Protein for Runners: Do You Need It After Running?

Not every runner needs a protein shake after training — but some definitely do. If you’ve been wondering whether to add protein to your post-run routine, you’re not alone.

I’ve taken protein after every run for several years now. That said, I don’t think all runners need to supplement. Whether you should depends on your training volume, goals, and overall diet.

In this article, I’ll explain which runners truly need protein, why it matters, and what type to choose. I’ll also share some products I’ve personally tested.

By the end, you’ll know whether protein supplementation makes sense for you — and how to do it right.

Why Runners Need More Protein Than Non-Runners

To understand whether you need protein supplements, we first need to establish that runners genuinely require more protein than sedentary people.

Runners who train at high volumes need more protein than non-runners. The reason: protein is used as an energy source during running training.

The primary fuel sources for running are carbohydrates and fat. However, during high-intensity or prolonged sessions, as carbohydrate stores decline, amino acids (protein) increasingly contribute to energy production.

The body maintains an amino acid pool and constantly cycles between protein synthesis and proteolysis. When amino acid availability is high, synthesis dominates. When it drops, protein breakdown accelerates to replenish the pool.

When training depletes amino acids, the body ramps up protein breakdown to restore the amino acid pool. The details are covered in the related article below.

When protein breakdown accelerates, the following can occur:

If your goal is to run faster, you need to recover from training stress and allow your body to progressively adapt to the load you’re applying.

Insufficient protein delays recovery and blunts adaptations like mitochondrial biogenesis and capillary development — making it harder to extract the full benefit from your training.

While marathon runners should carry only the muscle mass they need, severely inadequate nutrition can result in losing even the muscles essential for running.

Who Needs Protein Supplements — And Who Doesn’t

Here’s a breakdown of runners who likely need protein supplements versus those who don’t.

The more frequently you run and the more performance-focused your training is, the higher your protein needs. High training frequency creates more opportunities for protein depletion.

As a rough benchmark, runners covering 5 or more days per week or 60–70+ km weekly may benefit from supplementing with protein.

Whether you need to supplement also depends on your overall diet, not just training. If you can eat a balanced meal right after a run, a protein shake may not be necessary.

That said, if your regular meals fall short on protein, supplementation can fill the gap. The generally recommended intake for runners is 1.2–2.0 g of protein per kg of body weight per day※1 ※2. For a 60 kg runner, that’s roughly 72–120 g.

The wide range reflects individual variation and carbohydrate intake. When carbohydrate availability is sufficient, the body is less likely to draw on protein for energy — reducing protein requirements.

Runners eating a lower-carb diet will need proportionally more protein to compensate.

Whey vs. Soy Protein: Does It Matter for Runners?

There’s plenty of debate over whether whey protein or soy protein is better for runners. The short answer: for most purposes, the difference is minimal.

Runners take protein not to build muscle, but to prevent protein breakdown, support recovery, and promote training adaptations. For this purpose, fast-absorbing whey protein powder isn’t strictly necessary.

What matters is maintaining adequate protein availability throughout the day — not just the post-workout window. The difference in absorption speed between whey and soy matters far less for endurance runners than it does for bodybuilders.

On the muscle-building side, a meta-analysis of nine studies found no significant difference between whey and soy protein in long-term muscle mass and strength gains※3. For runners, who aren’t prioritizing hypertrophy, the choice matters even less. What counts is simply avoiding protein deficiency.

Here’s how to choose between the two:

Animal and plant proteins differ in their amino acid profiles, and a 1:1 ratio is generally considered ideal. If your diet already leans heavily on animal protein (meat, eggs, dairy), choosing soy protein can help rebalance your intake.

Why Taking Protein With Carbs Speeds Up Recovery

Preventing protein breakdown isn’t just about eating enough protein — carbohydrate intake plays an equally important role. When carbohydrates are insufficient, the body enters an energy-deficient state and accelerates protein breakdown to compensate.

To prevent this, consume adequate carbohydrates before and during training, and refuel with carbohydrates as quickly as possible after finishing.

The shorter the gap between finishing a run and refueling with carbohydrates, the faster muscle glycogen recovery. Research shows a significant difference in glycogen recovery rate between groups who consumed carbohydrates immediately post-exercise versus those who waited two hours.

The single most important recovery action after training is consuming carbohydrates as soon as possible.

In practice, however, meal timing and quantity don’t always work out perfectly. When you can’t fully replenish carbohydrates right away, consuming protein alongside carbohydrates can support glycogen recovery※4 ※5.

Regardless of carbohydrate intake, consuming protein after exercise also promotes muscle repair and synthesis. Aim to pair carbohydrates and protein together as soon as possible after your run to accelerate recovery.

How to Choose a Protein Powder for Running

Here are some protein powders I personally use. For runners, the core goal is preventing protein breakdown — so any protein that achieves this is fine.

Protein powders range widely in price. When choosing, consider the following criteria:

Protein powders that use artificial sweeteners tend to be cheaper. Those that avoid them typically rely on natural sweeteners like stevia instead.

Below is a comparison of protein powders I’ve personally tested (Japanese brands):

Product	Soy Protein	Whey Protein	G Whey Protein 100 Standard	uFit Whey Protein	matsukiyo LAB Soy Protein 100	uFit Soy Protein
Brand	Nichiga	Nichiga	Ultimate Life	uFit	matsukiyo	uFit
Protein Type	Soy	Whey	Whey	Whey	Soy	Soy
Artificial Sweeteners	Not used	Not used	Used	Not used	Used	Not used

My Post-Run Protein Routine

If you want to take carbohydrates and protein together, choosing a protein powder that already contains carbohydrates is the simplest approach. You can also make your own by mixing glucose or maltodextrin into a plain protein powder.

Personally, I mix Nichiga’s additive-free protein powder with glucose to make my own recovery protein shake.

I don’t have a strong preference for whey or soy — lately I’ve been using Nichiga’s soy protein.

A protein powder that includes carbohydrates is marketed as a recovery protein. Commercially available recovery proteins — and how to make your own — are covered in a separate article on Running Scientist.

References

※1 Tarnopolsky M (2004) “Protein requirements for endurance athletes” Nutrition

※2 Jäger R et al. (2017) “International Society of Sports Nutrition Position Stand: protein and exercise” J Int Soc Sports Nutr

※3 Messina M et al. (2018) “No Difference Between the Effects of Supplementing With Soy Protein Versus Animal Protein on Gains in Muscle Mass and Strength in Response to Resistance Exercise” Int J Sport Nutr Exerc Metab

※4 Craven J et al. (2021) “Carbohydrate-Protein Co-Ingestion for Endurance Performance and Recovery: A Systematic Review and Meta-analysis” Sports Medicine – Open

※5 Alghannam AF et al. (2018) “Restoration of Muscle Glycogen and Functional Capacity: Role of Post-Exercise Carbohydrate and Protein Co-Ingestion” Nutrients