe! -but I was so desperate. Deep Heat is obviously no good for that by the way! But Efamol Marine Evening Primrose Oil is more suited to PMT pain than the ordinary Evening Primrose Oil. It is expensive, I think, at £9.99 for about a month's supply but for me it's worth it.