I've been out on the web, found lots of reports of similar niacin-menstrual influences; but no theories about why it would happen.

However, it has been acting on me like a hormone regulator. Appetite steadier, so blood sugar more stable? I have a tad more energy, so either my cortisol resistance is being lowered (letting cortisol into the cells where it belongs) or I am actually making more adrenal hormones, perhaps?

If it is a weight loss help, I will soon find out