I just got back from a conference where a poster was presented showing that chronic oral administration of glutamine decreased the absorption into the blood stream via glutamine transporter down-regulation (much the same as chronic high dose vitamin C does to vitamin-C absorption). The implications of this for BBs is not clear since no one has really shown a benefit from oral glutamine in otherwise healthy and well fed folks on a high protein diet. However IF you wish to take glutamine "just in case", it would seem prudent to cycle it just like most other supps......