Emerging therapy

Peptide preparations

Cerebrolysin, Cortexin, Semax, and “peptide therapy” sold by wellness clinics

Two quite different things share this word: prescription neuropeptide preparations used routinely in some countries, and an unregulated wellness trade. Neither has good evidence in children.

Where it stands, condition by condition

The same therapy can be well supported for one problem and completely untested for another. This is the single most common place families are misled.

What it is

A peptide is simply a short chain of amino acids. The word therefore covers everything from a licensed hormone to a powder bought online, which is precisely why it is such a useful marketing term.

In paediatric neurology the ones families actually meet are neuropeptide preparations — Cerebrolysin, Cortexin, Semax and similar. These are given by injection or nasal spray in courses, often repeated two or three times a year.

Cerebrolysin is a mixture of low-molecular-weight peptides and amino acids derived from pig brain tissue. It is a prescription medicine in a number of countries and is not licensed in others, including the United States.

Separately, private clinics sell “peptide therapy” — individual synthetic peptides marketed for repair, recovery or growth. That is a different trade with a different, weaker footing, and it should not borrow credibility from the prescription products.

How it is meant to work

The claim is neurotrophic: that these mixtures mimic naturally occurring growth factors, protect neurons under stress and encourage plasticity.

There is real laboratory work behind that claim. The difficulty is that a mixture of many peptides with no single active ingredient is almost impossible to standardise or to dose rationally, and the same batch-to-batch question that dogs exosomes applies here.

Most of these peptides are also large, fragile molecules. How much reaches the brain after injection, and in what form, is not well established.

What has actually been tested

• Cerebrolysin in adult ischaemic stroke is the best-studied use and the honest summary is that experts disagree. The Cochrane review (Ziganshina and colleagues, updated 2023) concludes with moderate certainty that it probably does not reduce death from any cause, and reports a possible increase in non-fatal serious adverse events (relative risk about 2.39, 95% CI 1.10 to 5.23), while total serious adverse events did not clearly differ (RR about 1.16, 95% CI 0.81 to 1.66). The same review covers Cortexin.
• Other systematic reviews, pooling more trials, report no increase in serious adverse events and moderate-certainty evidence of modest early neurological improvement on the NIHSS scale. Part of the disagreement comes from which outcomes are counted.
• The Cochrane authors also note that data for several included trials came from the manufacturer, which they treated as a likely conflict of interest.
• All of that is adult stroke. For children with cerebral palsy, developmental delay or autism, the evidence is substantially weaker: small studies, frequently unblinded, often without a control group, and reported mainly in regional literature.
• For the wellness peptides there is essentially nothing in children — no registered paediatric neurological trials, and no regulatory approval anywhere.

What we still do not know

• Whether any benefit seen in adult stroke transfers to a developing brain, or to a chronic condition rather than an acute injury.
• What a course should contain, how often it should be repeated, and for how long — current practice is convention rather than evidence.
• Long-term effects of repeated courses through childhood.
• What is actually in a given vial, for products made outside strict pharmaceutical control.

Risks and costs

• Injection-related: pain, local reactions, and in young children the distress of repeated courses.
• Hypersensitivity reactions, which are recognised with animal-derived preparations.
• The Cochrane signal on non-fatal serious adverse events is not proof of harm, but it is not nothing either, and it is rarely mentioned when these courses are recommended.
• For wellness peptides: unknown purity, unknown dose, no oversight, and in sport an anti-doping problem for older children.
• Cost and repetition. Courses are typically sold two or three times a year, indefinitely.

Questions to ask before you agree

1. Is this a licensed medicine in this country, and licensed for what?
2. What paediatric evidence exists for my child's condition — not adult stroke data?
3. What exactly will improve, how will it be measured, and when do we decide it has not worked?
4. If this is a synthetic peptide from a private clinic rather than a pharmacy medicine, who manufactured it and under what standard?

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