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Optimum Nutrition 100% Casein vs. BSN Syntha 6

What is Optimum Nutrition 100% Casein?

Sure, whey protein may be what you'll find in most kitchens but only those who are serious about supplementing their muscle gains go the extra mile with casein protein. Optimum Nutrition 100% Casein is an elite quality protein supplement packed with 24 grams per serving that can support muscle mass and recovery.



  • Provides 24 grams of pure micellar casein
  • Slowest digesting protein that supports a variety of fitness goals
  • Claims to deliver eight hours' worth of amino acids, making it the ideal recovery supplement to avoid catabolism (protein breakdown)
  • Low fat and low carb


Why You Should Use Optimum Nutrition 100% Casein

Casein protein is not your standard whey protein supplement. The two are very different. Sure, both supply usable amino acids to muscle tissue but casein breaks down at a much slower rate. With an extended release of up to eight hours of amino acids, casein protein ensures an anabolic environment.


This makes it ideal for those pursuing growth and recovery-related goals. For example, if you want to build muscle mass or encourage a faster rate of recovery, Optimum Nutrition 100% Casein would be the go-to supplement.


What sets Optimum Nutrition 100% Casein apart from BSN Syntha 6 is the caloric, protein, and fat content. Optimum Nutrition provides a lower calorie protein supplement that is only protein. Syntha 6 delivers a protein and healthy fatty acid blend, which means more calories. The extra calories could help or hurt your fitness goals, depending on what they are.


Things to Watch Out for With Optimum Nutrition 100% Casein

Optimum Nutrition supplies a gram of fibre via polydextrose, which is a synthetic form of fibre, not to be confused with whole and natural forms such as wheat bran or oats. With only a gram of fibre per serving, this shouldn't pose a risk or any issues especially if you've used major brand supplements in the past. BSN Syntha 6 also contains polydextrose, providing 5 grams of fibre per serving. If you have sensitivities with digestion and artificial additives, Optimum Nutrition may be the supplement that wins out.



What is BSN Syntha 6?

BSN Syntha 6 is a great tasting protein blend that provides 22 grams of a variety of the most effective protein sources including concentrate, isolate, and casein. This means getting an immediate shot of amino acids and an extended release throughout the day. Used as directed, Syntha 6 can help to support lean muscle building, weight management, and performance enhancement.



  • 22 grams of protein from a unique blend
  • Reports 10 grams of amino acids per serving – Optimum Nutrition provides 9 grams per serving
  • Provides fatty acid blend, fibre, and digestive enzymes
  • Higher in calories than O.N. Casein, which may make it ideal for muscle mass gains


Why You Should Use BSN Syntha 6

Syntha 6 utilizes a protein blend of whey protein concentrate, whey protein isolate, calcium caseinate, micellar casein, milk protein isolate, egg albumin, and glutamine peptides. Depending on your fitness goals, protein blends may be the ideal option because they supply amino acids sooner than casein but also provide an extended release over the course of a few hours.


Like Optimum Nutrition Casein, BSN Syntha 6 is also an effective muscle builder and recovery booster. However, unlike the casein protein, Syntha 6 provides a higher number of calories along with fat and fibre. This means a slower rate of protein digestion – although not as slow as casein. What's more, if you are trying to stay within a daily caloric limit, Syntha 6 may not be an ideal meal replacement supplement.


We recommend Syntha 6 for goals involving muscle building, performance enhancement, and strength building. Those seeking weight loss may prefer the lower calorie Optimum Nutrition 100% Casein with only 120 calories and 24 grams of protein per serving.


Things to Watch Out for With BSN Syntha 6

Aside from the polydextrose mentioned above, the only other issue that we see with Syntha 6 would be the inclusion of artificial sweeteners and additives. Optimum Nutrition 100% Casein also contains sweeteners but only Syntha 6 provides digestive enzymes that may help you avoid any gas or bloating.


Which Supplement Should You Use?

Neither supplement would be an ideal post-workout protein due to the slower digestion speed; however, both are excellent depending on what you want to achieve.


Looking to build muscle, perform better, recovery faster with no regard for caloric intake? Try BSN Syntha 6.


Do you want to increase your daily consumption of protein while keeping in mind your low-calorie diet? Optimum Nutrition 100% Casein is your answer.


Trying both would also give you an opportunity to see which brand your body responds the best to and the progress of your results on each supplement.



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