Without going into all the details here is a summary of some of the most common supplements. The key angle is that you want to look at these as “ergogenic” aids… those that enhance performance… in our case – running.
Caffeine – for events 800-3000 it may improve performance; 200 mg 1 hour before the race. Coffee itself has ingredients that block the absorption of some of caffeine in the drink. NoDoz is a substitute. It does not help races longer than 300 meters. Significantly higher dosages impede performance. 1200 mg is prohibited level for USATF/NCAA, etc. If you are a regular coffee drinker (or other caffeinated beverage) the affect on you is reduced. On the other hand, if you are unaccustomed to any caffeine you may suffer unpleasant side effects from nervousness, jitteryness, upset stomach to diarrhea.
Creatine is legal and has been shown to help with high intensity workouts. It is beneficial to power oriented activities. Therefore, it does not help distance runners. Creatine phosphate is an energy store for immediate use (i.e. jumping from in front of moving bus). It is also a buffer for higher Ph in muscles. It does however lead to water storage and weight gain. 6k runners gained 1% in weight and lost 1% in time. It is expensive. The target amount is 3 Gms/day. There are no side effects to speak of.
Protein whey and protein powders do not improve performance, muscle building or repair. Carbs are much better. Accelerade commercials are inaccurate. The protein + carbohydrate mixture does not improve performance by 29% as advertised when compared with identical caloric straight carbohydrate drinks. Their comparison is against a lower calorie drink, therefore, by definition it would have more energy… it has more calories. But, be clear, it is not the protein that is doing it, just the calories. Since carbs are used for energy more readily than protein, stick with the carb sports drinks.
Antioxidants (C & E) have some affect on immune system and recovery. But, these are not truly ergogenic. The same can be said for St. John’s Wort for relaxation effect, and echinacea on your immune system.
Sodium bicarbonate has been shown to buffer the acidity in muscles and therefore has some impact on performance. However, the side effects are frequent with GI problems (gas and diarrhea).