No, it is generally not necessary to use both vitamin D injections and tablets at the same time. Typically, your doctor will prescribe only one method based on how low your levels are and how well your body absorbs nutrients. Oral tablets (cholecalciferol) are highly effective and the most common treatment. Injections are usually reserved for very severe deficiencies or cases where stomach issues prevent pill absorption. Taking both together without direct medical supervision is rarely needed and could lead to excessively high vitamin D levels. Your doctor will help you choose the single best option for your body.