Yes, it is possible. Methylcobalamin (Vitamin B12) and other B-complex vitamins in your multivitamin can boost your energy levels and brain alertness. Taking them late in the day or evening can interfere with your natural sleep cycle, causing insomnia. To help improve your sleep, try taking both supplements in the morning with your breakfast. This allows your body to utilise the energy boost during the day without disrupting your rest at night. If your sleep issues persist after switching to morning doses, please consult your doctor to discuss adjusting the dosage. This is a very common and easily manageable issue, so there is no need to worry.