I would report two experiences with substances derived from the Periwinkle flower:
1.) 1 oz. (1/2 bottle) of extract (contained ethyl (drinkable) alcohol) when I had ingested LSD (2 doses of blotter acid, probably about 170 micrograms - this was from a sheet I had ingested, prior, so felt fairly sure of its standard dose).
2.) Vinpocetine (this is the name of the standardized periwinkle flower-derived substance, which is the more powerful form, as compared to vincamine) from 'Nature Made,' in 5 mg. tablets.
When I was already on LSD for some hours and then, on an empty stomach, ingested the periwinkle flower in extract form, the first time, the periwinkle flower extract re-invigorated the introspective aspect of my LSD experience. An overwhelming feeling of being clearly in focus (on priorities, on whatever it was I was thinking about at any one time) came over me in just minutes after I consumed an ounce of the extract.
On another occasion, when not under the influence of any other substance, I took the other 1 oz. of the extract. I did not have the same feeling of clear focus.
I decided that the LSD must have potentiated the effect of the periwinkle extract.
Ten years later, in 2002, I noticed in a retail sun-dried/drug store, that vinpocetine was sold over-the-counter, and sitting on a shelf next to other supplements.
For most of 10 days, I took up to 20 mg. in a day of vinpocetine. While I did not find that the effects were specifically evocative of introspection, the substance did provide what felt like an increase in mental energy or alertness.
I did not experience any effects on my body, whatsoever, none of the heart palpitations that others have reported.
I only took the vinpocetine during the day, so I do not know if it would have had enough stimulating property to have disturbed sleep.
I would certainly take vinpocetine, again, were it not for the price/benefit ratio.
