Cerebrolysin is a mixture of peptides derived from the brains of pigs. It is approved in many European and Asian countries as an injection for treating stroke, traumatic brain injury, and dementia. It is not, however, approved for use in the United States and a large 2012 trial casts doubts on its usefulness in stroke, except perhaps in severe cases. It remains unknown if cerebrolysin might prevent dementia or slow cognitive decline. Studies suggest cerebrolysin is generally safe.
Many clinical trials have been carried out in people with dementia, but the evidence is limited for healthy adults and no studies have tested whether cerebrolysin can prevent dementia. Our search identified:
• 3 meta-analyses of randomized controlled trials in patients with Alzheimer's or vascular dementia
• 0 clinical studies on dementia prevention or cognition in healthy adults
• 6 randomized controlled trials (4 in Alzheimer’s patients, 1 testing a component of cerebrolysin in older adults with memory problems, and 1 in schizophrenia patients)
• 1 uncontrolled clinical trial testing acute effects in healthy elderly people
• Numerous preclinical studies
A few small clinical trials have reported that cerebrolysin can improve cognitive function in older people with memory problems and in those with schizophrenia, although the effects are modest. In a trial with schizophrenia patients, cerebrolysin treatment improved cognition and memory . Another trial of older adults with memory loss found that a peptide preparation derived from cerebrolysin improved memory performance but not verbal fluency . The effect on memory was lower than that of currently approved drugs for Alzheimer's disease. An uncontrolled clinical trial reported that healthy elderly people had better memory performance after one dose of cerebrolysin but this result could have been caused by the placebo effect .
No clinical studies have tested whether cerebrolysin can prevent dementia, but some preclinical research supports the idea. In preclinical studies, cerebrolysin protected neurons and brain slices from damage , reduced inflammation , promoted the formation of new neural connections (synapses) , lessened cognitive impairment , and reduced the plaques and tangles common in Alzheimer’s patients . Whether these effects will occur in humans is unknown.
The evidence is mixed and limited on whether cerebrolysin selectively affects APOE4 carriers versus non-carriers. In one trial, Alzheimer's patients without an APOE4 allele were about three times more likely to respond to treatment than APOE4 carriers . But another randomized trial reported that in APOE4 carriers, cerebrolysin was more effective at increasing the level of a protein that enhances brain cell growth and survival . For more information on what the APOE gene allele means for your health, read our APOE4 information page.
Based on many small trials, cerebrolysin has an overall beneficial effect on cognitive function in patients with mild-to-moderate Alzheimer's disease  and patients with vascular dementia . It may also be useful in combination with donepezil . However, these results have not been confirmed yet in larger, randomized, well-controlled trials and the drug is not approved for use in the United States. Cerebrolysin must be delivered through injections. Because cerebrolysin is derived from pig brains, effects may vary depending on the content and concentration of each preparation.
Results from a meta-analysis along with multiple clinical trials suggest that cerebrolysin is safe for use up to three years with few adverse effects that are usually temporary and include headaches, weight loss, dizziness, anxiety, agitation, and feeling hot . The rates of adverse effects were comparable between people receiving cerebrolysin versus placebo. However, the process of injection always carries some risks. Because cerebrolysin is purified from animal tissue, there is a risk of bacterial, viral, or fungal contamination of the product. There is very little information on potential harmful interactions with other medications.
NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.
Cerebrolysin is not approved in the United States for the treatment of any condition. Although sometimes sold for use orally (by mouth), peptides like those in cerebrolysin are typically broken down in the gut without ever reaching the body or brain, and are thus given through injection. In clinical studies, doses of 30 ml/day, delivered intravenously for 4 weeks produced some positive results, and higher doses may be less effective . The content and concentration may vary by manufacturer and by batch.
The Cochrane Library summarizes clinical trial results of cerebrolysin in patients with vascular dementia and acute ischemic stroke.