Thoughts on the Vinpocetine Safety Controversy

There’s been a controversy around the safety and efficacy of Vinpocetine. This controversy seems to have originated at Longecity with this thread entitled “Vinpocetine – Ditch It”: http://www.longecity.org/forum/topic/23457-vinpocetine-ditch-it/

 

Wikipedia, however, on their Vinpocetine article states that “Vinpocetine is generally tolerated well and without many cases of adverse reaction reported.” – http://en.wikipedia.org/wiki/Vinpocetine

 

The debate has raged on reddit as well, with people taking different sides of the argument. Some take Longecity’s side, and others take the stance that it’s generally safe. I intend to look at both sides of the argument in this article.

 

Longecity’s Studies

Longecity’s studies were not immediately found upon pubmed, but the texts of the studies were included in the post. These studies stated the following:

  1. The effect of Vinpocetine on the Dopaminergic system has been scarcely evaluated

  2. vinpocetine at increasing concentrations progressively decreases internal DA and increases DOPAC release

  3. Vinpocetine *MAY* act in a reserpine-like fashion

  4. Vinpocetine inhibits NMDA channels similarly to Zn2+ in Xenopus oocytes

  5. Vinpocetine is an AMPA antagonist of some specificity

 

Original Poster’s Interpretation

The original poster, after reading these studies came to the following conclusion: “Then I noticed through researching studies that vinpocetine has a negative impact on the NMDA receptors and the AMPA receptors.  These are two very important receptor systems that substances claimed of being nootropics should elicit a positive affect on or no affect at all.  Here are two studies which show vinpocetine have a negative affect on them, I THINK!“

 

My Reading

Now, I’m not one of the scientists that did these studies, so I can’t claim to know exactly what the experimenters saw or what they were thinking. I’m also not attempting to create to ad-hominem attacks against the people who made the post. I’m attempting to clarify these points.

 

  1. Vinpocetine’s effect on dopamine:

    1. The study was attempting to determine the method in which Vinpocetine affects dopamine. The effects, in the study, appeared to be similar to the drug Reserpine, although not as strong.

    2. The “negative effects” referenced throughout the rest of the first article are actually about Reserpine, and not Vinpocetine

    3. These effects reversed quickly after Reserpine administration was ceased

    4. This study was not performed in humans, nor does a decrease in internal DA and increases of DOPAC release necessarily reflect a negative overall cognitive effect.

    5. Decreases in internal DA and increases of DOPAC release can be seen in other dopamine-related stimulants

    6. My Conclusion: Although this warrants further study, I don’t view this as conclusive evidence against taking Vinpocetine, especially when numerous clinical trials point to positive cognitive benefits even over an extended period of time.

  2. Vinpocetine’s effect on NMDA

    1. The study says that Vinpocetine’s effect as an NMDA antagonist is similar to elemental Zinc. Zinc’s effects on the NMDA system are generally weak.

    2. Zinc is a common additive in multivitamins

    3. Being an antagonist does not mean that there is neurotoxicity occuring, nor does it necessarily imply long-term harm.

    4. My Conclusion: This is not conclusive evidence that Vinpocetine has a net negative effect on NMDA receptors, or at least, is no more negative than your typical multivitamin.

  3. Vinpocetine’s effect on AMPA

    1. The study only said that Vinpocetine was an AMPA antagonist of some specificity

    2. Although a lot of nootropics such as Aniracetam are AMPA agonists, Vinpocetine appears to be a fairly weak AMPA antagonist.

    3. Being an AMPA antagonist is not necessarily a “bad” thing, nor is it evidence of any sort of neurotoxicity.

    4. My Conclusion: Vinpocetine’s actions at the AMPA channels is not necessarily negative or strong.

 

My Overall Conclusion:

The potential DA decrease and DOPAC increase could possibly indicate something negative, although the studies quoted are really referring to Reserpine and not Vinpocetine. Also, the levels returned to normal soon after ceasing Vinpocetine, indicating no long-term neurological damage. In terms of its effects on AMPA and NMDA, these are not necessarily indicative of neurotoxicity or long-term negative effects.

 

In the end, if Vinpocetine works for you, I suggest you continue using it. It is generally well-tolerated and its efficacy has been proven again and again in clinical trials. I still suggest you educate yourself on the issue and don’t take my word for it, but that’s my reading and opinion.

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