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Prevagen Review: A Detailed Look at Ingredients, Side Effects, Cost, and More

Written by Sharon Lehman, RDN

Reviewed by Anthony Dugarte, MD 

Last Updated on May 1, 2021

Our Expert Rating:


About This Rating
The average rating of this product is calculated based on the evaluation of the following factors:
  • Support for Claims:1.7
  • Ingredient Safety:4.0
  • Value for the Price:2.0
  • Brand Transparency:3.0

Prevagen is a dietary supplement designed to support brain health by improving memory. There is little evidence, other than what is produced by the company, that the active ingredient apoaequorin has an impact on brain health.

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Prevagen Review: A Detailed Look at Ingredients, Side Effects, Cost, and More


  • 45-day return/refund policy
  • Contains Vitamin D, a common deficiency
  • Accessible at major retailers


  • Insufficient evidence to support claims
  • Lacks independent third-party testing for safety and purity
  • Expensive


Prevagen is a dietary supplement designed to support brain function.

There are several variations of the product, but all Prevagen formulations contain just two active ingredients: apoaequorin and vitamin D.

The Prevagen lineup is differentiated by the amount of apoaequorin they contain. Apoaequorin is credited with helping to improve memory in older adults.

The product claims that it has been clinically proven to help improve signs related to mild memory loss that occurs with aging and that users will experience a sharper mind and clearer thinking.

The brain is the command center of the body, but most people take its numerous functions for granted since we aren’t conscious of most brain activity outside of primary thoughts, feelings, and mood.

Prevagen’s primary ingredient claims to support cognitive functioning and improve age-associated memory loss.

While it’s true that aging can impact brain health, many lifestyle factors also play a role in supporting brain function as you get older.

Your diet, sleep, physical activity, and stress levels can all contribute to brain health.

In general, anything that increases inflammation and oxidative stress results in accelerated aging.

As a registered dietitian, it’s my job to tell you that no supplement is going to make up for or erase the inflammatory effects caused by an unhealthy diet, smoking, excessive alcohol use, poor sleep, or lack of physical activity.

Evaluation of Ingredients

Prevagen contains just two active ingredients: apoaequorin and vitamin D:


Apoaequorin is a calcium-binding protein discovered in a species of bioluminescent jellyfish found in the Pacific Ocean.

Regular strength Prevagen contains 10 mg of apoaequorin, and the extra strength and professional strength formulations contain 20 mg and 40 mg, respectively.

Prevagen’s marketing repeatedly tells consumers just how unique and clinically proven to be safe this ingredient is.

The details of how anyone made a connection between a substance found in one species of jellyfish floating around the ocean and the human brain is beyond me, but let’s take a look at the so-called evidence.

The product claims this ingredient has been clinically proven to improve memory and support brain function and works by regulating the amount of calcium in brain cells.

Calcium plays an important role in memory and neurotransmitter production.

I took a look at the “science” tab on Prevagen’s website, where they list several studies to support their claims of safety and efficacy.

The studies cited on Prevagen’s site tested high doses of apoaequorin on lab rats.

Since the amounts given to the rats were several thousand times higher than the amount in Prevagen, they deemed the ingredient safe for human consumption.

They also cite a single study that used simulated digestion to determine if apoaequorin is broken down by pepsin, the main digestive enzyme in the stomach, and therefore would be unlikely to cause an allergic reaction in humans.

The fact that this ingredient is broken down in the stomach makes me wonder how it can reach the brain to do any good. Again, this determination was made without testing on humans.

As for efficacy, the only clinical evidence that exists is the Madison Memory Study which was conducted by the makers of Prevagen and is an immediate red flag in my book.

Prevagen references this double-blind placebo-controlled trial often to drive home the point that apoaequorin has been clinically studied and proven effective.

The language sounds scientific and legit, but there are some issues.

The study involved a scant 218 adults between the ages of 40 and 91 with self-reported memory concerns.

Individuals who received Prevagen over placebo for 90 days showed significant improvement in verbal learning, working memory, and memory recall based on computer testing.

Since this study was conducted internally by the makers of Prevagen, these findings are subject to bias and should be taken with a grain of salt.

No clinical tests or imaging have been performed to indicate that ingesting apoaequorin does indeed result in an increase in the amount of calcium in brain cells or increased brain activity.

A further dive into the research found no other studies on this ingredient.

The bottom line? There have been no studies regarding the safety of apoaequorin when ingested by humans, and the claims to improve cognitive function and memory are lofty promises without sufficient evidence to support them.

Vitamin D3

All formulations of Prevagen contain 50 micrograms (mcg) of vitamin D3 per serving as cholecalciferol.

The Recommended Dietary Allowance for vitamin D is 15 mcg per day for adults aged 19–70 years and 20 mcg per day for adults 71 years and up.

Vitamin D plays a role in brain health. There is evidence suggesting adequate vitamin D intake can support brain function during aging, and deficiency is linked to increased incidence of brain disorders like depression, dementia, and autism.

Verdict on Claimed Benefits

Below is our summary of the available evidence for the claimed benefits of Prevagen based on the available research:

  • Healthy brain functionModerate Evidence
  • Sharper mindNo Evidence
  • Clearer thinkingNo Evidence

Side Effects, Safety, and Dosage

The serving size for Prevagen is 1 tablet per day, no matter which formula you select. It’s recommended to take Prevagen in the morning with or without breakfast.

Although Prevagen has been around for years, I question the long-term safety of this ingredient.

The only scientific study involving human consumption was conducted by the makers of Prevagen, although they did report it was well tolerated with no noteworthy side effects.

It’s worth noting that you could be taking too much vitamin D if you pair Prevagen with another supplement that contains vitamin D.

Each Prevagen product contains 50 mcg of vitamin D per dose. The upper daily limit for vitamin D is set at 100 mcg, which is the maximum daily amount unlikely to cause adverse effects.

Some prescription medicines may be less potent when you supplement with too much vitamin D, including cholesterol-lowering statins.

If you’re considering trying Prevagen, speak with a healthcare professional beforehand.

Cost and Where to Buy

Prevagen is sold at most major retailers, grocery stores, and drug stores, including Amazon, Target, Walmart, Walgreens, and CVS.

Prevagen makes three formulations, but how do you know which one is right for you?

Because apoaequorin hasn’t been studied for human consumption, there are no recommended intakes.

The makers of Prevagen leave it to the consumer to decide the right amount, and my guess is they’re hoping most buyers will fall into the “more must be better” mentality.

  • Regular strength Prevagen costs $40 for a 30-count bottle and $75 for a 60-count bottle.
  • Extra-strength Prevagen is also available in 30 or 60 counts and costs $60 and $110, respectively.
  • The professional strength Prevagen costs $90 for a 30-day supply.

If you don’t like swallowing tablets, the regular and extra-strength formulas are also available as chewables and cost the same as the tablets.

Prevagen has a 45-day return and refund policy for any of their products as long as you purchase from an authorized dealer and retain the original receipt and product packaging.

You can find complete refund instructions and a list of authorized retail locations on their website.

Buy Prevagen on Amazon

Comparison to Alternatives

Prevagen is the only memory supplement that contains apoaequorin, so there’s not much to compare it to.

Other top-selling memory and brain health supplements contain a variety of evidence-backed active ingredients, including B vitamins, mushrooms, and herbal ingredients like Ginkgo biloba and Rhodiola rosea.

It’s hard to say if the price of Prevagen is fair since it is the only brain health supplement that contains apoaequorin.

However, it’s overpriced compared to DHA/EPA (i.e., omega-3 fatty acid) supplements that are well-studied and proven to benefit brain health.

Related: Prevagen vs. Neuriva: What’s the Difference

The Bottom Line

There isn’t enough evidence to support claims that apoaequorin, the active ingredient in Prevagen, can improve memory, let alone support brain health in any significant way.

Its long-term safety is also questionable since this ingredient has only been tested for safety in lab rats.

Prevagen has come under fire with the Federal Drug Administration and Federal Trade Commission for some of their claims which have violated what is permissible by law for a dietary supplement.

Prevagen also contains 250% of the Recommended Dietary Allowance for Vitamin D for adults over 71 years.

Vitamin D supplementation can be beneficial for the aging body and mind, but you don’t need to take a Prevagen to get your daily dose of D.

If you’re considering taking Prevagen, I would advise you to proceed with caution and speak with a healthcare provider before doing so.

A Word from Our RD

Instead of entrusting the health of your brain to a so-called wonder ingredient originally found in jellyfish, I recommend focusing on improving lifestyle factors that can contribute to healthy brain functioning.

These include:

  • Being physically active on a regular basis.
  • Getting 7-8 hours of sleep each night.
  • Enhancing mindfulness through breathwork and meditative practices.
  • Avoiding mind-altering substances like alcohol and drugs.
  • Eating a healthy diet that includes plenty of fruits, vegetables, whole grains, and wild-caught fish and limits sugar, refined carbohydrates, and unhealthy fats.
  • Engaging in brain-healthy activities, like puzzles, reading, and learning new skills.
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