CCL11 Blockade dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
CCL11 Blockade is a signalling protein that rises with age in human blood and harms new brain cell growth in mice. There is data in people linking it to thinking skills, and no trial of blocking it in anyone.
Evidence grade for CCL11 Blockade: Preliminary. The rule: studied in people, but no published study has had people take it. The sum on this page: 2 human studies where nobody was given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 0
- Human studies
- 0
- Found nothing
- 0
Dose
No human dose established
No published study on this page has given this compound to people and reported a result.
2 human studies where nobody was given it
5 effects reported, 4 unwanted, 1 wanted, by people using it, not a trial
Goal pages: Brain, memory and mood
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
CCL11 is a signalling protein that rises as you get older. In mice it slows the growth of new brain cells. Blocking it is the idea. Nobody has built the drug.
What people take it for
- Protecting memory as they age.
- Lowering an ageing marker, if a way existed.
What studies in people showed
Nobody has run a trial of blocking this in a person. In people, all we have is watching. In 833 older adults across two French groups, country dwellers had much higher levels, a middle value of 145 against 103. Among them, higher levels went with worse scores on a memory and thinking test. Among city dwellers they did not. Everything was measured at one moment, so nothing shows which way cause runs. It can also be measured in transfusion blood bags, and there is more of it when the donor is older. In mice, injecting it slowed new brain cell growth and harmed learning and memory.
What people report
Reports, not study results
The good
- We have not collected user reports on this one yet.
- There is no product, so nobody is reporting on one.
The bad
- Nobody has blocked it in a person, so nothing is known about whether that is safe.
- It calls in a type of white blood cell. Blocking it would knock on to allergy and to fighting parasites.
- The human link showed up in one of two groups and not the other.
- It rises with inflammation generally, and inflammation itself goes with worse thinking.
Where these come from: The population numbers and blood bag finding come from the human studies on this page. The mouse results come from the animal studies here. No user reports exist.
My bottom line
A real ageing marker with no treatment behind it. Fifteen years on, that gap tells you something.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals CCL11 Blockade has been tested for in people, biggest studies first. We count only what the studies on this page say, so the real numbers may be higher.
- Memory and thinking833 people · 1 study
35 of the 36 indexed goals have no study of any kind behind CCL11 Blockade
No study in people, animals or cells on this page reports a result for these. That does not prove CCL11 Blockade does nothing for them. It does mean anything you have heard about CCL11 Blockade and one of these did not come from a study cited here.
Show full evidence
What is CCL11 Blockade?
CCL11 Blockade is a signalling protein that rises with age in human blood and harms new brain cell growth in mice. There is data in people linking it to thinking skills, and no trial of blocking it in anyone.
Nobody has run a trial of blocking CCL11 in a person. Lowering or mopping up this protein is an idea, not a treatment.
The human record is observation only. In a 2018 study across two French groups, 515 city dwellers and 318 country dwellers had their blood CCL11 measured and took a standard memory and thinking test. Country dwellers had much higher levels: a middle value of 145 against 103 picograms per millilitre. After allowing for other differences, higher CCL11 went with worse scores in country dwellers, and not in city dwellers. That split is the honest finding. There is a link in one group and not the other, and everything was measured at one moment, so nothing can say which way cause runs.
One more human observation matters in practice. CCL11 can be measured in the blood products hospitals transfuse, and there is more of it when the donor is older. That was reported in 2017.
CCL11, also called eotaxin-1, came from the 2011 Nature study that started this field. In mice, joining a young animal's blood supply to an old one showed that something in old blood slows new brain cell growth and harms learning and memory in the young animal. Screening for what, the authors found signalling proteins including CCL11. Its blood levels tracked with less new brain cell growth in those joined mice and in old mice. It was also higher in the blood and spinal fluid of healthy ageing people. Then came the step that shows cause: injecting CCL11 into young mice, outside the brain, slowed new brain cell growth and harmed learning and memory.
How does CCL11 Blockade work?
In mice, raising CCL11 in the body slows the growth of new brain cells in the memory centre and harms learning and memory. Lowering it explains part of why a livelier, more interesting cage helps an old mouse's brain. In people, the known biology is ordinary immune biology. CCL11 calls in a type of white blood cell, the eosinophil, through a receptor called CCR3. It is central to allergy and to diseases driven by those cells. How that job connects to the thinking-skill links seen in people has not been worked out, and no treatment in people has tested it.
What have studies in people found about CCL11 Blockade?
Observation only. CCL11 has been measured in human blood, spinal fluid and donated blood products. Higher levels went with worse thinking scores in one of two groups studied together. Nobody has been given anything to block CCL11 for ageing or thinking.
- Experimental Gerontology 2018: 833 older adults living at home, across two French groups. Blood CCL11 was much higher in country dwellers, a middle value of 145 picograms per millilitre against 103 in city dwellers. After allowing for other differences, higher CCL11 went with lower scores on a standard memory and thinking test in the country group, and not in the city group.
- The 2011 Nature paper reports that CCL11 is higher in the blood and spinal fluid of healthy ageing people. That is a human measurement inside an otherwise animal study.
- Frontiers in Aging Neuroscience 2017: CCL11 can be measured in transfusion blood products, and there is more of it when the donor is older.
- No study has given people anything to block CCL11 for ageing or thinking. None is registered and none is published.
What this does not tell you: A link found at one moment, in one of two groups, is weak evidence, and the authors say so. It cannot tell you whether high CCL11 causes thinking to decline, whether declining thinking raises CCL11, or whether something else raises both. CCL11 is an inflammation signal and tracks with inflammation generally, which is itself linked to worse thinking. Nobody has blocked it in a person, so nothing is known about whether that is safe or useful. And a signal this central to calling in white blood cells would not be blocked without knock-on effects for allergy and for fighting parasites.
The state of the research
CCL11 was the first ageing blood factor anyone named, and it is the reason this half of the field exists. So its record is worth reading closely. In people, the evidence is measurement only. In mice, the cause and effect is real: injecting CCL11 into young mice harmed new brain cell growth and memory, and lowering it explains part of the benefit of a livelier cage.
What has not happened in fifteen years is a trial of blocking it. There is a likely reason. Drugs that block CCL11 or its receptor were built for allergy and for diseases driven by a type of white blood cell, which is a far clearer path to a sale than ageing. Reusing one for ageing would need a measure and a trial size nobody has paid for. That explains a thin record. It is not a finding that blocking it would fail, and it is not evidence that it would work.
The transfusion finding deserves its own mention, because it is the one part of this work with an immediate practical edge. CCL11 is present in banked blood products, and there is more of it when the donor is older. That is about a product millions of people receive. No effect on patients has been shown from it, either way.
The evidence, in charts
Fig. 1a · how many people
833people, across 1 study in people cited here
| Study | People | Share |
|---|---|---|
| Experimental Gerontology 2018 | 833 | 100% |
The whole total is one study of 833. Counts are the number of people each study on this page says it signed up. That includes studies that only watched people and gave nobody the compound. 1 more study in people gives no headcount and is not counted here. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
2 of 4 sources here are studies in people. The rest are not.
- Study in people · done in people250%
- Animal study · done in animals250%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
The studies cover 4 different years, 2011 to 2021, counted from the list of sources on this page.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Biologic
- Molecule weight
- Not on file
- Half-life
- None on file
- Chain length
- None on file
No amino acid sequence is on file for CCL11 Blockade, so none is drawn rather than guessed from a name.
The studies we cite
- Study in people2018Association between plasma CCL11 (eotaxin-1) and cognitive status in older adults: Differences between rural and urban dwellers
Nobody was given anything here. Researchers measured CCL11 in the blood of 833 older people living at home, 515 in the city of Bordeaux and 318 in the countryside. Country dwellers had higher levels. Among them, higher CCL11 went with worse scores on a standard memory and thinking test. Among city dwellers it did not. Everything was measured at one moment, so there is no way to tell whether the chemical harmed anyone's thinking or simply travelled with something else.
833 community-dwelling older adults: 515 urban from the 3C-Bordeaux cohort and 318 rural from the AMI cohort, with plasma CCL11 by immunoassay and Mini-Mental State Examination as the cognitive measure. CCL11 was higher in rural dwellers, median 145 pg/mL (IQR 115 to 201) versus 103 pg/mL (IQR 85 to 129), p < 0.001. After adjustment, CCL11 was negatively associated with cognitive performance in rural dwellers but not in urban dwellers. Cross-sectional, so direction of effect cannot be established.
- Study in people2017The "Aging Factor" Eotaxin-1 (CCL11) Is Detectable in Transfusion Blood Products and Increases with the Donor's Age
The ageing chemical people worry about is already in the blood bags hospitals use. Researchers measured CCL11 in transfusion blood products and found it there. The older the donor, the more of it the product carried. Nobody was treated and nobody was followed. This is a measurement of a widely used medical product, and it is the reason donor age gets discussed in this field at all.
Human blood products. CCL11 is detectable in transfusion blood products and its concentration increases with the age of the donor. A practical human observation about a widely used medical product, and the reason donor age is discussed in this field at all.
- Animal study2011The ageing systemic milieu negatively regulates neurogenesis and cognitive function
In mice, with one human measurement inside it. Giving a young mouse the blood supply or plasma of an old mouse made its brain adapt less well and harmed learning and memory. The signalling protein CCL11 was picked out. Its blood levels tracked with less new brain cell growth, and it is higher in the blood and spinal fluid of healthy ageing people. Injecting it into young mice slowed new brain cell growth and harmed memory. Funded by the US National Institutes of Health.
Mouse, with a human measurement component. Heterochronic parabiosis showed that an old systemic environment or plasma from old mice decreased synaptic plasticity and impaired contextual fear conditioning and spatial learning in young mice. CCL11 was identified as a chemokine whose plasma levels correlated with reduced neurogenesis, and which is increased in the plasma and cerebrospinal fluid of healthy ageing humans. Increasing peripheral CCL11 in young mice decreased neurogenesis and impaired learning and memory. NIH funded.
- Animal study2021Reduced ccl11/eotaxin mediates the beneficial effects of environmental stimulation on the aged hippocampus
In mice, lowering CCL11 explains part of why a livelier, more interesting cage helps the memory centre of an old brain. That is the strongest evidence that lowering this protein is the thing doing the work, rather than just something that moves alongside it.
Mouse. Reduced CCL11 mediates part of the benefit of environmental enrichment on the aged hippocampus, which is the strongest causal evidence that lowering this chemokine is the operative change rather than a correlate.
Common questions
Has CCL11 Blockade been tested in people?
Not in a completed trial cited here. 2 human studies where nobody was given it. CCL11 Blockade is a signalling protein that rises with age in human blood and harms new brain cell growth in mice. There is data in people linking it to thinking skills, and no trial of blocking it in anyone.
What is the CCL11 Blockade dosage?
No human dose established. No published study on this page has given this compound to people and reported a result. 2 human studies where nobody was given it
Is CCL11 Blockade FDA-approved?
No therapy that blocks CCL11 is approved for any use, and none is in a registered study for ageing or thinking skills. CCL11 can be measured in research labs and hospital labs.
Does CCL11 cause cognitive decline in people?
Not shown. CCL11 rises with age in human blood and spinal fluid, and one study of 833 older adults found higher levels went with lower thinking scores in country dwellers but not city dwellers. That link was measured at one moment, in one of two groups, so it cannot show cause. The cause and effect evidence, that raising it harms new brain cell growth and memory, is in mice.
Can you block CCL11?
Not as a treatment anyone has tested for ageing. No CCL11-blocking treatment is approved for anything, and no trial of blocking it for thinking or ageing is registered. The idea exists. The treatment does not.
Does donor age matter for a blood transfusion?
CCL11 can be measured in transfusion blood products, and there is more of it when the donor is older. That is a measured fact in people. No effect on patients has been shown from it, in either direction, and transfusion practice is not based on it.