Protein Shakes May Not Do Enough for Your Muscles After a Workout

• New research finds evidence that protein shakes may not benefit your muscles recover much after a grueling workout.
• Participants described muscle soreness and reductions in muscle strength and function after going out and having a protein shake.
• The study was small, and experts say more research is needed.

If you reach for a protein shake after a session of heavyweights at the gym, you may not be doing the good you think you are.

Admittedly, weightlifters and also everyday gym-goers have been advised that the solution to successful muscle repair after any weight-intensive session is to take protein shakes.

But a new study from the United Kingdom’s University of Lincoln suggests that protein shakes are no more effective at rebuilding muscle and boosting recovery than high-carbohydrate drinks, like sports drinks.

Indeed, the British researchers say that neither whey protein-based shakes nor milk-based shakes enhanced muscle recovery or eased soreness compared to a carbohydrate only drink.

That refutes a great deal of exercise knowledge, so it’s important to look at the specifics of the study.

What’s the best post-workout recovery drink?

For the study, which was published in the Journal of Human Kinetics, researchers recruited 30 males between the ages of 20 and 30. All participants had at least a year’s experience with resistance training before the study.

The 30 participants were divided into three groups. Each group was assigned to consume either a whey hydrolysate drink, a milk drink, or a flavored carbohydrate drink after a prescribed intensive resistance training session.

After the workout, the participants were re-tested and asked to rate their levels of muscle soreness on a scale from zero (“no muscle soreness”) to 200 (“muscle soreness as bad as it could be”). The researchers also asked the participants to complete a series of strength and power assessments, including throwing a medicine ball while seated and jumping as high as possible from a squatted position.

At the start of the study, any participants rated their muscle soreness in 19 and 26, or quite low. Then, they reassessed those measurements 24 and 48 hours after the weight-lifting session. All participants rated their soreness above 90, which is quite high.

What’s more, in the physical assessments, the participants showed reductions in muscle power and function.

However, there was no difference in recovery response and soreness scores between the three different groups. That means, the study’s authors concluded, that there is no additional interest in consuming protein shakes or juices for the sake of muscle return.

“While proteins and carbs are necessary for the effective repair of muscle tissues following intensive strength training, our research proposes that varying the form of protein directly following training does not greatly influence the recovery answer or reduce muscle pain,” lead author Thomas Gee, PhD, program leader of strength and conditioning in sport at the University of Lincoln, said in a statement. “We would hypothesize that well equivalent daily nutrition exercises would influence recovery from delayed onset muscle soreness to a higher extent.”

Flaws in the study

These results seem surprising, precisely because they refute decades’ worth of common workout wisdom. Previous researchTrusted Source has shown that protein can ease soreness, speed up recovery, and help repair the muscles that are torn during weightlifting. Plus, one study of nearly 50 studies found that protein supplementation very enhanced muscle strength and size during resistance training.

Therefore, it’s important to point out a few issues with this study that you should consider when weighing whether to shake up a drink after leg day.

First, the study is quite small it had just 30 participants. Many small-scale studies are reported on — and many of the studies in this field of research are likewise small so the caveat with these should always be that larger, more expansive studies are needed to verify the results.

Second, despite using three different beverages, the researchers used no control. In other words, they didn’t have a group that consumed just water. With this, they might have been able to determine if nutrient-rich drinks have any value at all in recovery.

“Recovery and repair of muscles do not just come down to only protein,” says Melissa Morris, EdD, a professor of applied kinesiology at the University of Tampa. “You necessity also consider the type of exercise, rest, hydration, and overall nutrition, which gives it complicated to link just protein to repair and recovery.”

Indeed, muscle repair and rebuilding requires both protein and carbs. Protein helps restore the muscle and build strength; carbohydrates refurbish the glycogen levels. Glycogen is a substance that’s stored in the muscles and used by the body for energy.

In short-term recovery say, 24 to 48 hours after a workout it’s possible the mix of nutrients doesn’t matter as much. But in a long time, having high-quality protein with carbohydrates may win out over carbs or protein only. Additional research would be needed to verify that.

“In my 15 years of coaching experience, what seems to matter most for recreational athletes, or regular people, is the total amount and quality of protein eaten over the day, rather than the precise time of the protein intake,” says sports nutritionist Jonathan Wong, CEO, and founder of Genesis Gym.

The bottom line

Perhaps this study points out that protein and carbohydrates in isolation aren’t the solutions. The next study in this area may benefit from comparing drinks with a combination of protein and carbohydrates to ones with one macronutrient alone.

“The purpose isn’t to just think about protein,” says Rachel Fine, MS, RD, owner of To The Pointe Nutrition. “To best optimize post-workout muscle repair, a mix of carbs and protein is important.”