The Cognition Research Hub

The brain is metabolically expensive. It represents a small fraction of body weight and consumes a large fraction of resting energy, and it has almost no capacity to store fuel. It depends on continuous delivery of glucose and oxygen through a dense vascular network, and on a membrane structure that is unusually rich in specific fats.

Oestrogen participates in both systems. It supports vascular function and cerebral blood flow, and it influences glucose uptake in neurons. When oestrogen falls, both the delivery system and the fuel system are affected. The subjective result is often described as brain fog, a term that captures the experience without describing the mechanism.

Brain fog is not a diagnosis and not a stage of decline. It reflects a brain doing familiar work under less favourable conditions. Distinguishing this from progressive disease matters, because the modifiable factors are different, and because much of what is attributed to ageing is attributable to sleep, circulation, and nutrient status.

Why the brain depends on specific fats

Neuronal membranes contain a high proportion of long-chain omega-3 fatty acids, particularly DHA. These are structural. They determine how fluid the membrane is, and membrane fluidity affects how efficiently receptors sit in it and how readily signals cross it.

The body cannot make DHA in useful quantities. It can convert the shorter-chain omega-3 found in plants, but the conversion is inefficient, and it is more inefficient in some people than others. This is why plant sources and marine sources are not nutritionally equivalent, even when the omega-3 content on the label appears similar.

Fats alone do not sustain cognition. Several B vitamins act as cofactors in the pathways that build neurotransmitters and manage homocysteine, and magnesium participates in the receptor systems underlying learning and memory. A structural component supplied without its metabolic cofactors does less than the research on that component suggests.

Sleep sits underneath all of it. The glymphatic clearance that removes metabolic waste from brain tissue is substantially a sleep-dependent process. No nutrient compensates for its absence.

How Silvie evaluates the evidence

We select ingredients by form, not only by name. The form determines how much of a nutrient reaches the tissue that needs it, and two products naming the same compound can differ substantially in what the body absorbs. Where a specific form has been used in the human trials, that is the form we use.

We dose to the levels tested in those published trials rather than to the smallest quantity that permits a claim on the label. A dose below the studied range is not a smaller version of the same effect. Often it is no effect at all.

We prioritise human studies. Mechanistic and animal research is useful for understanding why something might work, but it is not evidence that it does. Where the human evidence is mixed, preliminary or limited to a narrow population, we say so in the article rather than omitting it from the marketing.

We are also clear about what supplementation cannot do. Nutrients supply the structural and metabolic components. Sleep, movement and circulation determine whether the brain can use them. No formulation substitutes for those.

You can read how we assess evidence, select ingredient forms and set doses in our approach to research.