Can You Refrigerate Protein Shakes Overnight | How Long?

There’s nothing better than waking up to your clothes already laid out, work stuff packed, and shoes by the door. Convenience makes the early morning routine much easier and sets the stage for a productive day.

Most people don’t have time to not only cook breakfast in the morning, but sit down and eat it. Many health conscious individuals will opt for a protein shake or protein bar and have it on the run instead.

If you really want to save time, you may wonder if you can premix a protein shake the night before and have it in the morning.

A protein shake will not lose its integrity if it’s refrigerated overnight. There may be some slight separation which requires shaking before drinking it. However, the nutritional benefits remain the same.

Think of all the RTD (ready-to-drink) products you see in vitamin stores and supermarkets. They are premixed and last for months on the shelf. While some of them do contain preservatives to keep them shelf stable, it’s not all that different from making a shake the night before and leaving it in the fridge.

The one exception is if the shake contains creatine. Some people like to add creatine monohydrate to their protein shakes. However creatine becomes unstable when mixed in liquid over a period of time. Therefore, we would not recommend leaving a protein shake containing creatine in the refrigerator overnight.

Beyond that, there are no limitations to premixing a protein shake and leaving it overnight. Even if you blend in fruit, peanut butter, or coconut oil, at worst you’d just have to give it a shake the next morning before drinking it.

When you consider the popularity of overnight oats, the idea of leaving a protein shake in the fridge overnight is completely logical. Overnight oats are a concoction of healthy foods, usually including protein powder, mixed into a jar and left in a refrigerator.

If something like that can stay fresh overnight, then a protein shake will maintain itself perfectly fine.

How Long Can You Keep Protein Shakes in the Refrigerator?

Naturally, there are limits to anything. You can’t expect to premix a protein shake and drink it months later.

You can leave premixed protein shakes in the fridge for 48-72 hours; beyond that you’re pushing it. This is more from a quality perspective rather than a safety perspective.

It’s unlikely you’d get sick if you consumed the shake past that time frame, but it probably wouldn’t taste very good.

When foods are exposed to oxygen, they begin to degrade. This is why fresh fruit goes bad far more quickly than canned fruit. Canned fruit is sealed in a container while fresh fruit is out in the open. People have jokingly commented about how foods like avocados are fresh for a ridiculously short period of time.

While a protein shake is enclosed in a shaker bottle, it’s not as if it is perfectly sealed. There is still some air getting in so the ingredients will break down slightly. Again, a few days are no issue but beyond that the quality will suffer.

Best Type of Protein Powder to Premix

While there are no limits to the type of protein you can mix overnight, some will work better than others.

Whey protein is not only one of the highest quality protein powders; it’s the easiest to mix. This is especially true of whey isolate and hydrolyzed whey, which mix into a very thin consistency. These whey protein sources are typically more expensive since they are technically of higher quality.

Casein protein is the thickest protein in terms of mixability. If left in the refrigerator overnight, it may sit like a stone in your shaker bottle. You may have to add liquid (which honestly never works since it just layers on top) in an attempt to get it moving.

Vegan protein can mix very thick as well, especially when other ingredients like peanut butter or a banana are added. Using milk or even almond milk as the base will lead to a thicker consistency than just water.

Protein blends are a mixture of different types of protein. If casein or vegan proteins are part of a blend with whey, then the overall consistency will be more manageable. In this situation, you won’t have to worry about a premixed shake being too concentrated.

Protein blends mix up thicker than a regular whey, but not to the degree of casein. It’s recommended you use a whey protein or a protein blend when making a shake the night before.