How Fast Do You Digest Whey Protein?

One reason whey protein is one of the most sought-after supplements on the market is because it works fast. Whether you’re drinking it post-workout to aid muscle recovery or pre-workout to help stimulate effort when things get tough, whey contains amino acids that can begin to appear in your bloodstream as soon as 15 minutes after you drink it.

It Takes Time

Whey is a “fast-acting” protein, which means your body is able to digest it relatively quickly. Still, that digestion process doesn’t happen all at once.
Whey shows up in your bloodstream just 15 minutes after you consume it, registered dietitian Jeffrey Volek says in "The Men's Health Big Book of Food and Nutrition." However, your drink is not completely digested in this amount of time. Exercise physiologist Helen Kollias notes on the Precision Nutrition website that it can take four hours or more for amino acid levels to peak in your body after drinking whey.

Whey Absorption

Digestion is not the same as absorption when it comes to whey, and your body is not able to use all of the nutrients from the foods and drinks you consume. Kollias states that you can absorb a maximum of 8 to 10 grams of whey protein per hour, and it takes about an hour and a half for whey to become absorbed within the digestive tract. That means if you drink a shake that has more than 15 grams of whey protein, your body might not have the opportunity to absorb and use all of that protein, and the rest could become waste products.

What's Your Whey?

Different brands of whey protein have different compositions, so not all of them will digest at the same rate. The three forms of whey protein powder are concentrate, isolate and hydrolysate. All three are fast-acting, but hydrolysates are more processed and are digested just a little bit sooner than concentrates or isolates. According to Volek, the difference is so minimal that it doesn’t give hydrolysates a clear advantage over concentrates or isolates, however.

Timing Is Everything

If your workouts are moderate and you don’t regularly strength train, it won’t make a big difference when you drink your whey supplement. For strength athletes and active people trying to build muscle mass, however, timing does matter. Kollias recommends drinking a whey shake within 15 minutes of finishing your workout to get the maximum benefits. This will help encourage muscle mass development, enhance workout recovery and alleviate sore muscles.