progesterone does favor girls when it is in the dw
here is more info i found...
Ok b6...
Originally we thought b6 was just to lengthen luteal phase. But I researched this a lot this weekend.
First of b6 does not effect pH. However it does effect progesterone (progesterone favors girls). Now some people who have really long cycles (38 days or more) tend to have a b6 deficiency. There are some great studies showing that these women take 25mg to 50mg of b6 a day from af to 0 have a normal cycle (less than 38 days). But for ttc a boy I would suggest the smallest amount because it would favor girls in that it helps with progesterone.
Next, women have been taking b6 50mg a day from af-af to help with luteal phase- to make it longer than 10 days. This is still true
Next, I found some info that says you can start b6 at 0 to af and it will help your progesterone and temps be high which can help with implantation. If you don't take b6 till O it will not sway toward girls. You would take 100-200mg of b6 from 0 to af but if you get a bfp you can't stop it cold turkey. You need to slowly get off of it.
B6 does have some side effects:
100-300mg can cause tingly hands and fingers and maybe drowsiness. These are reversed when you stop taking b6.
Stop taking b6 when you get a bfp can increase your risk of mc because it causes a sudden drop of progesterone. It is best to lower it slowly.
Taking it before O favors girls because it causes a rise in progesterone