Vitamin D3
Mainly works when levels low: depression, ADHD, autism, sleep quality, negative symptoms of schizophrenia.
Coenzyme q10
For bipolar and unipolar depression [2], ADHD [3], autism [2], neurodevelopmental disorders [2], and energy in elderly.
SAMe
For depression, improves liver health, osteoarthritis, but l-methylfolate has a similar mechanism and better evidence.
L-methylfolate
[Deplin] Medium effect in depression augmentation [1], may help bipolar depression as well.
Creatine
Augments SSRIs in women only [3]. Improves memory, especially in older adults [2]. Long-COVID [3].