Over-the-counter diet pills are rarely a good idea. U.S. law does not require them to be proven safe and effective prior to sale -- although many are harmless enough when used as directed, they rarely result in any meaningful weight loss. ViSalus Science's Vi-Slim is particularly worrisome because the ingredients are partially hidden behind a "proprietary formula," which means that although the individual components are listed, there's no way to know how much of each you're getting. Each ingredient carries its own list of possible side effects, and two of the ingredients are virtually unexplored.
The major problem with Vi-Slim is the stimulant content. All but two of the ingredients are considered stimulants, so those who are caffeine-sensitive should steer clear. Even if you tolerate normal amounts of caffeine without any problems, the total stimulant dose in each dose of Vi-Slim is unknown. You may experience nervousness, jitters, nausea, vomiting, diarrhea and headache. Severe cases can include irregular heartbeat and liver damage. If you decide to use Vi-Slim, tell your doctor first, and do not to use any other form of caffeine at the same time.
Various ingredients in Vi-Slim are known to react negatively with certain medical conditions. The green tea extract can worsen anxiety, anemia, bleeding disorders, high blood pressure, osteoporosis, heart conditions and diabetes. Forskolin can exacerbate low blood pressure and rapid heartbeat, and can increase headache occurrences. Yerba mate can complicate heart conditions, anxiety and high blood pressure, and also increases your risk of certain cancers. None of the ingredients are safe for women who are pregnant or nursing.
Each Vi-Slim ingredient also reacts to other medications and supplements. Yerba mate interacts with chemotherapy drugs, and Forskolin interferes with medications for high blood pressure and anticoagulants. Green tea extract should not be used with any stimulant medication, and can interact badly with birth control pills, certain antibiotics, cimetidine, adenosine, fluvoxamine, lithium, asthma medications, anticoagulants, blood thinners, theophylline, fluconazole, diabetes drugs, antifungal medications, as well as supplements like bitter orange and creatine. It is vitally important that you consult your doctor before taking Vi-Slim if you are taking any medication.
Possibly the most concerning thing about Vi-Slim is that two of its ingredients, theobroma and evodiamine, are almost completely unstudied. There is no published research available about either of these substances as used for weight loss, and there is no established dosing guideline or recorded side effects. The scant evidence that exists does not report side effects during study, but there is no way to compare the dose used in the studies to the dose in Vi-Slim, because Vi-Slim doesn't list the amount of either substance. This also means that potential interactions with medications or other supplements are unknown. The U.S. Food and Drug Administration does not require supplement makers to prove that their products or safe or effective before sale, so you essentially must use Vi-Slim at your own risk.