Why Protein is Essential for Strength & Muscle Gains

If your goal is to build muscle, getting enough protein is not optional—it is one of the fundamental pieces of the puzzle. Resistance training provides the stimulus for muscle growth, but your body also needs adequate protein and amino acids to repair and build new muscle tissue. Protein provides those amino acids and plays a central role in a process called muscle protein synthesis (MPS).

But how much protein do you actually need, and does more protein always mean more muscle? Modern research gives us some useful answers to address these questions.

Why is protein so important for muscle growth?

During exercise, muscle tissue is constantly being broken down at a microscopic level and rebuilt through proper recovery and nutrition. For muscle tissue to grow over time, muscle protein synthesis needs to exceed muscle protein breakdown. Resistance exercise stimulates muscle protein synthesis, telling the body, “We need to adapt to this training stimulus.” Consuming protein provides the amino acids needed to support that process.

Research indicates that resistance exercise and protein consumption work synergistically to stimulate muscle protein synthesis. In simple terms: resistance training provides the signal, while protein consumption provides the building blocks for muscle growth.

How much protein do you need?

For most people who regularly participate in resistance training, a daily intake of approximately 1.4–2.0 g of protein per kilogram of body weight is an evidence-based target. Research examining protein intake during resistance training provides important insight.

A large analysis involving 49 studies and 1,863 participants found that protein supplementation increased gains in muscle mass, muscle fiber size, and strength.  

For example, a person weighing 75 kg might aim for approximately:

- 1.4 g/kg: 105 g/day

- 1.6 g/kg: 120 g/day

- 2.0 g/kg: 150 g/day

This does not mean that everyone needs 150 g of protein every day. Rather, it illustrates why protein intake should be considered relative to body size, training status, goals, and overall diet. For many people looking to maximize muscle growth, around 1.6 g/kg/day is a practical target, with the broader range of approximately 1.4–2.0 g/kg/day providing flexibility.

One of the misconceptions surrounding protein is that “more is better.” It is easy to assume that if 100 g of protein is good, then 200 g must be twice as good. The research doesn't support that idea, as the previously mentioned study-analysis found that increasing protein intake beyond approximately 1.6 g/kg/day did not produce additional gains in fat-free mass during resistance training. That doesn't mean consuming more than 1.6 g/kg is harmful or completely useless. There may be situations where higher protein intakes are appropriate. For example, during periods of calorie restriction when someone is trying to preserve lean body mass. However, for the average person whose primary goal is muscle growth, there is little evidence that pushing protein intake extremely high will produce greater muscle growth. The goal should focus on consuming adequate amounts of protein, not excessive amounts.

Does protein timing matter?

You may have heard that you need to consume protein within a very small window immediately after your workout. While consuming protein before or after resistance exercise can support muscle protein synthesis, the overall amount of protein consumed throughout the day appears to be more important than obsessing over a precise post-workout window.

A practical strategy is to distribute protein relatively evenly throughout the day rather than consuming most of it at one meal. Research has suggested approximately 0.4 g/kg per meal, spread across at least four meals, as one approach for reaching around 1.6 g/kg/day while providing repeated opportunities to stimulate muscle protein synthesis. For a 75 kg individual, that would be approximately 30 g of protein per meal. This could look something like:

-              Breakfast: 25–30 g

-              Lunch: 30–35 g

-              Snack: 20–30 g

-              Dinner: 30–40 g

What about protein immediately after exercise?

Post-workout protein can certainly be useful, but is not necessary immediately after a workout. A 2023 analysis examining 116 randomized controlled trials and more than 4,700 participants found that protein supplementation around exercise was associated with improvements in muscle mass and strength, although the researchers also emphasized that more research is needed to determine the optimal timing and protein source. If you have eaten a protein-containing meal a few hours before training, there is generally less urgency to consume protein immediately after your final set. On the other hand, if you trained before breakfast or several hours have passed since your last meal, having a protein-rich meal or snack after training is a practical way to support recovery.

Does the type of protein matter?

Protein quality does matter, but you don't necessarily need supplements. High-quality protein sources tend to provide all of the essential amino acids in sufficient quantities. Examples include:

-              Eggs

-              Milk and dairy products

-              Greek yogurt

-              Cottage cheese

-              Chicken and turkey

-              Fish and seafood

-              Lean meats

-              Soy and other complete plant proteins

Whey protein can also be a convenient option, particularly for people who have difficulty meeting their daily protein target through food alone. A 2026 analysis examining 78 studies and 4,755 participants found that whey protein was among the protein supplements associated with improvements in fat-free mass and strength when combined with strength training. However, this does not mean that whey protein is inherently necessary for muscle growth, simply a convenient way of consuming protein. A protein shake is therefore best thought of as a supplement for whole foods, not a requirement for building muscle.

Protein becomes particularly important as we age

Protein isn't just important for bodybuilders or competitive athletes. As we get older, maintaining muscle mass becomes increasingly important for strength, mobility, independence, and quality of life.

Recent research continues to support combining resistance training with adequate protein intake in older adults. For example, a 2025  review and study-analysis found that combining protein supplementation with resistance training was more effective for improving muscle mass and strength than protein supplementation alone in older adults.

Similarly, a 2025 study examining interventions for sarcopenia found strong evidence supporting the combination of resistance/balance training with protein-based nutritional supplementation for improving muscle strength, muscle mass, and physical function.

Putting it all together

If you're trying to build muscle, focus on the fundamentals before worrying about supplements, meal timing, or specific types of protein. Your muscles need a reason to adapt, and consistent resistance training is the primary stimulus for muscle growth. For most people who train regularly, approximately 1.4–2.0 g/kg/day is a reasonable range, with around 1.6 g/kg/day being a practical target for maximizing gains for many individuals. Rather than consuming most of your protein at dinner, aim to include a meaningful protein source at each meal. Protein around your workout can be beneficial, but total daily intake and consistent training are more important than consuming a shake within a few minutes of finishing your workout. Prioritize whole food protein sources, and only use protein supplements if needed.

The bottom line

Building muscle requires more than simply lifting weights and drinking protein shakes. Resistance training provides the stimulus, while adequate protein provides the amino acids necessary to support muscle repair and growth.Muscle growth is a long-term adaptation—not something that happens from one workout or one protein shake.

References

Morton RW, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine. 2018.

Jäger R, et al. International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition.

Zhou HH, et al. Effects of Timing and Types of Protein Supplementation on Improving Muscle Mass, Strength, and Physical Performance in Adults Undergoing Resistance Training: A Network Meta-Analysis. International Journal of Sport Nutrition and Exercise Metabolism. 2024.

Mamerow MM, et al. Research on daily protein distribution and muscle protein synthesis.

Drummond MDM, et al. Which Protein-Based Dietary Supplements Most Effectively Enhance Fat-Free Mass and Strength Gains in Healthy Adults Undergoing Resistance Training? A Network Meta-Analysis. Translational Sports Medicine. 2026.