Thiamine di(2-methylpropionate) disulfide: This modified version of the [B.sub.I] vitamin thiamine works selectively on the brain. Thiamine is known to play a key role in normal nervous-system function and carbohydrate metabolism. Many scientists believe that taking supplemental thiamine can enhance the nervous system by improving memory and recall as well as boosting control of muscle activity. Taking extra thiamine is also thought to augment carbohydrate metabolism as it increases muscle endurance during short bouts of intense activity. That means thiamine may be able to help you complete more reps with a given weight and offer you more overall energy. Yet despite its potential, regular thiamine is poorly absorbed by the digestive system). But modified versions such as thiamine di(2-methylpropionate) disulfide not only enhance absorption but also function. This modified thiamine selectively binds to specific cells in the brain. This means it activates certain areas of the brain and causes them to stimulate motor activities and motivation.