The Protein Bible: Part 4 - Protein and Amino Acid Timing

By Kurtis Frank and Sol Orwell

The four part breakdown to this protein guide:

Taking a supplement is usually pretty easy. Look at the label and follow the instructions. Simple.

Alas, protein is not that simple. There are many things to potentially consider when taking protein, including:

  • Taking your protein before and/or after a workout session.
  • Taking a fast protein, or a slow protein, depending on the time of day.
  • Taking specific amino acids.

So for those who want to optimize their diet- what’s the best way to take your protein?

Timing Around Workouts?

The typical recommendation is to take protein right after your workout. Some people are so obsessive that they literally run to get their “post-workout shake” once their workout ends.

Too bad it’s a waste of time:

  • This post workout ‘window’ definitely does apply for the purpose of glycogen replenishment (carbs), but does not apply to muscle protein synthesis.
  • The majority of the research on post workout shakes was conducted in fasted training, not fed training (and as will soon be explained, even if you do train ‘fasted’ there is a better option than a post workout shake).

There have actually been direct investigations into whether supplementation of protein surrounding a workout in fed states is better at promoting muscle growth than taking the same protein at times away from the workout. Subjects were divided into one of two groups:

  • Two servings of quickly absorbed protein, immediately before and immediately after a workout.
  • The exact same servings of protein taken upon waking and before sleep.

The result? No significant differences found [1] [2]. The primary factor was having protein intake high (as we’ve recommended in the previous parts). Timing was found to be irrelevant.

As long as you get enough protein and are training after having eaten in the day, protein timing is not important.

The one exception to protein timing is if you go to the gym in a fasted state [3] (popularized by Martin Berkhan). Even then, post-workout did not mean “consume immediately,” as taking protein 1 to 3 hours after the workout is not significantly different [4] [5].

There may be a reduction in soreness (DOMS) if you take protein [6] or BCAAs [7] before a workout (but not after).

If you train fasted, then taking protein soon after you workout can have benefits. There are more benefits if you take protein before than after your workout (which ironically means you are not training fasted).

The speed of absorption?

Marketing for protein loves to obsess over fast and slow protein, so much so that people commonly associate whey as “fast” and casein as “slow.”

Technically, there are differences in absorption rates, and the general fast-to-slowest order is:

Hydrolyzed casein >= Hydrolyzed whey > Whey Isolate >= Whey concentrate > Other protein sources > Casein

Basically the two hydrolyzed are the fastest, then the whey variants, then other protein sources, and then finally casein protein.

But does it matter?


It’s a mess of research, but the general points are:

  • Muscle protein synthesis seems to be correlated with how fast protein enters your blood.
  • However, these are short-term studies. If we actually look at muscle mass (which is what we really care about), there is some evidence that slower proteins build more muscle.
  • Thus, slower proteins may be better as they get absorbed more efficiently.

Although faster proteins increase muscle protein synthesis more than slower proteins, slower proteins may actually yield more muscle mass. Still, worrying about protein absorption is not important for the average person.

What About Amino Acids Supplements like BCAAs, Glutamine, Leucine, and More?

There are a lot of sports supplements that are just extractions of amino acids found in protein, and some of the major ones are:

  • L-Glutamine
  • All three BCAAs (Leucine, Isoleucine, Valine)
  • HMB and Leucic acid (both metabolites of leucine)

These amino acids are great and all, but you don’t need to supplement them if you ingest enough protein. This is because the protein you are taking will give you more than enough glutamine and BCAAs, and leucine will convert into its metabolites in your body.

Still, there are some other amino acids to consider:

  • Some amino acids, like l-carnitine and taurine, are not highly present in protein and so supplementation could still be considered despite high dietary protein intake.
  • HMB for the specific purpose of anti-catabolism is apparently 20-fold more potent than leucine, so a 3g dosage of HMB is as anti-catabolic as 60g leucine. HMB can be a very useful supplement when cutting.
  • The supplements mentioned earlier can be useful as supplements if your diet has gone down the toilet.

Amino acid supplements (in reference to glutamine and BCAAs mostly) are not required if protein intake is high, but could be useful in specific situations. There are a few amino acids that may be worthwhile supplementing.

Summing up Part 4

  • If you are working out and are not fasting, your total protein consumption matters, not your timing.
  • If you are working out and are fasted, then timing can matter. However, pre-workout protein is more beneficial than post-workout.
  • Worrying about the speed of absorption is a waste of time.
  • Glutamine is useless if you eat enough protein.
  • BCAAs are useless if you eat enough protein, except perhaps when fasted training.
  • HMB is useful when cutting.

The Complete Protein Bible:


Kurtis Frank and Sol Orwell founded Examine.com in early 2011 to help make sense of scientific research on supplementation and nutrition. Independent and unbiased, they recently have released the Supplement-Goals Reference in order to make it easy to figure out which supplements work (and which are hype).

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