I would like to comment on that Sphingolin again....

Here is why I don't like the thought of this supplement:

http://neurotalk.psychcentral.com/post1144611-3.html

The Sphingolin seems iffy to me and too risky. The bovine sources are often not identifiable as having Mad Cow. I believe a young cow was recently found with the disease. The Prions are difficult to find, and impossible to kill (instruments used on patients for open head surgeries, are thrown away... because they cannot be sterilized). I myself would never take any bovine or other animal organ derived supplement.

I am not aware of any testing of bovine nervous tissue, for prions. I don't believe they exist. They elude sterilization techniques that are used on surgical instruments, and so those used by neurosurgery are discarded and charged to the patients.
Every once in a while you can see news articles of nvCJD passed to patients by wrongful reuse of instruments. nvCJD is the human name for prion disease.