Three updates this week, all have neurological implications, but are seemingly unrelated to each other.
Piracetam could be seen as our major update due to its popularity, but its status as a cognitive enhancer (nootropic) is not really too sound. It has a few mechanisms, the most interesting would be being able to preserve membrane fluidity (cell membranes should be fluid, and rigid cell membranes exist in many disease states and hinder signaling from one cell to another) and it also appears to have effects on neurons; the latter being positive AMPA modulation (sounds sexy, but is basically 'controlling excitation through a neuron to a degree') and selective CaV2.2 ion current inhibition (same thing as before; sounds sexy but reduces excitation a bit).
The former appears to be more relevant. The observations with Piracetam is that it provides non-specific cognitive improvement in the cognitively impaired with minimal efficacy in healthy persons; correlating well with membrane fluidity. The effects on AMPA receptors and CAV2.2 channels are unilateral and probably related to cognitive boosting in healthy persons.
Unfortunately, they are probably very weak as cognitive boosting in healthy people from Piracetam is weak at best and unsupported otherwise. It has a large body of evidence for restoring a degree of cognition to the impaired, not for being a brain booster.
Further tied in with increase membrane fluidity are the effects of Piracetam on blood cells. It appears to be as effective as Aspirin in preventing death following stroke (when used as daily prophylaxis over 2 years), which may be related to the interactions with membrane fluidity.
Overall, Piracetam is basically a health and longevity compound and a weak cognitive enhancer per se. Choline is not needed for its cognitive boosting effects, although one rat study suggests that they may be synergistic (in the grand scheme of things, that is poor evidence). Piracetam is non-toxic and remarkably effective for Breath Holding Spells in infants.
S-Adenosyl Methionine (SAMe) is a methyl-donating intermediate which appears to follow some nutrient-like compound motifs in the body. Although it takes a month or two to reach maximum effectiveness (for unknown reasons), it appears to be as effective as an older class of anti-depressants (the tricyclic antidepressants) and modern anti-inflammatory pharmaceuticals for depression and osteoarthritis, respectively. It should theoretically be a nice addition to any health stack, but it could potentially just be useless in otherwise healthy persons with sufficient SAMe levels in serum; with the price of SAMe, this is a critical factor (it is not a cheap compound). Finally, it is the second compound in our database (creatine being the first) to augment the efficacy of SSRIs in anti-depression; SAMe tends to play nice with pharmaceuticals, which is surprisingly rare in a world of supplements where they tend to be contraindicted due to enzyme inhibition.
Vitex Agnus Castus is an herb with dopaminergic (acting like dopamine) and opioidergic (acting like opioids) mechanisms in the body, and due to these it can reduce prolactin levels in both genders and appears to be an effective anti-PMS supplement. Despite placebo being very active in PMS studies, VAC routinely outperforms placebo on global rating scales (ie. does not show preference for any specific subset of PMS symptoms, but tends to benefit all). PMS is the most well studied and practical usage of VAC, although theoretically it should be beneficial for after a testosterone boosting cycle when high prolactin levels are a concern.