We have no idea how this supplement is still on the market.
Prevagen is perhaps one of the biggest shams on the supplement market. The FDA has gone after them for false advertising , they've been sued for their lack of evidence  and their self funded study wasn't even a fraction as effective as they claimed if you actually look at the full results. 
The worst thing about this, is that there are numerous effective ways to actually boost your cognitive function. Just Prevagen isn't one of them, at least it wont work any better than a vitamin D pill, which is the main ingredient of the pill.
Prevagen does include one more ingredient, Apoaequorin, this is the root of all the controversy as it's functionally snake oil. Prevagen is so bad in terms of it's false claims, it could well be the reason for further regulation into the supplement industry.
Before you write off the entire supplements industry we should mention there are some supplements that do actually help brain function and it's not all a complete disaster. Of the couple of compounds and herbal extracts that could help boost cognitive function, help with memory problems and mood regulation, the most promising are citicoline and phosphatidylserine which have actually been backed in multiple clinical trials. You can learn more about which over the counter supplements actually improve brain function here.
Some Of The Most Commonly Asked Questions About Prevagen
As you'd probably expect the customer review of Prevagen aren't exactly positive. With most people saying it had little effect and those that did report it having any positive results were probably vitamin d deficient. The reality is that most Americans would benefit from supplementing vitamin d especially in winter with almost half of the population being deficient.  As a result some people will have actually seen statistically significant improvement in their overall brain health. As vitamin D at least is proven to improve brain function.  The key difference is a bottle of vitamin d pills will set you back a couple of dollars not 30-40.
We've already talked about vitamin D3, which does have some benefits, so what about Apoaequorin. The controversial ingredient. Let's start with the side effects of apoaequorin, because it's not off to a great start, when taken at levels of 10mg/day or above (the dosage in Prevagen) it can cause:
The later obviously being the most concerning, the reality is that prevagen side effects can be quite serious.
In terms of what it actually does, very little, in theory it was thought that it could reduce calcium build up in the brain, but the reality is that there isn't any reliable evidence to suggest that it does this and it seems that it doesn't pass from oral ingestion effectively even if it could work . T
aking prevagen will do no more than a vitamin d pill, which could have some positive impacts and would improve memory, give clearer thinking a sharper mind etc. But, once again, just take a vitamin pill. Don't waste your money on Prevagen, to be perfectly honest, we're not entirely sure how this farce of a supplement is still allowed to be on the market.
Prevagen made a lot of wildly deceptive claims, and is nothing short of a predatory company. There are some nootropic supplements that can help with brain health, but companies like Prevagen only serve to give the entire supplements industry a bad name. The fact that major retailers still stock it, is rediculous. Not only does it not work, but there's a good chance that it's dangerous. It's rare that we have to say this, but you'd be better off taking nothing than taking Prevagen. Usually supplements usually just overpromise, few are actually dangerous.
We have spent a lot of time reviewing supplements that provide reliable evidence and don't make false claims. If you're looking for a dietary supplement to support healthy brain function, then we recommend having a look at our list of best nootropic supplements .
1 - https://www.ftc.gov/system/files/documents/cases/quincy_bioscience_holding_co_ftc_amended_reply_7-17-18.pdf
2 - https://www.reuters.com/article/quincybioscience-ftc-memorypills-idUSL1N1EZ13E
3 - https://www.pharmacytoday.org/article/S1042-0991(15)30157-2/fulltext
4 - https://pubmed.ncbi.nlm.nih.gov/21310306/
5 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6132681/
6 - https://www.ncbi.nlm.nih.gov/books/NBK552157/