Will Casein Protein Before Bed Help Your Gains?
Or this another case of majoring in the minors?
5 min read
By: Dylan Dacosta
“Bruhh, you gotta take Casein before bed because it’s slow releasing and will help you make gainz while you sleep.”
Throughout my time in the gym, I’ve seen this idea tossed around often. It’s an idea that is easy to believe as well since there is a logical explanation to why it works.
Essentially, the idea is that consuming a slow-digesting protein before bed will give you adequate amino acid circulation all night to maximize muscle growth.
An idea like this “makes sense,” which is a part of the issue. There is a common fallacy that just because something “makes sense” means that it’s true. In reality, plenty of oversimplified narratives “make sense,” but they leave out all nuance, and in practical applications, they don’t make a real difference.
So, let’s take a look to see if the casein protein idea fits into this category.
Pre-Bed Casein: Worth Adding to the Nighttime Routine?
Your nighttime routine is precious. One may even say, sacred? So adding in anything better be worth it. So, this idea already has a high bar to climb to see if it’ll stick.
The first thing to get out of the way is to address whether casein protein is, in fact, a “slow digesting protein. As with anything, it depends on what you’re comparing it to. Compared to whey proteins, the casein proteins are slower. That just doesn’t mean much since whey is one of the faster protein sources for digestion speed.
A review paper by Bilsborough et al. in 2005 (1) created a table of approximate speeds of amino acid absorption from differing protein sources. Casein isolate was slower than whey at ~6.1 grams per hour compared to ~8–10 grams per hour.
The issue here was that casein isolate was still one of the faster sources. Raw egg protein was the slowest at ~1.3 grams per hour, and for other isolates, soy protein was slower than casein at ~3.9 grams per hour.
With this in mind, it’s safe to say casein is a slower-digesting protein than whey, but not an actual slow-digesting protein source. Yikes — tough start.
If I were to play “rose-tinted glasses devil's advocate,” I’d say that casein is still slower than whey, so maybe it will yield a positive benefit as a pre-bed intake.
Conveniently, a study by Joy et al. in 2018 (2) compared taking a casein supplement before bed versus during the day in a 10-week resistance training trial
Protein was matched between groups (~2.0 grams per kg of BW), and training was also matched since it was supervised.
Both groups gained similar amounts of muscle with no difference between either group.
This wasn’t whey compared to casein, but this was daytime casein vs. nighttime casein.
This means that if there were a real effect of taking this “slow-digesting” protein source before bed, we would expect to see it here.
OK, So What Should You Do?
I will admit the results above weren’t unsurprising because when it comes to protein, overall intake is the top priority. Then quality, and then timing.
And timing, in this case, is more relevant to distribution than anything. This means that you should try to take in a few high-protein servings during the day as opposed to only one.
Both groups here were doing this. They were training, eating high protein and having multiple servings per day.
As I’ve mentioned before, using the range of 1.6–2.2 grams per kg of body weight per day or 0.7–1.1 grams per pound of body weight per day for those using the imperial system will be a great optimal range to support muscle growth (3).
It’s really hard to justify trying to micromanage every detail of your protein intake if that isn’t covered. And even if that is covered, it’s hard to make a strong case that doing something such as taking in a casein shake before bed is necessary.
Now, if you struggle to get enough protein/calories in, this can be a strategy to try. But the likely reason it will help is because it’ll help you get more protein/calories in. Not because there’s something special about taking a casein supplement before bed.
When it comes to protein supplements, they’re all pretty solid. The one that’s best for you is the one that hits the following:
You like it
It fits your budget
You digest it well
Taking a protein supplement of any kind is honestly a great idea because it’s easy to consume and high in protein.
Considering the two things most of my clients struggle with are eating enough protein and being crunched for time, this makes a supplement a convenient idea.
One thing that can get in the way is getting bogged down thinking you need to consume the “perfect” protein supplement at “the optimal time. You don’t. Just focus on getting it in first and doing so consistently.
You can use this as a reference guide for protein intake.
There is no reason to major in the minors, and thinking you need to optimize pre-bed protein intake is a textbook case of doing so.
Cheers,
Coach Dylan 🍻
References:
1. A Review of Issues of Dietary Protein Intake in Humans
https://journals.humankinetics.com/view/journals/ijsnem/16/2/article-p129.xml
2. Daytime and nighttime casein supplements similarly increase muscle size and strength in response to resistance training earlier in the day: a preliminary investigation
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5952515/
3. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults
https://pubmed.ncbi.nlm.nih.gov/28698222/