Add the sliced cucumber, frozen pineapple, milk of choice, hemp seeds, and collagen peptides to a blender.
Blend on high until smooth and creamy, about 30–60 seconds.
If the smoothie is too thick, add more milk, one tablespoon at a time, until desired consistency is reached.
Pour into a glass and enjoy immediately.
Add a few ice cubes before blending for a colder, frostier texture.
Notes
Substitutions: Use coconut water instead of milk for an extra-hydrating, mineral-rich option.
Make-Ahead Tip: Freeze blended smoothie in ice cube trays and blend with extra milk when ready to serve.
Vegetarian/Pescatarian: Use plant-based protein powder or marine collagen.