Supplements with evidence for treating ADHD:
Ginkgo Biloba
Korean Red Ginseng (/Manchurian Ginseng in UK)
Passion Flower
Phosphatidylserine
Fish Oil
Borage Oil
Acetyl Carnitine
Zinc
Magnesium
Scutellaria Baicalensis - (watch out guys, it's estrogenic)
No actual evidence but may be promising:
Chaenomeles Speciosa - selective DRI
Akebia Trifoliata - SRI & NRI & DRI
On a side note, I was quite disappointed to see that both Ritalin and Amphetamine have been shown to reduce testosterone. I sure hope this is not found at clinically relevant dosages.