The very first thing any woman with PCOS needs to do to stop PCOS-related hair loss is to control blood sugar levels. High blood sugar levels are what make the ovaries overproduce testosterone. High testosterone levels "turn off" the growth and renewal cycle in hair follicles in the scalp, but they "turn on" this same process where hair is not needed. Just avoiding sweets and losing as little as 2 to 5 per cent of total body weight will help. Avoiding further weight gain helps, too.
The second line of treatment for PCOS hair loss is metformin. This drug is one of the safest and least inexpensive treatments for PCOS and also for type 2 diabetes. This medication not only lowers blood sugar levels, it keeps a woman's body from making testosterone from a compound called androstenedione. Diet and metformin, however, are better for prevention than for cure. Restoration of lost hair requires other interventions. The most effective medication for the most women with PCOS hair loss is flutamide, also sold as Eulexin. This drug doesn't stop the production of testosterone. That's what diet and metformin do. Flutamide makes tissues insensitive to testosterone so that hair loss stops and hair has a chance to grow back in.
There are two things it is essential to know about flutamide. One is that it must not be used if there is a possibility of pregnancy, since it can cause severe hormonal imbalances lasting through all of life for the unborn child. The other thing to know about flutamide for PCOS hair loss treatment is that it probably most effective for women whose testosterone levels have returned to the "normal" range. Restoring hair loss seems to require getting testosterone below the levels that caused the hair loss in the first place. Results will almost certainly take months, but tiny and then more visible hairs eventually come back in.