Taking a vitamin B complex supplement in the morning is generally recommended by healthcare professionals and pharmacists. Because B-group vitamins play a fundamental role in energy metabolism, cellular function, and converting food into physical fuel, consuming them later in the day or right before bedtime can occasionally cause heightened alertness, vibrant dreams, or mild sleep disruptions in sensitive individuals. Taking your daily dose with breakfast or your morning meal ensures optimal absorption and sustains your physical energy levels throughout the active daytime hours.