Reported side effects of using Formula 303 include drowsiness and gastric upsets, explains Westminster Accident and Injury Center. Formula 303 is made from a herb known as valerian; side effects of using the plant include insomnia, excitability and headaches, notes WebMD.
Formula 303 is a typically used to relieve stress, muscle spasms and tension, explains Westminster Accident and Injury Center. The product is generally considered safe and non-addictive and has very few reported side effects. Reported side effects include drowsiness, a problem typically relieved through dosage reduction, and gastric upsets, a problem usually resolved by taking Formula 303 with food.
Valerian, one of the main ingredients in Formula 303, has proven effective against insomnia, and insufficient evidence indicates that it can be used to treat anxiety, depression, stress and dysmenorrhea, explains WebMD. Some of the reported side effects of valerian include lethargy in the morning, excitability, uneasiness and insomnia. The herb should be avoided by pregnant and lactating women.
Other primary ingredients used in the making of Formula 303 are passion flower and magnesium carbonate, notes the Chiropractic Centers. Passion flower is effective against anxiety, nervous tension and hysteria while magnesium carbonate is a good source of magnesium, a mineral that helps prevent excitability.