For the bodybuilder, the most appealing of the current crop of diet drugs are the amphetamine derivatives. They can be successfully used for a short period of time to burn significant amounts of bodyfat, particularly the stubborn bodyfat that is highly resistant to dieting and will not seem to disappear even towards the end of a cutting cycle. The stimulating properties of these drugs can dramatically enhance the fat burning effects of a ketogenic diet. Here are the stimulating diet drugs listed from weakest to strongest. Their differences in pharmacology are small, but the effects they produce on the individual can vary widely. Tenuate: (diethylpropion hydrochloride USP) - the mildest. Phentermines: (brands: Adipex; Fastin, Ionamine) Bontril: (Phendimetrazine tartrate) Didrex: the brand name for Benzphetamine - the strongest. All the amphetamine based diet drugs have both the good and bad side effects of amphetamine - but to a lesser degree. What dieters like about these drugs is that when on them, you feel very well stimulated. You feel euphoric, have boundless energy, and are without fatigue. But the downside is that unless kept in check, they can be habit forming, and when you stop using them - as you must from time to time - you crash and feel highly fatigued. Tenuate, the mildest of the stimulants, is basically one notch higher than caffeine in terms of stimulation. The best thing about Tenuate is that the lower dose tabs can be used during problem hours of the day to curb the appetite. Most athletes have specific times throughout the day when they are particularly susceptible to breaking their diets. At these times of craving, Tenuate can be of aid. The main downside is that Tenuate begins to lose its simulative effect at around week three. In terms of effectiveness and simulative properties, the next step up from Tenuate are the Phentermines. The Phentermines come in two flavors: Phentermine hydrochloride and Phentermine resin. Phentermine hydrochloride goes by the brand names Adipex, Fastin, and just plain Phentermine. Phentermine resin goes by the name Ionamine. Adipex and Fastin are 30mg tablets that exert their effect for 10 to 12 hours. Ionamine is believed to have a longer duration, but a milder effect. Ionamine is usually more expensive than Phentermine, and in the real world, the differences between the two are largely subjective. The Phentermines can promote pronounced fat loss and are highly effective. Bontril-SR is the brand name for Phendimetrazine tartrate. It is a stimulant that is supposedly stronger than Phentermine. Based on discussions I have had with consultation clients, many cannot differentiate between the two in terms of effects and effectiveness. They instead choose one or the other based on price and availability. Unfortunately, because there is a high cross-tolerance between Phentermine and Bontril, one cannot simply step up from Phentermine to Bontril when Phentermine loses its effectiveness. Didrex, is the brand name for Benzphetamine and it is the closest of all the diet drugs currently available to amphetamine. Benzphetamine is metabolized into methamphetamine and amphetamine, which may explain its reputation for having a greater abuse potential than Phentermine. Additionally, it has the drawback of making you test positive for amphetamine and methamphetamine in urine drug screens. On the plus side, it is definitely a step up in effectiveness from the Phentermine style diet drugs and affords the dieter who has gotten all of the possible benefits from the milder diet drugs a place to go for further weight loss.