The protein powder supplement market is big business. Popular in the world of sport where muscle growth is prized, the marketplace is dominated by glossy pictures of cut models and an ever-expanding list of claims for how these supplements will pack on the muscle. So, do the gym bros have it right when they say that you need these supplements if you’re serious about the gainz? Or could plain old boring ‘food’ do the same job? In this post, I dig deeper into the world of protein and muscle growth and see what the research has to say about protein supplements.
The protein and amino acid supplement market is big business. Bars, shakes, giant tubs of powder and specialist amino acid supplements dominate supplement shelves. All in the name of bigger and stronger muscles.
No athlete would dispute that more muscle is an advantage in sports. Dietary protein is the source of the amino acid building blocks needed for new muscle growth and repair. With a strength training stimulus and adequate dietary protein, new muscle protein synthesis is the result. But is there a role for extra protein through the use of supplements to get even more muscle growth and strength gains?
Is more protein better?
To answer this question, let’s first explore how much protein sportspeople need. Consensus position statements such as those produced by the American College of Sports Medicine give the range of 1.2 grams to 1.7 grams of protein per kilogram of body weight. The Australian Institute of Sport also gives a similar range of 1.2 to 1.6 grams of protein per kilogram of body weight.
Higher recommendation ranges can sometimes be seen of 1.6 to 2.4 grams per kilogram of body weight, but this is for athletes who are on weight loss programs and are trying to add or maintain muscle bulk while losing weight at the same time.
The top end range of 1.7 grams per kilogram of body weight though is for elite endurance athletes, athletes in strength and power sports and those in the early stages of a strength training phase as they ramp up their gym training. The ‘recreational athlete’, which describes the vast majority of active sportspeople, only needs to aim for the bottom end of the range which is around 1.2 grams per kilogram. Which as a fun fact, is the average amount of protein a typical Australian adult eats each day just from their regular diet – no protein supplements required.
Sportspeople are more focused on protein in their diet than the average person. So just how much protein do you think they would get from their normal diet on average? Dietary surveys show the normal diet of strength-based athletes provides around two grams of protein per kilogram of body weight per day. And that’s before using any protein powders.
But is there much benefit to eating protein above the upper limit range? If there is, it is hard to see a difference in clinical trials. This 2017 meta-analysis of 49 studies looking at protein supplementation in resistance exercise training found that as protein intake goes up, so too does muscle strength and size. But this maxed out at 1.6 grams per kilogram of body weight.
The case for protein supplements
Before you think there’s ‘nothing to see here’ when it comes to protein supplements, they can’t be dismissed completely. There are circumstances where supplementation is an appropriate and convenient option for athletes.
When travelling, or during an intense training schedule where it is difficult to access, prepare and consume adequate food as proper meals can all be situations where it is convenient and practical to reach for a ready-to-drink protein supplement.
And then there is the case of athletes trying to drop weight on energy-restricted diets. They may find it harder to meet protein requirements so a protein supplement could be of use. Under energy-restricted conditions, a greater proportion of amino acids are used for energy production, resulting in fewer amino acids available for muscle growth so the idea to supplement with protein has merit.
While the research in this area is not as mature, for athletes trying to drop weight and wanting to maintain and promote lean body mass, protein goals of well into the 2 grams per kilogram of body weight range could be considered. At these sorts of numbers, protein supplements enter the game.
Getting your timing right
Moving on from daily protein requirements, is there merit to the notion of optimising muscle growth through the timing of protein consumption?
Optimal muscle growth and recovery is more than about meeting daily protein needs. And this is where the concept of protein timing around exercise has some credence. Each time protein is eaten, there is a small spike in muscle synthesis with a ‘dose’ of about 20 to 25 grams of high-quality protein sufficient to stimulate muscle protein synthesis following resistance exercise.
Having these protein ‘doses’ spread throughout the day can help to maximise exercise-induced muscular growth and aid the repair of damaged tissue. Eating quantities of protein above this 20 to 25 gram range in one sitting offers only a limited additional benefit with a very minor 10 percent further protein synthesis when the amount is doubled to 40 grams.
Despite the common recommendation to consume protein as soon as possible post-exercise, evidence-based support for this practice is lacking. That doesn’t mean that it shouldn’t be done. Only that it shouldn’t be treated as Gospel despite what the bros at the gym may tell you.
How long the mythical ‘post-exercise muscle anabolism’ window remains open for is still hotly debated. But it likely exists for several hours. So, fear not gym goers, your muscle gains aren’t going to evaporate because you didn’t chug down your protein shake within five minutes of your last set of bench presses.
There was a nice review paper on the topic of protein timing published in 2013 which is well worth reading if you want to know more about this area. Combining all the protein timing research leads to the conclusion that the body likely responds best to regular small ‘doses’ of protein throughout the day. I like to call this new muscle growth optimisation protocol “regular meals and snacks with a focus on higher-protein foods”. Others may just call it eating.
The AIS frames this advice by encouraging athletes to include a small serving of protein-rich foods on 3 to 5 eating occasions each day. Targets of 0.3 to 0.4 grams of protein per kilogram of body weight per meal or snack would equate to 15 to 30 grams of protein at each meal or snack.
Wheying in on protein form
So that’s dose and timing covered off. What about the form of protein that is best to consume? Not all protein sources are created equal due to their amino acid composition and how quickly they are digested and absorbed. In the field of sports nutrition research, it’s dairy proteins that receive much of the attention.
The two main proteins in dairy are casein and whey. They are digested and absorbed at different rates, with whey getting into the bloodstream faster than casein. Most protein supplements are based on whey, but that’s more due to convenience because of its ready availability: it’s a waste product from cheese manufacturing after all.
Whey protein is of particular interest because it appears to have a stronger anabolic effect on muscle growth. That’s because of its higher content of a specific essential amino acid called leucine. Leucine is a branched-chain amino acid that has attracted interest for its ability to build muscles and activate a protein known as mTOR, which triggers muscle protein synthesis.
Plant proteins power muscle gains too
With a growing interest in vegetarian diets, soy protein is also a popular option. Soy is a high-biological-value protein that is rapidly digested. It comes as both a soy concentrate and soy isolate. While the balance of research indicates that whey protein may have a small edge for muscle building, some studies have found soy foods to be just as effective as whey protein in terms of their ability to promote gains in lean muscle mass.
One study, for example, found daily supplementation of 50 grams of soy, whey, or a soy-whey protein blend in 20 male athletes engaging in a weight-training program all resulted in similar increases in lean body mass and did not negatively affect testosterone or estrogen levels.
Then there was this systematic review published in 2023 looking at soy protein in muscle adaptations. Soy protein could be seen to increase lean mass during resistance training similar to whey protein. This shows that soy protein can be as effective as whey protein in building lean muscle mass especially if the leucine content of the diet is matched.
Pea protein is another protein powder that is growing in popularity among vegetarians and people with allergies or sensitivities to dairy or eggs. Pea protein is not absorbed as fast as whey protein but is absorbed quicker than casein protein.
There hasn’t been a lot of research into the muscle-building properties of pea protein, but at least one 12-week study involving 161 men doing resistance training who took either 50 grams of pea protein, whey protein or a placebo non-protein powder each day saw similar increases in muscle thickness between the pea and the whey protein groups. And both groups had superior gains to the placebo group so there could be something to the pea protein story here.
Even studies that use lower-quality protein such as that derived from wheat can elicit a significant muscle protein synthesis response if greater amounts of it are consumed. So this may be an effective strategy to compensate for its lower protein quality.
The story here is that adequate protein in the diet mostly trumps the source of protein – so long as the diet is varied. A variety of foods means a variety of different protein types.
What are the downsides?
So what about the downside of protein supplements? Outside of cost, there can be some negatives. For a start, they can move the focus away from the undisputed benefits of a varied training diet.
Purified protein preparations contain few of the other nutrients needed to support the building of muscle, and the protein they supply is usually not needed by athletes who eat food as they’re likely already meeting their requirements. The supplements then become excess protein which the body dismantles and uses for energy or stores as body fat.
Excess protein does not harm the kidneys in healthy people, but it has been linked to worsening pre-existing damage so it is something to be aware of if this could be you.
What it all means
For sports people, here’s what you need to know about protein: to maximise muscle growth with resistance exercise, daily protein recommendations sit at the upper end of about 1.6 grams per kilogram of body weight. Most people, especially the recreationally active, need less than this.
Protein goals are best achieved by spacing protein-containing meals and snacks throughout the day and aiming for 15 to 30 grams of protein at each eating occasion. There can be some cases when protein supplements make it more convenient to hit this goal, but these are the exceptions, rather than the norm. If you think it is hard for you to hit your protein goals, maybe look at your diet first before you reach for the protein supplement.
But the biggest performance gains in sport don’t come from protein supplements. They come from the triad of a broad varied diet, adequate rest and recovery, and the one supplement that all athletes need to be taking: it’s called BHW. Bloody hard work.