When you drink store-bought grapefruit juice, the sugars and preservatives that are added to it reduce its nutritional value. Making the juice yourself ensures that you'll get the full health benefits of the fruit. Using a blender, not a juicer, is crucial to this; a juicer removes much of the pulp from the fruit, which contains the majority of its nutrients.
Peel the rind from the grapefruit. It should come away easily. Use a grapefruit knife to dig out the sections of the fruit if you have difficulty.
Put the peeled grapefruit into the blender.
Add one cup of cold water.
Add one tbsp. of honey to reduce the juice's bitterness.
Blend the contents for one minute on high speed until they are thoroughly liquefied.
Serve in a tall glass that will hold all of the juice. Drink it as soon as possible so it doesn't lose its vitamins.