If you follow American Metabolix, you’ll most likely be familiar with its always impressive flash sales. We’ve posted about a couple of them here in the past, one of which has been brought back again this week. The deal the brand has launched for a second time is 3.8lb of the Stack3d Certified Premium Whey for $49. To take advantage of the offer all you need to do is add the supplement to your cart at americanmetabolix.com, and use the code “WHEY49”. Premium Whey will then be discounted $21, dropping it to the promised $49. Even if you don’t want any protein it is well worth heading over to the site anyway as the coupon does appear to be working on everything, dropping a number of products to just $4.