Weight loss pills that are available for sale online have different mechanisms of action. They work on the brain to suppress appetite or increase metabolism while others work locally in the body to increase metabolism of fat. Regardless of the mechanism of action, they have been shown to give better results when combined with a low calorie diet as well as high intensity exercises.
Lorcarserin is a centrally acting appetite suppressant. It acts by binding to Serotonin receptors in the brain. Once this binding occurs, there is increased production of Proopiomelanocortin, POMC. This then leads to suppression of the appetite center and gives a feeling of satiety. This is important in people who are trying to lose weight as there is reduced calorie intake. It is marketed by the trade name Belviq.
Benzphetamine is known commonly by its trade name Didrex. It is an amphetamine prodrug. Once ingested, it breaks down to form amphetamine and methamphetamine which have a sympathomimetic effect. It works mainly through the suppression of appetite but has been shown to have a mild action in increasing the basal metabolic rate.
Phendimetrazine is also very active in its ability to suppress appetite. It is converted into an active compound once in the body and increases the levels of Dopamine as well as Norepinephrine through the stimulation of the Norepinephrine Dopamine Releasing Agent. It is available in the form of slow release capsules as well as fast acting ones.
Phentermine is also a sympathomimetic weight loss pill that works by appetite suppression in the brain as well as increasing thermogenesis and the rate of metabolism in the body. This drug increases the use of stored fats as a source of energy. It therefore leads to better metabolism as well as faster loss of weight like on anabolic steroid pills.
Orlistat marketed as Xenical is a lipase inhibitor and is available for sale in pharmacies but with a prescription. In some countries it is available over the counter under the trade name Alli. It works by inhibiting absorption of digested fats. It is slow acting in terms of weight loss because it works more to prevent new weight gain. However trials showed it led to slow weight loss in its users.
Almost all weight loss pills are associated with the possibility of abuse. This is because they are psychoactive. This therefore necessitates their short term use. They should be combined with a low calorie diet and physical exercises to be more beneficial.