Endurox R4 made by PacificHealth Labs is a sports recovery drink that aims to help replenish glycogen stores, reduce exercise induced muscle damage, and induce a greater insulin response. It's based on what Endurox calls the 4 to 1 ratio of carbs and protein science that leads to better hydration, increased endurance, and improved post exercise muscle recovery compared to carbohydrate drinks alone - namely, for every gram of protein, there are 4 grams of carbs.
These claims are backed up with numerous scientific studies that demonstrate the benefits of a protein / carbohydrate drink compared to pure carbohydrate drinks alone. There are studies done not only on protein-carbohydrate mixes, but also done on Endurox itself to compare its efficacy versus a leading carbohydrate drink. We'll get to these studies in a bit. First, a look at the ingredients of Endurox R4.
Endurox R4 Ingredients
As previously mentioned, the main ingredients in Endurox R4 are protein and carbohydrates in a 4 to 1 ratio. See below:
Serving Size: 2 rounded scoops (75g)
Servings Per Container: 14
Amount Per Serving
Calories 270 Calories from Fat 10
% Daily Value*
Total Fat 1g 1%*
Saturated Fat 0g 0%
Cholesterol 10mg 3%
Sodium 210 mg 9%
Potassium 120mg 3%
Total Carbohydrate 52g 17%*
Dietary Fiber 0g 0%
Sugars 40g **
Magnesium 60% Vitamin C 780%
Vitamin E 1330% Calcium 10%
L-Glutamine 420mg **
*Percent Daily Values are based on a 2,000 calorie diet.
**Daily values not established.
INGREDIENTS: Dextrose, whey protein concentrate, complex carbohydrates, fructose, sucrose, citric acid, magnesium carbonate, natural flavor, ascorbic acid, sodium chloride, L-glutamine, vitamin E acetate, lecithin, monopotassium phosphate, FD&C red 40.
As you can see, each serving of Endurox R4 contains 13g of protein along with 52g of carbohydrates, a precise 4 to 1 ratio. The suggest use is immediately after exercise. I would suggest taking this as the bottle instructions, and plus another scoop or two of whey protein afterwards. 13g of protein per serving is a little on the light side, and I generally take another shake with 2 scoops of whey to get a little more whey protein post workout.
Pacific Health Labs Endurox R4 Studies
There are numerous studies showing the benefits of ingesting a protein and carbohydrate mix compared to a carbohydrate drink alone. Below are several studies that you may find interesting, and one of them was done using Endurox R4, and comparing it to a leading carbohydrate drink.
Carbohydrate-protein complex increases the rate of muscle glycogen storage after exercise K. M. Zawadzki, B. B. Yaspelkis 3rd and J. L. Ivy Department of Kinesiology, University of Texas, Austin 78712.
This study compared carbohydrate, protein, and carbohydrate-protein supplements to determine their effects on muscle glycogen storage during recovery from prolonged exercise. 9 male subjects cycled for 2 hours on 3 occasions to deplete muscle glycogen stores. Immediately after each 2 hour session, they were fed with either a 112g carbohydrate solution, a 40g protein solution, or a mix of 112g and 40g protein solution.
Blood samples were taken before and after exercise, and throughout recovery. They found that the carb/protein group had significantly greater plasma insulin response, and the rate of muscle glycogen storage of the carb/protein group was significantly faster than both the carbohydrate group and the protein group. This lead the researchers to conclude that consuming a protein and carbohydrate mix can enhance post exercise muscle glycogen storage.
Effects of Recovery Beverages on Glycogen
Restoration and Endurance Exercise Performance MICHAEL B. WILLIAMS,1 PETER B. RAVEN,1 DONOVAN L. FOGT,2 AND
JOHN L. IVY Cardiovascular Research Institute, University of North Texas, Health Science Center at Fort Worth, Texas
76107; 2Exercise Physiology and Metabolism Laboratory, Department of Kinesiology and Health Education,
University of Texas at Austin, Texas 78712.
This study compared a carbohydrate-protein drink (Endurox R4) to a popular leading carbohydrate drink (Gatorade) after glycogen depleting exercise. Two separate studies were conducted to compare the efficacy of these two sports drinks. The first study was conducted at the University of North Texas
Health Science Center, Forth Worth, TX, and study 2
was conducted at the University of Texas, Austin, TX. Because the two studies were conducted in different locations, the subjects used were different as well.
The researchers found that consuming the carbohydrate-protein beverage resulted in a 55% greater time to exhaustion during subsequent exercise compared to the pure carbohydrate beverage. They attributed the faster recovery to the increased rate of muscle glycogen storage by consuming the carbohydrate-protein beverage.
In the second study, they found that that carbohydrate-protein drink group had 17% better plasma glucose response, 92% greater insulin response, and 128% greater storage of muscle glycogen. Their findings
indicate that the rate of recovery is coupled with the
rate of muscle glycogen replenishment and that a protein-carbohydrate drink provides better recovery than the carbohydrate drink alone.
Early post exercise muscle glycogen recovery is enhanced with a carbohydrate-protein supplement John L. Ivy1, Harold W. Goforth Jr., Bruce M. Damon, Thomas R. McCauley, Edward C. Parsons, and Thomas B. Price Exercise Physiology and Metabolism Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas 78712; Department of Biology, Point Loma Nazarene University, San Diego, California; and 3 Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut 06510
This is another study that tested the hypothesis that carbohydrate-protein supplements are more effective in replenishing muscle glycogen stores after exercise compared to a carbohydrate supplement alone. Muscle glycogen stores were depleted in the subjects after an intense 2.5 hour cycling session. They received either a carb-protein drink (80g carb and 28g protein), a high carb drink (108g), or a lower carb drink (80g).
After 4hours of recovery, muscle glycogen was significantly greater in the carbohydrate-protein group compared to both the low and high carbohydrate groups. Their results indicate that taking a protein and carbohydrate mix for exercise recovery is more effective for rapid replenishment of muscle glycogen compared to a plain carbohydrate supplement alone.
Endurox R4 Review Conclusion
It should come as no surprise that protein and carbohydrate mix does a much better job at replenishing glycogen stores than a pure carbohydrate supplement alone, and the studies we highlighted above clearly agrees as much. So if you're not already taking a protein / carbohydrate mix post exercise, consider doing so to help replenish glycogen stores and speed up your recovery process.
Taste wise, I give Endurox R4 two thumbs up. Endurox comes in several flavors including chocolate, vanilla, orange, lemon lime, and fruit punch. I've tried both orange and lemon lime, and they both tasted excellent. They also mix easily with a shaker with no clumps.
1. Journal of Applied Physiology, Vol 72, Issue 5 1854-1859,1992
2. Journal of Strength and Conditioning Research, 2003, 17(1), 12–19
3. J Appl Physiol 93: 1337-1344, 2002. First published July 12, 2002