The 5 best casein protein powders of 2024, according to nutrition experts 

Why we like Legion Casein+ as best natural

Legion Casein+ stands out as the best natural casein protein powder due to its clean, well-rounded formulation that supports optimal protein intake. Each scoop provides 24-26 grams of micellar casein protein and 50-60% of your daily calcium needs with no added sugars, two to five grams of carbohydrates, and 110-140 calories, depending on which flavor you choose. Its low carbohydrate content, ranging from two to five grams per serving, makes it an excellent choice for those mindful of their macros.

Experts often prefer micellar casein since it maintains the natural structure of casein protein, which coagulates in the stomach and slows digestion. Other forms of casein, like casein hydrolysates, are processed into smaller molecules, losing some slow-digesting benefits. While micellar casein is more popular, there’s no clear proof that one type is better than the other. (3, 4)

Although Legion’s nutrition profile is comparable to that of the other products on our list, it stands out for a few reasons. First, it uses only naturally derived flavors, sweeteners, and food coloring. It’s also soy-free, gluten-free, and non-GMO project verified, meeting many people’s dietary needs. 

Legion goes the extra mile to pursue best practices in sourcing. Their casein is sourced from Truly Grass Fed ®, a brand of Irish dairy products committed to sustainability and animal welfare. According to their website, they guarantee that their cows live on pasture and eat grass 95% of the year. None of their products contain hormones or antibiotics. 

Finally, for safety and integrity, Legion sends its products for third-party testing to check for ingredient potency and harmful contaminants. They also avoid making sensational claims on their website, providing realistic information about what this product can help with. Best of all, they stand behind their products with a 100%, no-questions-asked money-back guarantee. They don’t even require you to send the product back to them, so there’s very little risk in trying it.  

Related: The best clean protein powders

What to consider

Legion Casein+ has a few downsides to consider. At $2 per serving, it costs more than most of the other brands on our list. The good news is that their subscription program discounts their products to $1.80 per serving, which is more in line with the average cost of casein protein powder. 

You should also be aware that Legion products contain stevia as well as sugar alcohol, which can cause digestive symptoms in some people. (5) 

Also, our testers noted that Legion Casein+ works best when mixed with milk rather than water. When mixed with water, it leaves an unappealing chalky taste that will coat the inside of your mouth. Also, if it sits too long, the mixture will start to separate.

For more information, check out our full Legion protein review.

What customers are saying

1,094 reviewers on Amazon have rated Legion Casein+, and overall, customers are happy with the taste and quality of the casein powder.

Jeff D adds, “What I really like is that the marketing does match what their products are. They don’t have as many random ingredients with questionable data behind them and are more simple. Some people look at that as a negative, but I would rather use quality products that are intentionally designed than the kitchen sink ones.”

Among the few complaints, customers recommend handling the product carefully, as the fine powder can easily make a mess. And, if you don’t like stevia, you won’t like this product. 

“This may not apply to anyone else, but I, personally, can’t handle Stevia as a sweetener,” James writes. “To me, it tastes just like aspartame—a very chemical-like aftertaste. I’m sure this is just a matter of taste (or perhaps how I’ve trained my taste buds), but I wasn’t a huge fan of this stuff in the amount necessary to make a shake. Just too much Stevia flavor for me.”

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Why we like Transparent Labs 100% Grass Fed Casein as the best-tasting casein protein powder

Transparent Labs is known for creating quality supplements with straightforward formulations, and their casein protein powder is no exception. Transparent Lab’s casein gets extra recognition for its great taste. The only available flavor is chocolate, but our testers raved about it. They love its rich chocolate taste with a subtle hint of saltiness from the Himalayan rock salt. 

A popular recommendation is to use this powder to make chocolate pudding. To do so, simply add less water than instructed. One tester compared it to a classic Jell-O pudding cup, highlighting its smooth texture and authentic chocolate flavor. 

Beyond its flavoring, it offers many other perks. One-scoop serving delivers a substantial 25 grams of 100% grass-fed micellar casein and 60% of the daily value of calcium with no added sugars, only four grams of carbohydrates, and 120 calories. 

This casein protein powder’s simple ingredient list is free of soy, gluten, artificial sweeteners, and dyes. Plus, sourcing from grass-fed cows may help boost this product’s nutrient content while limiting exposure to hormones and antibiotics, according to some data. (6) Additionally, this supplement is Informed Choice Certified, meaning a third party tests it for harmful and banned substances.

To discover more insights on this brand, check out our full Transparent Labs protein review.

What to consider

With Transparent Labs 100% Grass Fed Casein, it’s worth noting that this product has the highest sodium content on our list, with 300 milligrams per scoop, slightly over 10% of the daily value. Note that it does use stevia, which some customers may wish to avoid.

At $2 per serving, Transparent Labs 100% Grass Fed Casein is our list’s second most expensive product. However, if you crave a chocolate treat, it just may be worth it.

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Why we like Nutricost as best casein for muscle gain 

Nutricost provides 24 grams of micellar protein in each serving for about half the cost of comparable products. This affordability is a plus for people trying to build muscle mass who may need more than one serving daily to meet their protein goals. 

Research suggests that to gain muscle strength, you need about double the recommended daily allowance (RDA) for protein intake, approximately 1.6 grams per kilogram of body weight. (7, 8) To maintain these gains, casein is often recommended as a bedtime supplement because its slow digestion can help support muscle growth and recovery overnight. However, these benefits are only seen with doses of at least 40 grams taken post-exercise and about 30 minutes before sleep. (1) Nutricost can help you hit these high-protein targets without breaking the bank. 

Nutricost’s vanilla casein is also versatile. It works well in chocolate peanut butter protein waffles and high-protein cookie dough, meaning you don’t have to drink multiple protein shakes to hit your protein targets. (You can find these recipes and more on Nutricost’s website.) Plus, its lean nutrition profile allows you to create recipes that are dialed in to your specific nutrient parameters. One serving contains just 110 calories, one gram of carbohydrates, 190 milligrams of sodium, and 45% of the daily value of calcium.

Another perk Nutricost offers is convenience. The Nutricost casein comes in a five-pound tub with 71 servings. If you take two servings a day, this will last you well over a month.

Related: The best low-carb protein powders

What to consider

It’s worth noting that this product does contains artificial flavors and sucralose, which some people may wish to avoid. On the bright side, it’s third-party tested, so you can rest easy knowing it’s monitored for harmful substances like heavy metals and contaminants.

To learn more, check out our full Nutricost protein powder review or our complete guide on the best protein powders for muscle gain.

What customers are saying

Nutricost Vanilla Casein has garnered over 1,800 customer reviews on Amazon. Most appreciate its versatility and affordability and think the flavor is decent. 

Another customer,  Tom F., describes it as a “good product” at a “great value.” 

However, other reviewers think it’s just okay due to the gritty texture. Nathan S. writes, “It’s not the best tasting, but it’s great for long-digesting protein.” 

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Why we like Promix Unflavored Micellar Casein Protein Powder as the best unflavored casein

Promix offers a great unflavored casein protein powder because of its minimal ingredients, versatility, and affordability. Each two-scoop serving provides 25 grams of grass-fed micellar casein with no artificial sweeteners or additives, making it a good fit for people seeking a simple and versatile casein protein powder.

With Promix’s unflavored casein protein powder, you can create recipes with flavors you enjoy instead of being stuck with chalky, artificially sweetened protein powder. Our favorite ways to use unflavored casein powder include adding it to pancake batter, mixing it into oatmeal with cinnamon, or blending it with vanilla almond milk, bananas, and ice. Promix’s formula reportedly works well with these types of recipes, adding a creamy texture without an artificial aftertaste.

Still, a major advantage of Promix’s unflavored casein is its straightforward formula, containing only two ingredients: micellar casein and sunflower lecithin. This simplicity results in an impressive nutritional profile with just 105 calories, 45 milligrams of sodium (the lowest on our list), no sugar, and 63% of the daily value of calcium per serving.

Promix’s pared-down formula also keeps it affordable; at $1.14 per serving, it’s one of the best values available. Additionally, it comes in a five-pound package that lasts over two months, offering extra convenience and cost savings.

Despite its reasonable price, the company commits to ensuring ingredient quality. This casein is ultra-filtered to remove lactose for easy digestion, and each batch undergoes third-party testing.

Upon testing, we learned Promix doesn’t dissolve well in plain milk or water. Instead, it leaves a gritty texture and an unpleasant aftertaste. The same issue occurs when mixed with plain liquid in a shaker bottle.

What to consider

Upon testing, we learned Promix doesn’t dissolve well in plain milk or water. Instead, it leaves a gritty texture and an unpleasant aftertaste. The same issue occurs when mixed with plain liquid in a shaker bottle.

What customers are saying

Promix Casein has received 610 customer reviews on Amazon. Customers praise this product for its quality and simplicity.

Ddfusc, another verified customer, feels similarly, writing, “I wanted a casein protein without any artificial sweeteners (aspartame, sucralose…). I didn’t know if I would like something that has no flavor but when I mixed this (very easy to mix, no clumps) with almond milk it just tastes like regular milk which is great. In smoothies I’ll use different frozen berries and it is awesome. Also doesn’t have any weird chemical aftertaste like you get with other proteins.”

Most negative reviews complain of a gritty texture, undissolved clumps, and chalky aftertaste when shaken or stirred into plain liquid.  

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Why we like Optimum Nutrition Platinum Rebuild as best whey and casein

Optimum Nutrition’s Platinum Rebuild provides 24 grams of protein from casein and whey sources, plus other ingredients to help maximize muscle performance and recovery. When it comes to optimizing muscle gains, getting enough total protein is the most important factor. However, different protein sources play different roles in muscle health, and you may be able to fine-tune your results by leveraging the advantages of each. (9)

“This product contains whey and casein, the two types of protein found in milk. Both are complete proteins, meaning they contain all of the essential amino acids needed to support muscle growth; however, they act differently due to how they are digested,” says Mohr. 

Whey is considered a “fast protein” because it digests quickly. This makes it best to consume after a workout, as it rapidly replenishes muscle protein stores, aiding muscle growth. Conversely, casein digests slowly, gradually releasing amino acids into circulation. This helps prevent muscle breakdown. By combining these protein sources, Optimum Nutrition gives you the best of both worlds. (10)

Two additional ingredients are included in this product to help enhance your results: creatine monohydrate and L-glutamine. 

Creatine is an amino acid shown to help improve muscle strength and performance. According to the International Society of Sports Nutrition (ISSN), three to five grams of creatine are needed daily to see benefits. Optimum Nutrition provides three grams in each serving. (11)

L-glutamine is another amino acid thought to improve muscle recovery, but so far, research shows minimal effects. (12) Nonetheless, each serving of Optimum Nutrition’s formula contains three grams of this amino acid. 

 A full-size tub only provides 20 servings, so be prepared to order frequently. Two flavors are available: dark chocolate and vanilla buttercream.

Check out our full Optimum Nutrition protein review for more information.

What to consider

If sustainability and clean labels are a priority for you, this may not be the best option. The ingredient list includes artificial flavors, gums, sucralose, and acesulfame-K, and there’s no indication that it’s sourced from sustainable or grass-fed sources.

At $3 per serving, Optimum Nutrition Platinum Rebuild is the most expensive on our list. However, Optimum Nutrition is highly regarded by athletes, especially for its Gold Standard whey protein, which is often considered one of the best.

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