Using just 1.5g per day of cinnamon has been found to improve cycle regularity in women with PCOS. In 2014 a prospective double blind randomised placebo controlled trial had 2 groups of women with PCOS, one group took a placebo and the other group took 1.5g cinnamon per day. Over 6 months the women from both groups recorded their menstrual cycles and had their blood progesterone levels taken. The researchers found that the women taking the cinnamon had more regular menstrual cycles compared to the placebo group who did not have any change in their cycle regularity. They also confirmed ovulation in the women taking cinnamon via blood progesterone levels.
Based on the study mentioned if you added about ½ teaspoon of cinnamon to your diet per day then you should notice an improvement in cycle regularity within 3-6 months. Cinnamon can be added to smoothies, porridge, yoghurt, chia puddings plus many more.
Kort DH1, Lobo RA1. 2014 “Preliminary evidence that cinnamon improves menstrual cyclicity in women with polycystic ovary syndrome: a randomized controlled trial.” Am J Obstet Gynecol. 2014 Nov;211(5):487.e1-6.