Taking Stacker diet pills (or any weight-loss pills) can come with a range of potential side effects.
1. Caffeine Toxicity
Because of their high caffeine content, herbal diet pills like Stacker 2 and 3 may cause nervousness, shaking, headaches, and dizziness.
Too much caffeine can also sometimes lead to caffeine toxicity, with symptoms like restlessness, anxiety, arrhythmias, nausea, vomiting, and electrolyte imbalance.
It’s hard to determine just how much caffeine is in each Stacker product because the amount often isn’t clearly listed on the label. But most contain somewhere in the neighborhood of 200 to 400 mg (milligrams) of caffeine, which is the equivalent of about two to five 8-ounce cups of coffee. This is generally considered a safe amount for healthy adults.
That amount may not bother everyone, but it can have negative side effects for those who are more sensitive to caffeine — and it may be too much if you’re getting additional caffeine from coffee, tea, soda, or other sources of caffeine. Pregnant people, children, and people with a chronic health condition should check with their doctor for advice on how much caffeine they can consume safely.
2. Digestive Issues
Prescription and over-the-counter weight-loss supplements can also cause digestive issues like constipation and diarrhea.
Chitosan can cause constipation, gas, and abdominal cramping when taken in large amounts. You should also not take chitosan if you’re allergic to shellfish.
3. Drug Interactions
Lastly, the herbs in Stacker diet pills may negatively interact with any prescription or over-the-counter medications you’re taking. For example, white willow bark is a known blood thinner, which could be unsafe for people on blood thinner medications or those dealing with heart issues.