To date, most studies have been conducted using a daily dose of 1mg of food-derived spermidine, which is the amount present in Primeadine. The US FDA has not ruled on a safe upper limit for food-derived spermidine, but the European Union's European Food Safety Authority has deemed 6mg of supplemental food-derived spermidine to be the safe upper limit. Synthetic spermidine has not been tested for safety in humans.