I found a chart comparing potency of methylfolate brands. I don't know if it's accurate or not, but the person who created it explains their reasoning in the link below: http://www.methyl-life.com/methylfolate-types.html One thing I should mention is that the person who created the chart is selling Quatrefolic and yet they still say Metafolin is more potent. They do provide a chart at the bottom claiming that their Quatrefolic product is still the best value due to the lower price. Their chart (the one about prices and not the one I posted here about potency) is inaccurate however. First, Solgar's Metafolin is $1.00 less than the price they say it is. On top of that, Pureformulas, Swanson, iHerb, and Vitacost have a lot of sales and/or free shipping offers so buying Solgar's Metafolin there would be the most cost effective. Right now Pureformulas would be the best place to order it. They have free shipping in the US for any size order and a 10% off offer if you use NEXT10. You can also check retailmenot.com for a referral code to use when you sign up for pureformulas that will give you an additional $5.00 in points that can be redeemed at any time. The other stores also have a lot of coupons and sales that can be found at retailmenot. Pureformulas is selling a b complex with Metafolin from Douglas Labs. Swanson is also selling an active B complex with Quatrefolic that is a better deal because it higher dosages of B vitamins including 50 mg of both P5P and R5P (this dosage might be too high for some people though). Even the Douglas Labs with 400 mcg of methylfolate and less P5P and R5P might be too much for some people.