Casein vs Whey Protein: What’s the Difference & is One Better Than the Other For Weight Loss?

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The casein vs whey protein debate has been going on for years. While some swear by their post-workout whey shake, others think it's overrated, and opt for casein to cover their protein needs.

But which is better? And do you need both?

We answer these question and more in our straight-talking comparison of two of, if not the most popular protein shakes on the market.

What Does Whey Do And Who Should Take It?

Image of a scoop of chocolate whey protein powder

Being naturally high in leucine and BCAAs, whey protein is a supplement that stimulates the muscle growth signal more rapidly than any other protein. Whey is commonly used after resistance training by those looking for the quickest possible kickstart in recovery because it contains more bcaas than casein.

It typically has fewer grams of fats and carbs than casein and is usually the protein powder of choice for those seeking to maximize their weight loss efforts.

Although there are 3 types of whey — concentrates, isolates, and hydrolysates — isolates and hydrolysates are most commonly used for weight loss due to being lower in calories. Being higher in protein than concentrates, they're also used by bodybuilders who want the purest source of protein available to nourish their muscles.

Who Should Take Whey?

  • Those on low-calorie diets
  • Bodybuilders
  • People seeking a better mixing protein shake
  • Budget supplement users

What Is Casein For And Who Should Use It?

Image of chocolate and vanilla protein shakes

Despite having less BCAAs than its counterpart, casein is significantly higher in essential minerals like calcium, typically containing around 40% of the RDI, based on a 2000 calorie intake.

Containing all of the 9 essential amino acids, but being naturally slower-digesting than whey, the initial spike in muscle growth signaling isn't as sharp. However, protein synthesis is much more prolonged, and casein may well be equally as effective as whey for muscle growth, and significantly better in some situations, such as before sleep or after late night workouts.

More on protein timing later.

An intriguing 2011 research study found casein to increase feelings of fullness and hunger satisfaction more than whey. The same researchers then gave people either casein, whey, or pea protein 30 minutes before an ‘all you can eat' style buffet meal.

The lucky people who got a casein shake ate less food than those who were lumped with whey, indicating that casein may be better for weight loss. But wait, there's more...

Casein vs Whey For Weight Loss: Does It Matter?

So, is casein protein better than whey for losing weight?

Probably not, at least not to any significant degree.

Although credible research finds casein to decrease food intake to a more significant extent than whey, it seems like there is little difference over the long term.

What Do The Experts Say About Losing Fat?

Interestingly, a group of researchers found that, for a group of overweight and obese participants, casein was significantly worse than whey for increasing feelings of satiety and fullness. Fullness is essential for dropping fat because the less satisfying you find your protein shake, the more food you're likely to consume elsewhere.

Another nail in the coffin for casein's reign as ‘weight loss protein' is the fact that over 12 weeks, the same overweight and obese subjects lost no extra weight, and consumed no fewer calories, than those who drank whey.

Being generally better value, and boasting much better mixability, there's little reason to use casein rather whey for weight loss. Unless, of course, you want to grow muscle at the same time as losing fat, in which case you could drink a casein shake before bed.

More on how to do that in just a moment.

Image of a slim woman measuring her waist

Which is Best For Muscle Growth?

When it comes to a protein of any kind, by far the most significant determinant of how muscle you'll grow, is your total protein intake, you can take the most anabolic powder in the entire supplement land, but if your overall protein intake is sub-par, your results will be, too.

The fix?

Be as consistent in consuming [quality] protein every day, as you are in turning up to the gym week in, week out. I know it makes you feel hardcore like you're Mr. Olympia, but there is no need to eat an absurd amount either. It won't make you grow anymore, and if anything, you will turn into a walking fart machine.

Keep your intake at least 1.8g/kg or 0.82g/ lb and let your training, diet, sleep, and genetics, take care of the rest.

Ok, But Which Should I Take To Grow?

Have you just finished a hard training session at the gym? Yeah?

Then go with whey today.

Is it getting later in the day at your place in the world?

Then take casein, not whey. It keeps you more anabolic while you sleep, and you can make excellent casein pudding with it.

Image of a bodybuilder drinking his post-workout shake

Casein Or Whey For Bulking Diets?

Here's a quick answer for you, because when you're bulking, who wants to spend time reading the internet when you could be making your next meal?

If you're bulking correctly, that is, having an intense enough training stimulus, an adequate diet with a surplus, and restful sleep, it doesn't matter which kind of protein you take.

That said, if I were bulking on a budget, I'd go with whey over casein. Why?

It's usually cheaper than casein, it mixes better than casein, and it's probably a tiny bit more effective at every other period, other than before bed. And as pre-bed protein is so vital for our gains, I can easily make a convincing argument for buying both.

The Hierarchy Of protein While Bulking

  • Total Protein intake
  • Post-workout whey
  • Pre-bed protein
  • Spreading protein servings out through the day

Time Of Use

Before Bed

Unless you only sleep for a few hours each night, which is a terrible idea for health and muscle growth, drink casein before bed to maximize overnight recovery.

But if you can't afford casein, go ahead and mix a scoop of whey with milk instead. Being naturally 80%-90% casein, adding milk to your nighttime whey protein shake is a neat little trick to get the benefits of casein, without paying top dollar for a full tub of powder.

After A Workout

Image of a woman looking tired in the locker room after a workout

Unlike before bedtime, you want a fast-acting protein source after training, to kickstart growth and recovery as quickly as possible. With whey being such a popular supplement, most people take it intuitively after exercise, but if you don't, then you may well benefit from doing so, especially if you're concerned with muscle growth.

You can read more about which supplements are right for you, by checking out our guide.

The Verdict

Overall, either supplement can help you grow slabs of muscle, and shed pounds of fat, if you take them consistently, and understand that they're not a magic cure-all.

While many consider whey as some kind of super supplement for growth, casein is likely equally as good over the long-term, and significantly more effective at bedtime.

However, those who are on a budget should stick with whey because it mixes better than casein, generally tastes nicer, and it a tried and tested post-workout supplement, fit for any type goal and person.

I hope you enjoyed our casein vs whey protein comparison. Hopefully, you can decide which kind to go for next time.

Protein Powder


Our Rating


#1 Naked Whey





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#2 Combat Powder





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The Budget Choice

#3 Gold Standard Whey





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The Best all-rounder

#4 BSN Syntha-6





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The Best Tasting

#5 Isopure Zero Carb





Best For

Weight Loss

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Jonathan Abbott
Jonathan Abbott
Jonathan is a long time fitness enthusiast who specializes in helping others reach their goals faster with the most up to date sports science. When he's not working, you'll find him challanging his body with heavy squats and deadlifts.

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