The most common side effects with Thymanax (seen in between 1 and 10 patients in 100) are headache, dizziness, somnolence (sleepiness), insomnia (difficulty sleeping), migraine, nausea (feeling sick), diarrhoea, constipation, upper abdominal pain (tummy ache), hyperhidrosis (excessive sweating), back pain, fatigue (tiredness), increases in liver enzymes and anxiety.