Cypon syrup is commonly used to stimulate appetite and aid in weight gain, but it may cause some side effects. Common cypon syrup side effects include drowsiness, dry mouth, dizziness, and increased appetite, which may lead to unintentional weight gain. In rare cases, more serious effects like allergic reactions or heart palpitations may occur. If you experience any severe side effects, it's important to consult your healthcare provider to adjust your dosage or explore alternative treatments.