Cerebrolysin showed small improvements in cognition and function in vascular dementia patients, but all evidence was rated 'very low quality' due to biased, small studies — and no new trials have been conducted in years.
Very low qualityGRADE rating for all evidence — meaning the true effect could be substantially different from what these studies found
What the researchers found
This Cochrane systematic review found that Cerebrolysin — a pig-brain-derived peptide preparation given by intravenous infusion — showed statistically significant improvements in cognition and global function in people with vascular dementia, but the evidence was rated 'very low quality' across the board.
Pooling data from three studies (420 participants), Cerebrolysin improved cognitive function scores (SMD 0.36, 95% CI 0.13–0.58). For global function, response rates were 2.69 times higher in the Cerebrolysin group (two studies, 379 participants, RR 2.69, 95% CI 1.82–3.98). No excess adverse effects were found (RR 0.91, 95% CI 0.29–2.85).
However, the reviewers concluded these data are 'not definitive.' All included studies had high risk of bias, there was significant heterogeneity between studies, and no new studies had been published since the previous 2013 Cochrane review. The effects may be too small to be clinically meaningful.
Why it matters
Vascular dementia is the second most common form of dementia worldwide, yet there are essentially no proven treatments. Cerebrolysin is widely used in parts of Asia, Eastern Europe, and Russia despite weak evidence. This Cochrane review — the gold standard for evidence synthesis — delivers a clear verdict: while there are hints of benefit, the supporting evidence is too weak and too biased to justify confident use. The fact that no new trials have been conducted since 2013 suggests a stalled research agenda for a drug that continues to be prescribed to patients.
The numbers in context
6 RCTs · 597 total participants · SMD 0.36 for cognition (very low quality) · RR 2.69 for global function response (very low quality) · No excess adverse events · Follow-up 15 days to 3 years · All evidence rated GRADE 'very low'
How the study worked
This is a Cochrane systematic review (the highest standard of evidence synthesis). The authors searched 12 databases across multiple languages, checked reference lists, and contacted manufacturers. They included all randomized controlled trials of Cerebrolysin in vascular dementia patients. Two reviewers independently selected trials, assessed methodological quality, and extracted data. Meta-analyses used mean differences or standardized mean differences for continuous outcomes and risk ratios for dichotomous outcomes. Evidence strength was assessed using the GRADE framework.
Who was studied
People with mild to moderate vascular dementia across 6 RCTs conducted primarily in China, Russia, and Romania
What this study cannot tell us
Only 6 small RCTs with 597 total participants were found — far too few for definitive conclusions. All included studies had high risk of bias. Most were conducted in China, Russia, and Romania with industry funding. There was significant heterogeneity in dosing, duration, and follow-up. No studies reported on quality of life or caregiver burden. The GRADE rating of 'very low' means the reviewers have very little confidence that the true effect is close to the estimated effect. No new studies were found since the 2013 review.
How to read the evidence
Despite being a Cochrane systematic review (the highest form of evidence synthesis), the underlying evidence is rated 'very low quality' by the GRADE framework due to high risk of bias in all included studies, significant heterogeneity, small sample sizes, and imprecision. The evidence strength is rated weak because the review itself concludes the data are 'not definitive.'
When this study was published
Published in 2019 as an update to a 2013 Cochrane review. No new eligible studies were found since 2013. The conclusions about weak evidence remain current and are unlikely to change without new high-quality trials.
The bigger picture
This review highlights a troubling pattern in dementia therapeutics: drugs being widely prescribed based on weak evidence because no better options exist. Cerebrolysin continues to be promoted and used for vascular dementia despite a Cochrane review explicitly stating the evidence base is weak. The lack of new trials since 2013 suggests commercial use has outpaced scientific validation — a cautionary tale for the neuroprotective peptide field more broadly.
Questions still open
- Why have no new clinical trials of Cerebrolysin for vascular dementia been conducted since this review found the evidence insufficient?
- Are the patients currently receiving Cerebrolysin in clinical practice experiencing meaningful benefits, or is this a case of widespread use without adequate evidence?
- Could Cerebrolysin be more effective in specific subtypes of vascular dementia or at specific disease stages?
Common questions
Does Cerebrolysin actually work for vascular dementia?
Why is Cerebrolysin still used if the evidence is weak?
Read the original research
Cerebrolysin for vascular dementia.
The Cochrane database of systematic reviews, 2019(11)
Citation
Cui, Shuhui; Chen, Ning; Yang, Mi; Guo, Jian; Zhou, Muke; Zhu, Cairong; He, Li. (2019). Cerebrolysin for vascular dementia.. The Cochrane database of systematic reviews, 2019(11). https://doi.org/10.1002/14651858.CD008900.pub3