The best one ive taken is Mega Men by GNC...they make a womens formula as well...Womens Ultra Mega...These are specially formulated for a man and a womans body....There all natural and higher potency....there 21.99 second half price...Twinlab is good to, however there are synthetic forms in the Twinlab multiple...but its still really good. GNC is more expensive than buying the stuff wholesale on the internet....but theres no shipping charge and you get the stuff today.