Cerebrolysin

What Cerebrolysin is

Pig brain tissue is treated enzymatically until the large proteins are broken down into small fragments; the rest is filtered out. What remains is a clear solution containing 215.2 milligrams per milliliter. It is manufactured by EVER Pharma in Unterach am Attersee, Austria.

The decisive point: Cerebrolysin is not a defined molecule like aspirin, where one can say this is the active substance and this much is in it. It is an extract whose composition is kept constant through the manufacturing process, not through a formula. The idea behind it is that it contains neurotrophic activity — something that behaves like the body’s own growth factors for nerve cells.

What exactly in it is active remains open. A Belgian analysis of a sample bought on the internet found 638 peptides in 2015, mainly fragments of tubulin, actin and myelin basic protein, but no fragments of known growth factors. Since 2025, at least seven animal studies on Cerebrolysin from two laboratories have also been retracted; the patient studies are not affected.

What is approved

In Austria, Cerebrolysin is a prescription-only medicine with 3 indications: supportive treatment of Alzheimer-type dementia and vascular dementia, deficits after a stroke, and traumatic brain injury. It is given as an injection or infusion, not as a tablet.

It is not approved in the US. It is used mainly in Eastern Europe, Russia, China and parts of Asia, as well as in some European countries. This splits the question into two parts that otherwise get mixed up: what is approved — and what has been shown.

What the independent evaluation finds

The authoritative independent evaluation on stroke is a Cochrane review. Cochrane summarizes studies according to fixed rules and pays particularly close attention to who funded them. The current version covers 7 randomized trials with 1,773 patients with acute stroke.

Three findings, and they belong together. First, Cerebrolysin probably makes no difference to mortality — with moderate certainty of evidence and therefore reliable. Second, not a single one of the included trials provided analyzable data on how people fared afterwards: disability, independence, whether someone can manage on their own again. For a stroke medicine, that is the whole point of the exercise. Third, the evaluation found more non-fatal serious adverse events under Cerebrolysin, such as hospital admissions.

On funding, the review notes that the manufacturer supported 3 of the large multicenter trials: partly in full, partly through study drug and placebo, randomization codes, research funding or statisticians. That is not reprehensible per se — almost all drug trials are paid for by the manufacturer. It is a reason to look more closely.

Two evaluations, two impressions

In 2021, a safety evaluation of 12 randomized trials with 2,202 patients was published. Its result sounds different: serious adverse events in 7.9 percent in both groups, adverse events overall in around 43 percent in both groups. For deaths, 4.1 percent under Cerebrolysin versus 5 percent under placebo — arithmetically 17 percent fewer, not statistically confirmed.

The same substance, the opposite impression. The difference is not because someone is lying, but because of which studies are included and how an event is counted. Cochrane filtered 7 studies strictly according to a fixed protocol; the other group included 12. Including more studies dilutes an effect that is visible only in some of them. The authors of the safety evaluation declare no conflict of interest, but have been researching precisely this substance for years — not an accusation, but not the same as a team looking at it for the first time.

What the studies show

Cochrane review on acute ischemic stroke

7 randomized trials with 1,773 patients. No differences in mortality, with moderate certainty of evidence; no analyzable data on disability and independence; more non-fatal serious adverse events under Cerebrolysin. The manufacturer had supported 3 of the large multicenter trials.

Safety evaluation from 2021

12 randomized trials with 2,202 patients. Serious adverse events in 7.9 percent in both groups, adverse events overall in around 43 percent in both groups. Deaths 4.1 percent under Cerebrolysin versus 5 percent under placebo, arithmetically 17 percent fewer, not statistically confirmed.

Why the evaluations contradict each other

The difference lies in the inclusion criteria and the way events are counted: 7 strictly filtered studies at Cochrane, 12 in the safety evaluation. Including more dilutes an effect that is visible only in some; filtering more strictly makes it more likely to be found.

What the studies do not deliver

What is missing is proof that Cerebrolysin gets people back on their feet. Disability and independence are the endpoints that matter after a stroke, and on exactly these there was nothing analyzable in the body of studies examined. What is documented is that mortality does not differ. The rest is open — a different gap from that of a never-studied substance, but a gap that has stood open for decades.

Without any data at all is the use for which Cerebrolysin is bought in the nootropics scene. As a memory aid for healthy people there is neither approval nor study. All data come from sick people: acute stroke, dementia, traumatic brain injury. Added to this is the lesson that goes beyond this substance: approved does not mean proven. An approval says that an authority considered benefit and risk acceptable at a particular point in time — not that the question has been settled for all time.

Status, approval and legal

In Austria, Cerebrolysin is a prescription-only medicine with 3 approved indications and is manufactured there by EVER Pharma. It is not approved in the US; it is used mainly in Eastern Europe, Russia, China and parts of Asia, as well as in some European countries. It is injected or infused, not swallowed. If it comes into question, then in one of the approved situations and via a doctor.

Safety

In the 2021 evaluation, the safety profile looks unremarkable: 7.9 percent serious adverse events in both groups, around 43 percent adverse events overall in both groups. The Cochrane review, by contrast, found more non-fatal serious events under Cerebrolysin, including hospital admissions. On safety, then, the evaluations contradict each other. According to the Austrian prescribing information, Cerebrolysin must not be used in status epilepticus or severe renal impairment, and caution is required in epilepsy; restlessness and insomnia occur rarely. A separate point is procurement outside medical treatment: a biological preparation from animal tissue that is injected. On a gray market nobody guarantees the contents of the ampoule, and with a multi-component mixture this is much harder to check than with a single molecule.

Sources

• Ziganshina et al., Cochrane Database Syst Rev 2023 (Cochrane review on Cerebrolysin in acute ischemic stroke)
• Strilciuc et al., Pharmaceuticals (Basel) 2021 (safety evaluation of 12 randomized Cerebrolysin trials)
• Cui et al., Cochrane Database Syst Rev 2019 (Cochrane review on Cerebrolysin in vascular dementia)
• Vester et al., Neurol Sci 2021 (CAPTAIN trial series on Cerebrolysin in traumatic brain injury)
• Hartbauer et al., J Neural Transm (Vienna) 2001 (neurotrophic activity of Cerebrolysin in cell culture)
• Muresanu et al., Stroke 2016 (CARS trial on recovery after stroke)
• Gevaert et al., Drug Test Anal 2015 (peptide profile of a sample bought on the internet)
• Prescribing information Cerebrolysin, Austria (marketing authorization no. 1-21380)