Advantages:
1. Convenience similar to protein RTDs. Faster-acting liquid delivery form, though not as fast as protein RTDs.
2. Do not require mixing or any other preparation.
3. Varieties not limited to fruit flavors like protein RTDs.
4. Thicker, more filling consistency.
5. Typically milk-protein based, so they're rich in anti-catabolic, slow-release casein. Unless added, minimal carbohydrates and fat.


Disadvantages:
In many respects. RTD protein shakes share disadvantages with protein RTDs.
1. They require refrigeration for best flavor, are relatively heavy for their size, and are more expensive than other protein sources.
2. Unlike   protein   RTDs.   ready-to-drink protein shakes use heat, rather  than acids, to preserve freshness and ensure safety. This allows for a larger variety of flavors (everything from vanilla and  chocolate to fruit punch and grape), but also limits the types and levels of proteins that can be used to those  that are stable at higher temperatures.
3. Thicker, more-filling  consistency is beneficial for weight loss, but  may limit hardgainers by filling them up too much.
Best time to Use:

With the chickens or the night owls Taken at bedtime, the casein-containing milk proteins supply your muscles with a steady stream of essential amino acids throughout the night. This makes RTD shakes highly protective of hard-earned skeletal muscle (a.k.a.  anticatabolic).  Additionally, the  slow-burning
energy in these shakes helps keep ravenous morning hunger at bay so that you don't sabotage your leanness by overeating.
RTD protein shakes are also a great way to start the day. They're   quick, they're nutritious, and when compared with a meal from any fast food place, they're very economical. Many RTD protein shakes even include vitamins and essential minerals, making them a near-perfect protein source for people who always seem to come up with excuses as to why they skip breakfast.