In healthy individuals, approximately 20 percent of an oral dose of DMSA is absorbed from the gastrointestinal tract. Ninety-five percent of the DMSA that makes it to the bloodstream is bound to albumin. One of the sulfhydryls in DMSA binds to a cysteine residue on albumin, leaving the other S-H available to chelate metals. In healthy fasting men, 90 percent of the DMSA recovered in the urine was found to be mixed disulfides (where DMSA is attached to one or two cysteine molecules), and 10 percent was free unchanged DMSA. No mixed disulfides were found in the blood. It is thought these disulfides are formed as albumin releases DMSA in the kidneys.
There is no question that DMSA is more readily absorbed when it is taken on an empty stomach. However, some people experience gastric upset when they take DMSA apart from food, and that is more likely to occur in children. Therefore, caution and flexibility are required in regard to this.