What Are the Side Effects of Prevagen?

The supplement industry, in general, is poorly regulated. This has resulted in the release of products with dubious levels of efficacy, not to mention questionable safety. The nootropics section of the industry is rife with such products.

According to Verified Market Research, the nootropics market was worth $2.42 billion in 2020 and could rise to $6.29 billion in 2028. Therefore, countless brands are jumping on the bandwagon, and it is already a case of ‘buyer beware.’

Prevagen is one of the most successful and controversial nootropics currently available. Created by Wisconsin-based Quincy Bioscience in 2007, an estimated three million people have used the supplement. To date, Prevagen reviews on Amazon.com and other sites are relatively positive. Quincy Bioscience also claims that there are no serious Prevagen side effects.

However, the brand has suffered enormous blows to its credibility in recent times. Issues with the FDA and lawsuits have tarnished its reputation. There are now grave concerns regarding the effectiveness of Prevagen, but is it safe to use? This article looks into the possible side effects of this supposed memory-improving supplement and analyzes whether it is worth taking.

What Is Prevagen?

Prevagen is a nootropic linked with improvements in memory. Its main ingredient is apoaequorin, a protein in Aequorea victoria, a jellyfish famed for glowing in the dark. It is a calcium-binding protein. This is important because there is research showing a link between calcium and brain health & memory. If there is a calcium imbalance in brain nerve cells (neurons), it may lead to premature aging and cell death.


Quincy Biosciences suggests that the apoaequorin in its product “uniquely supports brain function.”

The original version contains 10mg of apoaequorin, whereas the newer Extra Strength capsules contain 20mg of the protein each.

What else is in Prevagen?

There is one additional active ingredient; 50mcg (2000 IU) of vitamin D3 per capsule. There are 30-count and 60-count bottles of Regular Strength and Extra Strength Prevagen, along with a Professional Formula containing 40mg of apoaequorin.

Prevagen capsules contain the following additional ingredients in a vegetable capsule comprised of water and cellulose:

  • Microcrystalline cellulose
  • Maltodextrin
  • Salt
  • Soy peptones
  • Modified corn starch
  • Sugar
  • Casein peptones
  • Magnesium stearate
  • Lactose

Before discussing the possible Prevagen side effects, let’s discover why people use it and delve into the research.

What Is Prevagen Used for?

According to Quincy Bioscience, Prevagen is “clinically shown to help with mild memory loss associated with aging.” The brand also suggests the product supports:

  • Clearer thinking
  • A sharper mind
  • Healthy brain function

In general, the majority of people who use Prevagen do so to help improve their memory. Most users are approaching senior citizen status, although younger individuals sometimes try this product. Quincy Bioscience also points out that the product is intended for healthy people who do not have dementia.

The apparent effectiveness of Prevagen is based entirely on one study conducted by Quincy Bioscience. Known as the ‘Madison Memory Study,’ it involved 218 people from Madison, Wisconsin, aged between 40 and 91. They received either 10mg of apoaequorin or a matched placebo daily for 90 days. All volunteers completed nine computerized tests during the study to analyze their thinking-related skills.

Researchers concluded that Prevagen could “improve aspects of cognitive function” in individuals with typical brain-related aging or mild cognitive impairment.

Quincy claims that those who used the apoaequorin showed a “statistically significant improvement in verbal learning and recall” during the study. The researchers concluded that Prevagen could “improve aspects of cognitive function” in individuals with typical brain-related aging or mild cognitive impairment.

Bear in mind that Quincy released Prevagen in 2007 and didn’t complete this study until 2016. It subsequently used the study as the entire basis for its claims. It didn’t take long for research experts to find flaws.

Problems with Prevagen

Critics of the double-blind study say no statistically significant results were observed during the whole study population for any cognitive tasks! Also, it is alleged that Quincy Biosciences didn’t compare the apoaequorin and control groups.

In essence, the evidence claimed by the brand is nothing more than an after-the-fact (post hoc) analysis of the subgroups in the study. The suggestion is that Quincy Bioscience took inconclusive data from the research and used it to validate its theory that Prevagen helps with memory. There is no other evidence for the efficacy of apoaequorin in improving memory.

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The above allegation is fueled by the fact that Quincy Bioscience performed 30 additional analyses of the data. It found just three statistically significant results but used them anyway while ignoring the rest.

Furthermore, there are serious doubts about whether Prevagen is effective as an oral supplement in any case. It needs to survive digestion before being absorbed into the bloodstream. Next, it must pass the blood-brain barrier. Finally, Prevagen has to bind to a large enough calcium level within the human brain’s hippocampus neuron region. This is the part of the brain associated with learning and memory.

Like any orally administered drug, the effectiveness of Prevagen is limited by our metabolism. It likely has a bioavailability rate so low that it won’t have a significant pharmacological effect. The multiple issues with the product, coupled with the brand’s claims, soon led to big trouble.

Prevagen & Legal Challenges

Quincy Bioscience has been the subject of scrutiny in recent times. In 2020, the company settled a class-action lawsuit relating to allegations of false advertising.

The FTC and New York attorney general are pursuing a separate lawsuit alleging that Prevagen marketers used “false and unsubstantiated claims” about the product’s health benefits. Even though a judge dismissed the case in 2017, the ruling was vacated two years later, and the lawsuit is ongoing.

Even though it paid out on the class-action lawsuit, Quincy Bioscience denies claims of wrongdoing. However, all of the above is a consequence of a lack of regulation in the supplement industry. The FDA does not test such products for safety, nor does it approve any before sale.

This leads us to the main point of the article, whether Prevagen is safe to use.

What Are the Side Effects of Prevagen?

Unsurprisingly, Quincy Bioscience suggests that there are no severe Prevagen side effects. It has three safety studies published on its official website. The first involved using apoaequorin on rats to evaluate the ingredient’s toxicity level. It found no adverse effects at a level 4,000 times higher than the standard Prevagen dose.


The second study outlined a lack of allergic reactivity when ingested. The final study again related to the potential toxicity of apoaequorin. This time, the researchers found no adverse effects in doses of up to 16,000 times what is found in Prevagen.

At present, there is no published research showing that apoaequorin causes serious side effects. However, there is an alarming growth in the number of Prevagen users reporting the following problems:

  • Headache
  • Anxiety
  • Dizziness
  • Insomnia
  • Nausea
  • Edema
  • High blood pressure

More serious adverse effects reported by Prevagen users include chest pain, heart arrhythmias, strokes, and seizures. An internal 2015 FDA report stated that many adverse effects were reported indicating a serious safety hazard. While anecdotal evidence isn’t enough to prove the dangers of using Prevagen, it is a worrying pattern.

What About Vitamin D?

The Institute of Medicine says that the RDA of vitamin D is 600 IU for young adults and 800 IU for people aged 70+. Each Prevagen capsule contains 2,000 IU. Excessive levels of vitamin D can cause toxicity, known as hypervitaminosis D. Also, D3 is fat-soluble, so it doesn’t leave the body as readily as vitamin C.

Consuming too much vitamin D3 may lead to a toxic buildup of calcium in the body’s fat cells, causing conditions such as hypercalcemia.

Consuming too much vitamin D3 may lead to a toxic buildup of calcium in the body’s fat cells, causing conditions such as hypercalcemia. However, it takes far more vitamin D (as much as 60,000 IU a day for several months according to the Mayo Clinic) than what is in Prevagen to result in such medical issues.

Therefore, users of the supplement shouldn’t necessarily be concerned about side effects from vitamin D.

Final Thoughts on Prevagen Side Effects

Overall, the main Prevagen ingredients that could cause side effects are apoaequorin and vitamin D. The latter is unlikely to cause a toxic reaction in the levels available in Prevagen. However, there is hardly any research on the effects of the former. Quincy Bioscience claims that apoaequorin can help boost memory but can only produce one deeply flawed study as evidence.

With this in mind, it is also difficult to take the company’s safety study results at face value. At present, there is little evidence that Prevagen causes severe negative side effects. However, a growing number of users report major issues such as strokes and seizures. Remember, it is not an FDA-approved product and has not been checked for safety.

Since claims regarding the efficacy of Prevagen are dubious at best, people seeking nootropics may be better off looking elsewhere. There are many other options containing ingredients with at least a semblance of real scientific evidence to back up claims about their benefits.

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