95% of all supplements you find in magazines and bodybuilding stores are a not as good as the producers say they are. Do not believe any testimonials that are posted by that company. The best way to find if a product is good is to ask around on the message boards here at Bodybuilding.com.
Good
Many of the supplements that fit into this category make up the mainstay of many bodybuilders' diet/food regimes. All of them serve some purpose well, and for some the cost is well justified.
Meal Replacement Powder (MRP)
Which is to be thought of as healthy fast food, and nothing more. In your attempts to increase your daily caloric intake, MRPs provide a fast and convenient source of quality protein, carbohydrates and (sometimes) EFAs. Given the cost in buying quality "real" food, MRPs are often a good choice. Typically, a MRP is 260 Calories and has a macronutrient ratio of PCF 37g/24g/0-2g.
Protein Powder
During dieting, it is often a good idea to increase total protein consumption, but with a concurrent reduction in carbohydrate and fats. This can be done easily with a protein powder, which generally has a PCF of 17-40g/0-3g/0-1g. There are varying qualities of whey protein, the best of which may be Next Nutrition's Ultimate Designer Whey Protein. But, so long as you have filtered, ion-exchanged whey you should be fine. Some good protein powders would include Simply Whey (EAS), Vyo-Pro (AST-SPORTS), VP2 (AST-SPORTS), Designer Protein.
Creatine Monohydrate
One of the few natural, legitimate supplements that generally works for most trainers. Creatine monohydrate, when loaded for 5-7 days at 30-20g/day and maintained at 3-5g/day, helps increase your lifting endurance slightly. You may find that you are able to lift the same weight for an extra few reps, or possibly even more weight. In addition to the strength benefits, most people generally gain 5-15lbs (water retained weight) and will achieve much fuller pumps from the gym. Very safe. It has been tested for years on a vast number of athletes, and is the basis for countless non- partial studies.
The primary drawback is the relatively high cost to maintain. It has been indicated that high maintenance dosing (15g/d) may have other systemic benefits. As a cost saving, the loading period can be skipped, although it may take a month to reach saturated muscle creatine levels. For best absorption, take your dose (no more than 5g at a time) with a high glycemic index drink (eg. grape juice) and no proteins or fats. This will cause a delayed increase in blood-glucose levels which will trigger a period of high insulin. This insulin "spike" will allow the CM to be absorbed considerably better than if it were taken alone, or with a meal.
Vitamins
It is pretty well accepted that supplementation with 500-1000mg Vitamin C/day is good. Vitamin A & E are also worthwhile, but a multivitamin may do as a substitute.
Workout Drinks
Usually derived from the herb Ephedra (a precursor to Ephedrine), Ma Huang is a reasonable CNS stimulant. Typically used for fat loss (as the ephedrine component in ECA), or as a workout kick. Products such as Ultimate Orange include both Ma Huang, Guarana and Kola Nut along with a good carbohydrate source, resulting in an excellent kick-start to your heavy workouts. Stimulants must be used infrequently, as otherwise your receptors will gradually downgrade and the same dosing will no longer be as effective. Take breaks occasionally. These drinks work well for many, and can have you bouncing off the walls in the gym within 45 minutes.
DHEA
If you're a male over the age of 35, your natural DHEA production has probably slowed to the point where supplementation may be beneficial. DHEA is weakly converted to testosterone in the body, and is known for a moderately high side-effect to gain ratio, but being legal, it's fairly popular.
Supermarket Foods
Quality protein sources include tuna (packed in water), chicken breasts, salmon, low-fat yogurt, skim milk powder, chocolate milk. In addition, look out for Flaxseed Oil or other good sources for Omega 3 & Omega 6 fatty acids.
Okay
This section includes supplements that potentially serve a particular purpose, or its efficacy has not been established well.
Weight Gainers
If you are an ectomorph, or have significant trouble gaining weight, then the game becomes a matter of eating more. Many of us need to eat a good 4000 calories/day to gain weight. It is best that most of these calories are in the form of regular, cheap food. But it is not always possible to get this amount of food. In such circumstances, it may be worthwhile to check out a weight gainer (look for ones that have at most 1200 calories). These are generally mixes that contain maltodextrin (or some other sugar) along with a blend of proteins (usually some whey, caseinates, egg whites, etc.).
The quality of protein in these mixes doesn't compare to that found in protein powders, but at least you are getting a moderate quality food. The higher the calorie content, the more sugar and fat they generally add. One must be careful, though, as weight gainers will put on significant fat mass if your metabolism is not geared for high-calorie needs. A better alternative is to take a MRP and add milk (to get ~350-400 calories) or half the serving size for a weight gainer (~400-600 calories).
HMB
Beneath all of the magazine hype, one will discover that there is only one study that shows any weight gain benefits with HMB supplementation, and this study is subject to considerable scrutiny given the proponents of the study (Nissen, Connelly, etc.). It seems, by anecdotes from various people that HMB does not work at all, much less worth its high cost.
Connective Tissue Healers
There are a few products available on the market that claim to speed recovery of tendon and ligament injuries. The most successful of these are: Glucosamine Sulfate (1.5-2 g/d), shark cartilage and gelatin (0.5-1 oz/d).
Amino Acids
Although included in the "Bad" section below, some may carry slight benefits, including L-Glutamine and Acetyl L-Carnitine. However, the costs probably outweigh the potential benefits.
Vanadyl Sulphate
Vanadyl sulphate is touted as an insulin-mimicking agent. This would be very useful for the average bodybuilder's diet, as it enables certain meals to be absorbed better than usual. In particular, it would be a good idea to take the VS caps with a meal that is high in carbohydrate and protein. The carbohydrates are important, as they prevent possible hypoglycemia. The increased insulin levels would then allow the glycogen stores to be replenished effectively, in addition to increased protein absorption.
However, it has not been shown that VS actually increases absorption into muscle stores. Other potential drawbacks include the heavy metal buildup which may result in toxicity after continued use.
Bad
These supplements are generally a waste of money in almost every case. Most of them have no research to show any demonstrated benefit to the average consumer, with the recommended dosing.
Boron
A good example of where studies were used to mislead your average muscle magazine consumer. It was shown in one study that the supplementation of boron increased testosterone levels by 600%. Sounds great. They failed to mention that this was for post-menopausal women with boron deficiencies (if I recall correctly). For the average young male, boron does nothing.
Plant Sterols
I have yet to see any evidence that plant sterols provide some significant benefit for humans. It has been claimed that these sterols may help increase one's nitrogen balance, but I located any relevant studies. Unfortunately, the potential positive benefits of plant sterols is destroyed by the abundant advertising with vast claims or references to "steroid alternatives".
Pyruvate
Although there appears to be some benefit in *high* dose supplementation of Pyruvate for weight loss, we are talking in the order of 30g/day. The Pyruvate distributors would like you to believe that you will get the same fat-burning benefits at the serving dose of 5g. It has yet to be proven. Most of the pyruvate is converted to lactic acid and leaves the Krebs cycle. For significant fat-burning effects (not great, at any rate), maintenance would cost on the order of $30/day (for study-based dosing). MLM scam.
Amino Acids
Amino acids are absolutely essential for protein synthesis, but any whey protein will give you adequate coverage of ALL 10 essential amino acids. Most meats and fish will also contain a full gamut. Vegetarian diets are often lacking one or two essential AAs, and so either a careful selection of vegetarian foods should be made, or else supplementation of amino acids should be done. There may be some value in supplementing particular amino acids for other reasons, but the cost probably outweighs the potential benefits.