Fish oil contains the omega-3 fatty acids DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), which have well-supported anti-inflammatory properties and can regulate neurotransmitter and immune function, and as a result, may improve ADHD.[1]
Ginkgo biloba increases blood flow in the human brain and the signaling of serotonin and norepinephrine in rats, which may contribute to its mild, positive effect on ADHD.[2][3]
Both L-carnitine and acetyl-L-carnitine are present in brain cells and play an important role in energy production — it’s possible that by increasing mitochondrial activity in neurons and promoting dopamine signaling, carnitine could improve symptoms of ADHD.[4]
Supplementing with phosphatidylserine (a phosphorus-containing lipid) seems to positively affect ADHD,[5] which is likely due to its important role in adjusting receptor, enzyme, and ion channel activity, and consequently, affecting the signaling of most neurotransmitters in the brain.