Citicoline is often reported as well tolerated in studies, yet side effects can occur. Commonly reported effects are usually mild and transient: nausea, stomach discomfort, diarrhea or constipation, headache, nervousness, and occasionally sleep disturbance. Some people experience improved alertness, while others may feel jittery or notice palpitations.\n\nA practical management framework: (1) start low and increase gradually, (2) dose earlier in the day, (3) reduce caffeine/other stimulants.\n\nIf you combine multiple supplements—especially those with bleeding-interaction profiles (e.g., ginkgo with anticoagulants)—be cautious and seek clinical advice. Stop and seek care if you develop allergic symptoms, severe palpitations, fainting, marked insomnia, or significant behavioral changes.\n\nBottom line: usually mild, manageable with dose and timing; higher-risk individuals should consult a clinician.