DHA-conjugated phosphatidylserine (PS) is used to support the cholinergic (acetylcholine) system primarily based on scientific rationale, though the evidence is moderate rather than strong. Phosphatidylserine is a phospholipid found in cell membranes, especially in neuronal tissue, and is involved in membrane fluidity and cell signaling. Studies have shown that PS supplementation can improve cognitive functions, especially in elderly populations and those with cognitive decline. The conjugation with DHA (docosahexaenoic acid), an omega-3 fatty acid abundant in brain tissue, is thought to further enhance these effects by supporting membrane composition and function.

The connection to the acetylcholine system is indirect but plausible. PS has been shown in animal and some human studies to increase the availability of acetylcholine, a key neurotransmitter involved in memory and learning. It may do this by supporting the synthesis and release of acetylcholine in neurons. For instance, some preclinical studies suggest that PS supplementation can increase acetylcholine release in the hippocampus, a brain region critical for memory. However, most human studies focus on general cognitive effects rather than direct measures of acetylcholine activity.

Overall, while there is scientific rationale and some supporting evidence for the use of DHA-conjugated PS to support acetylcholine-mediated functions, direct evidence specifically linking it to the acetylcholine system in humans remains limited. Thus, the evidence level is moderate (3/5).