The FDA recommends that healthy adults' maximum caffeine intake is 400 milligrams.
The FDA has stated that for healthy persons, 400 mg per day—roughly four or five cups of coffee—is a level that is not typically linked to harmful, adverse effects. However, there is a huge range in how quickly people metabolize caffeine as well as in how sensitive they are to its effects (break it down).
Anxiety, headaches, insomnia, upset stomach, and other side effects might result from consuming too much coffee. As a result, a business may decide on its own that using caffeine constitutes GRAS without the FDA's approval. The FDA has only approved the use of caffeine in cola-style drinks at a tolerance level of 0.02 percent.