Natural appetite suppressants are safe and do not have harmful side effects compared to prescription medications. As much as the natural appetite suppressants are safe, some people may experience mild side effects such as nausea, dizziness, and upset stomach. Most appetite suppressants have caffeine as an ingredient. A safe dose for caffeine is 100mg per day, and more may cause paranoia and jitters. If you take the dosage as recommended, this will not be a problem. If you are taking other medications with appetite suppressants, it’s imperative to talk to your doctor to know the interaction of the drugs.