I found this online, hope this helps!
IMMUNOCAL is “food for your immune system” and ideally should be eaten on an empty stomach, so first thing in the morning works well for most people. It is absorbed through the lining of the stomach; goes into the intestines; then into the blood stream. This is where the precursors that help your body make more glutathione are delivered to all the cells. Having a meal in the stomach interrupts this process. You can eat a meal 30-45 minutes after taking IMMUNOCAL. If you need to take IMMUNOCAL later in the day (some people take a second dose before bedtime), make sure your stomach is mostly empty. As long as you haven't eaten anything for about 3 hours, there's probably not much food left in the stomach. It is best not to mix IMMUNOCAL with milk or another protein source, because taking it with another protein could possibly inhibit the absorption of this specially processed whey protein isolate.
IMMUNOCAL is most effective when prepared in water or juice (2-4 ounces of liquid per packet is advised; you can adjust the desired consistency; it is perfectly OK to take 2 or 3 packets at one time). If you use water, then fresh (not tap) is recommended. Some stores carry a brand of bottled water called PROPEL, which has a natural sweetener added to it. Or, you can use regular bottled water and sweeten it with just a few drops of liquid STEVIA (this is a naturally sweet herb you can buy at a health food store; it is also available in powdered form). Keep in mind you do not need to add any sweetener to your fresh water unless you prefer it that way.
FYI: The 2 juices you should not mix with IMMUNOCAL are cranberry (or a cranberry blend) and pineapple (cranberry is too acidic and pineapple has enzymes). Both juices destroy the bioactivity, which is very fragile. All other juices are OK, including orange juice and other citrus. (Please note: If you are taking enzymes to help with a pre-existing digestive problem, do not take them at the same time as IMMUNOCAL. Wait at least 1 hour before taking your enzymes.) Drink your prepared IMMUNOCAL within 30 minutes. If you leave it sitting around longer, the bioactivity is destroyed, which renders IMMUNOCAL ineffective.
Heat also destroys the bioactivity, so never mix IMMUNOCAL in a household blender or anything with metal bladesbecause the high speed creates heat. Never use any liquid warmer than room temperature. Do not drink a hot liquid, like coffee or tea, immediately before or after consuming IMMUNOCAL. It is not recommended to leave the boxes or individual packets sitting in the hot sun, or in the heat of a car.