P-coumaric acid is an antioxidant found in peanut butter that could influence mood-regulating neurotransmitters in your brain. In fact, per a 2014 study published in Phytotherapy Research, oral administration of p-coumaric acid to mice seemed to have similar effects to that of oral diazepam, an FDA-approved medication for the management of anxiety disorders. It is thought that p-coumaric acid could have an unexpected effect on the gamma-aminobutyric acid (GABA) receptor in your brain — the part of your brain involved in calming your nervous system. 

In addition to p-coumaric acid, peanut butter contains beta-sitosterol (SIT), a plant chemical (phytosterol) that’s been known to reduce anxiety levels. In a 2021 study published in Cell Reports Medicine done on mice, beta-sitosterol was shown to reduce the effects of restraint-related stress and contextual fear memory. Additionally, phytosterols have also been linked with reducing the intestinal absorption of cholesterol,  promoting heart health, and protection against cancer. 

Another ingredient in peanut butter that could influence your stress levels is tryptophan. Recall how tryptophan-rich turkey dinners put you in such a relaxed and sleepy mood? Peanut butter could have the same merits. Your body needs tryptophan to make the mood-boosting hormone serotonin. Does this mean you should be turning to peanut butter whenever you feel stressed?