Finding your whey
Whey and casein are the two main proteins in dairy foods: whey tends to be faster-digesting, casein is slower to break down. All protein sources provide the body with amino acids, the building blocks of the protein in your muscles, and for many people, whey is simply another type of protein that can add variety to the choices available. Whey is a common ingredient in many meal replacement and "refueling" products designed to provide maximum protein with minimal calories.
Some controlled trials suggest supplementing with whey supports better gains in lean body mass, some measures of strength, and better performance on short-term, intense cycling exercise, compared with people who use other protein supplements, such as casein.
The body best absorbs protein in amounts of 15 to 30 grams in a meal or snack. Unless you're a serious body-builder, there's no benefit to eating more than 30 grams of protein at one time. Whey protein seems to make its way into muscles most efficiently when taken immediately after a workout. Recommendation: ideally within 30 minutes, 1 gram of whey protein (up to 30 grams total) for every 2 to 4 grams of carbohydrate.
Whey protein is considered safe for most people, though people with dairy allergies should avoid it.
Creatine is found in many tissues in the body, and is best known for supplying energy for muscles during short, intense bursts of exercise, such as sprinting or weight lifting. Creatine may improve muscle mass, rather than muscle efficiency, so it's not taken by most endurance athletes. It may be used in an initial "loading period" of up to 20 grams per day for several days, followed by smaller amounts of 2 to 5 grams daily long term.
Numerous controlled trials support that creatine improves performance of single or repetitive bouts of short-duration, high-intensity exercise lasting under 30 seconds each, suggesting it may be most beneficial for people engaging in speed and power training regimens. While some controlled trials do not show benefit of creatine supplementation, health experts have noted this may be because elite athletes do not benefit from creatine supplementation, while untrained people do.
Creatine appears to be safe for most people, though it has been linked to individual cases of kidney problems; people with existing kidney disease should not use creatine. The most commonly reported side effects of creatine are diarrhea and muscle cramping, which seem more likely to occur with higher levels of supplementation.
Final protein pointers
Be sure you eat a good-quality, well-balanced diet, because without this foundation whey and creatine supplements won't do any good. Nutrients don't work well in isolation; aim to create a nutrient network in your body.