Citicoline is not a classic nutrient with a standard “deficiency diagnosis” like vitamins. In practice, people use this phrase to describe suboptimal membrane phospholipid turnover and cholinergic/dopaminergic signaling—processes tied to choline availability and neuronal membrane metabolism.\n\nSymptoms such as brain fog, reduced attention, mental fatigue, or forgetfulness rarely point to one molecule alone. A structured clinical approach should first assess sleep, stress, depression/anxiety, thyroid issues, common deficiencies (B12, iron, vitamin D), metabolic health, inflammation, and medication effects.\n\nCiticoline may be considered as supportive in select contexts, and studies report it is often well tolerated, but it is not a “must-have” supplement for everyone. Think systems-first: lifestyle + nutrition + medical evaluation, then targeted supplementation if appropriate.