Prevagen Lawsuit Alleges Memory Supplement Caused Seizures and Neurological Injuries

After taking Prevagen supplements, couple both suffered injuries that they blame on a lack of adequate warnings and testing.

A California couple has filed a product liability lawsuit alleging Prevagen, a supplement advertised to have brain benefits, caused them to suffer severe neurological side effects, including strokes and seizures.

The complaint (PDF) was brought by Juanita Hopson and Stevenson Hopson in Riverside County Superior Court on December 18, 2025, and was removed to the U.S. District Court of California on June 29. It names Prevagen Inc., Amazon.com Sales Inc. and GNC Holdings LLC as defendants.

The Hopsons allege Prevagen is a dangerous and defective supplement that is harmful to consumers, which the makers should have known from their own clinical testing.

Prevagen Health Claims Questioned

Prevagen is a dietary supplement marketed to improve cognitive function and improve brain health. It claims to include a protein derived from jellyfish to improve memory and other cognitive symptoms.

In recent years it has come under fire by the Federal Trade Commission for making advertising claims that cannot be proven by medical or scientific research. These include claims that it improves memory and prevents conditions like Alzheimer’s disease.

Despite these advertised health benefit claims, the Hopsons’ complaint is one of several Prevagen lawsuits filed over the past decade, accusing the manufacturer of deceptive marketing and profiting from misleading health claims. In addition, the manufacturer faces a class action Prevagen lawsuit filed last year over allegations the supplement does not protect the brain against Alzheimer’s, dementia or other forms of memory loss, despite advertising claims.

Prevagen Neurological Injury Allegations

The Hopsons’ lawsuit indicates they purchased Prevagen through the product’s official online store, as well as from Amazon and GNC, on December 25, 2023. After Stevenson began taking the supplement as directed and using it regularly, he allegedly developed neurological symptoms, including confusion, blurred vision, garbled speech and a temporary inability to speak.

The 87 year old then suffered a transient cerebral ischemic stroke on May 6, 2024. He suffered three more strokes and partial seizures on May 7, 9, and 10 of that year.

According to the complaint, Stevenson lost consciousness several times, suffered expressive aphasia, left arm weakness, confusion, and required multiple emergency hospitalizations. He eventually suffered permanent neurological injury, permanent partial epilepsy, left temporal lobe abnormalities in the brain, and now requires anti-seizure medication and ongoing neurological monitoring.

Juanita also began suffering side effects after taking the supplement. She experienced confusion, brain fog, severe headaches, irritation, memory loss, dizziness, cognitive dysregulation and neurological abnormalities.

The complaint alleges the supplement was not adequately tested to determine the full side effects. Furthermore, the lawsuit claims the defendants failed to warn consumers of neurological risks and did not disclose safety concerns of stroke, seizures and brain injury.

“Defendants knew, or by means of available scientific knowledge should have known, of the numerous other earlier deaths, injuries, consumer complaints, warranty claims and lawsuits caused by the defective Prevagen, including earlier versions and similar products, due to the inadequate and improper design, defective manufacturing and lack of proper warnings.”

— Juanita Hopson et al. v. Prevagen Inc. et. al.

The lawsuit raises claims of negligence, strict product liability, failure to warn / negligent recall and violations of the California Consumer Legal Remedies Act.

The Hopsons are seeking damages for medical expenses, pain and suffering, neurological injuries, cognitive impairment, loss of consciousness, hospitalization, ongoing medical treatment, punitive damages and attorney’s fees.

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