Nutrient timing is a topic that continues to cause confusion in the nutrition world. The importance of protein isn’t questioned, but the timing of when to take it is. Let's dive into what the research really tells us about pre-workout protein and its effects on athletic performance.

The Theoretical Framework: Why Pre-Workout Protein Should Work

The logic behind pre-workout protein consumption seems sound on paper. During exercise, muscle protein breakdown (MPB) occurs, while muscle protein synthesis (MPS) typically decreases. By consuming protein beforehand, you theoretically provide readily available amino acids that could:

• Minimise muscle protein breakdown during training 
• Maintain elevated blood amino acid levels throughout your workout 
• Support energy production through gluconeogenesis when carbohydrate stores run low 
• Prime the muscle-building response for post-workout recovery 

When it is broken down like this, it seems practical. But as we know, the research doesn’t always support such practical theories.

The Current State of Pre-Workout Protein Research

The scientific literature on pre-workout protein presents a nuanced picture that's far more complex than marketing claims suggest. While protein timing has received considerable attention in sports nutrition and people regularly taking protein shakes pre and post workout, the specific effects of consuming protein before exercise remain less clear-cut than many assume [Ref].

Recent comprehensive reviews indicate that while protein consumption around exercise (both pre and post) can enhance muscle protein synthesis, the immediate performance benefits of pre-workout protein consumption are modest at best. The picture becomes even more complex when we separate the effects on different types of exercise - strength training versus endurance activities show markedly different responses to pre-workout protein intake. [Ref].

The Strength and Power Story

The evidence for pre-workout protein improving acute strength and power performance is surprisingly thin. Consuming protein before resistance training can stimulate muscle protein synthesis and support strength development, especially when combined with a structured training program. Studies show that both pre- and post-workout protein intake can enhance muscle strength and lean mass, but the timing (pre vs. post) is less critical than overall protein intake and consistent resistance exercise [Ref] [Ref] [Ref] [Ref] [Ref].

The likely reason? Strength and power activities primarily rely on the phosphocreatine system and stored muscle glycogen, not circulating amino acids. Your muscles have enough stored energy to power through most typical strength training sessions without needing external protein support.

Evidence from Meta-Analyses and Trials

Meta-analyses confirm that protein supplementation during resistance training leads to small but significant increases in muscle strength, with optimal benefits seen at total daily intakes of 16–1.8 g/kg body weight [Ref] [Ref] [Ref]. 

Pre-workout protein, when paired with resistance training, can improve upper body strength and may promote greater fat utilisation post-exercise, but differences between pre- and post-workout timing are minimal [Ref].

In older adults, protein supplementation (pre- or post-workout) can help increase strength and muscle mass, but effects are less pronounced if baseline protein intake is already sufficient [Ref] [Ref] [Ref].

Key Claims and Evidence

Figure 1: Evidence table summarising claims about pre-workout protein and strength.

 

Key takeaway

Pre-workout protein supplementation can support strength gains, especially when total daily protein intake is adequate and combined with resistance training. However, the timing of protein (pre vs. post) is less important than meeting overall protein needs and maintaining a consistent training program.

The Endurance Evidence

In the endurance world carbohydrates dominate. Protein can often be an after thought but it plays an essential role in recovery and overall health. But does it help endurance performance?

Most studies show that consuming protein before endurance exercise does not significantly improve immediate endurance performance compared to carbohydrate or placebo [Ref] [Ref] [Ref] [Ref] [Ref].

Adding protein to pre-exercise carbohydrate drinks does not enhance time to exhaustion or time trial results, though it may help with next-day fatigue recovery [Ref] [Ref]. Some evidence suggests that protein supplementation during chronic endurance training can lead to small improvements in aerobic capacity (VO2max) and lean mass, but these effects are modest and not always observed [Ref] [Ref] [Ref] [Ref].

Recovery and Muscle Adaptation

Pre workout protein intake can help reduce markers of muscle damage and support muscle protein synthesis during recovery, especially when total daily protein intake is adequate [9] [Ref]. Protein supplementation through shakes, meals and snacks may also enhance training adaptations, such as lean mass gains and improved recovery, particularly during periods of high training volume or carbohydrate restriction [Ref], [Ref], [Ref]. However, the benefits for actual endurance performance are less clear.

Key Claims & Evidence

Key takeaway

Pre-workout protein does not reliably boost endurance performance compared to carbohydrates, but may help with muscle recovery and support training adaptations, especially when overall protein intake is sufficient. For most endurance athletes, prioritising total daily protein and carbohydrate intake is more important than timing protein specifically before workouts.

The Muscle Building Angle

While acute performance benefits are questionable, the muscle-building story is more compelling. Research has consistently shown that consuming protein around your workouts whether before, during, or after can enhance muscle protein synthesis and training adaptations over time.

The key insight from recent research is that total daily protein intake and distribution matter more than precise timing. The much-discussed "anabolic window" appears to be more like an "anabolic barn door" much wider than previously thought, especially if you're eating adequate protein throughout the day.

From a practical perspective though, taking a protein shake is a sensible way to help hit daily protein targets and can be consumed easily pre or post training or as part of a snack.

Evidence from Meta-Analyses and Trials

• Meta-analyses and systematic reviews consistently find that protein supplementation, when combined with resistance training, leads to greater gains in muscle mass and strength compared to training alone [Ref, Ref, Ref].
• The timing (pre- vs. post-workout) does not appear to make a significant difference for muscle hypertrophy or strength, as long as protein is consumed close to the workout and daily intake is sufficient [Ref, Ref, Ref].
• For optimal results, aim for 1.6–2.2g protein/kg body weight/day, with 20–40 g of high-quality protein per meal, distributed evenly throughout the day [Ref, Ref, Ref]

The Energy Question

When it comes to energy things such as caffeine, b vitamins, carbohydrates are often thought of first. You see, protein is not a preferred fuel source for immediate energy during exercise. Your body would much rather burn carbohydrates or fats. Converting protein to glucose through gluconeogenesis is metabolically expensive and typically only occurs when other fuel sources are depleted.

Some people report feeling more energetic after consuming protein before workouts, but this is likely due to:

• The psychological effect of following a pre-workout ritual
• Stabilised blood sugar levels (if the protein is consumed with carbs)
• Reduced hunger during the workout (this can have a performance benefit in itself)
• The presence of other ingredients in protein supplements (caffeine, B vitamins, etc.)

Protein is not an efficient fuel source so your shake, unless it contains carbs, caffeine or other active ingredients, isn’t helping your energy levels that much.

Conclusion

While pre-workout protein consumption can enhance muscle protein synthesis and will help with augmenting recovery from exercise, it doesn’t have much benefit for immediate performance improvements.

The evidence suggests that there is a hierarchy of importance to focus on. 

• Overall intake
• Some protein around workouts (pre, intra or post)
• Distribution of 20-40g per meal

Focusing on adequate daily protein intake, proper pre-exercise carbohydrate consumption, and consistent nutrition and supplement habits will yield better results than obsessing over precise protein timing. Pre-workout protein consumption appears to be a minor optimisation strategy rather than a fundamental requirement for exercise performance.