Creatine is one of the few supplements that actually produces rapid results. When used properly you can expect a 5 to 7 lb weight increase within the 1st four to five weeks of using this product. Keep in mind however that this weight increase is not due to the addition of muscle but forced hydration of the muscle cells. The end result is an almost immediate increase in size with a corresponding increase in strength. These results will be maintained only as long as you continue to use the product. I have never experienced side effects from using Creatine however others that I know have experienced stomach problems.
 

Bottom line, if you are on a mass gaining program, definitely include Creatine in your supplement program. If your goal is to cut weight and go for maximum definition I would suggest Glutamine as an alternative.

What is Creatine?
 

Creatine is an essential naturally occurring nutrient found in the human body and the bodies of most vertebrates. Creatine is a major form of energy storage used to power muscle contractions, particularly in movements that are quick and explosive in nature. This powerful ergogenic aid is produced through both endogenous (internal synthesis), and exogenous (dietary intake) sources. The biosynthesis of creatine is known to take place in the liver by combining parts of three amino acids arginine, glycine, and methioine. Dietary sources come primarily from the intake of meat, fish, and other animal products.1
 

How Does Creatine Supplementation Benefit Humans?
 

Most studies which have investigated the ergogenic value of short-term and/or long-term creatine supplementation have reported significant increases in strength/power, sprint performance, lean muscle mass, and/or work performed during multiple sets of maximal effort muscle contractions.2 The improvement in exercise capacity and increase in muscle mass are attributed to increases in the creatine content of muscle and creatine phosphate levels within muscle cells. Creatine supplementation through short-term "loading" has been reported to increase muscle total creatine content by 10 to 25 percent, and creatine phosphate content by 10 to 40 percent.3 During intense exercise the muscles are quickly depleted of their creatine supply. Therefore, the more creatine stored in the muscles the more energy is available to activate the muscle tissue.
 

What's the Best Way to Use Creatine?
 

Creatine in the form of creatine monohydrate is widely used by athletes all around the world. Creatine monohydrate is chemically identical to creatine except for the addition of a single water molecule. Pure creatine monohydrate is a white odorless crystalline powder that is virtually tasteless, and is easily soluble in water. Most experts recommend that an initial high dose (loading dose) of creatine be taken the first week of supplementation. Creatine loading is a method for maximizing the amount of creatine stored in muscles. Studies have shown the greatest amount of creatine uptake occurs during the first 3 to 5 days of ingesting loading doses.4 It is also suggested that creatine monohydrate be ingested with glucose or fruit juice. Recent research has shown that taking creatine with simple carbohydrates can facilitate the transport of creatine into muscle cells reducing the variation between individuals.5,6 Muscles have an upper limit of creatine uptake and creatine storage, therefore, elevated levels of muscle total creatine content and creatine phosphate content can be maintained thereafter by a maintenance dosage.
 

What's the Proper Dosage of Creatine?
 

Generally the dosage of creatine should be as high as necessary, but as low as possible to be effective. Many manufacturers use total body weight or lean muscle mass as a measure for supplementing creatine. However, many scientists consider transport capacity to be the primary factor in saturating muscle tissue. In this regard, creatine supplementation appears to be less ergogenic when supplementation regimens are less than 20 grams/day for 5 days.7 Furthermore, ingesting more than 20 grams of creatine per day appears to offer no additional performance benefits. Consequently, many researchers recommend ingesting 20 grams of creatine monohydrate for 5 to 7 days in four 5-gram doses each day, and to ingest each dose with a simple sugar carbohydrate solution (20 to 95 grams of glucose in 250 milliliters of water). Thereafter, elevated levels of muscle total creatine content and creatine phosphate content can be maintained by ingesting 2 to 5 grams/day with the same simple sugar carbohydrate solution.4
 

What are the Side Effects of Creatine Supplementation?
 

The only side effect reported from clinical studies investigating creatine dosages of 1.5 to 25 grams/day for 3 to 365 days in trained, and untrained subjects has been weight gain.8 There have been a number of anecdotal reports claiming that creatine supplementation may cause an upset stomach, diarrhea, promote muscle strains/pulls, or contribute to muscle cramps. However, no study has determined that creatine supplementation causes cramping, dehydration, changes in electrolyte concentrations, or increases susceptibility to muscle strains/pulls, even though some of these studies have evaluated highly trained athletes undergoing intense training in hot/humid environments.9,10 If you are using a creatine supplement it is suggested that you consume ample amounts of water (at least 3 liters of water/day) to avoid dehydration, and do not take more than 5 grams of creatine in a single dosage.