Whey Protein Research Analysis

Q: How much protein do I need per day?

Protein requirements differ depending on age, sex, activity level, and a multitude of other factors. Generally, most adults should consume 1.2 to 2.4 grams of protein per kilogram of body mass per day (g/kg/day) — sedentary individuals can likely obtain adequate protein near the lower end of this range, while active individuals and those looking to gain muscle should skew their intake toward the higher end. You don’t need to supplement to achieve your daily protein intake goals — protein can come entirely from whole foods or from a combination of whole foods and protein supplements (e.g., whey protein powder). However, protein powders can be a great and convenient way to get more protein. If you want more information on how to determine your optimal protein intake, check out our optimal protein intake guide or easily calculate your protein needs with our protein intake calculator. As for protein intake per meal, it seems that 0.4 g/kg/meal is optimal for stimulating muscle protein synthesis (MPS) for most younger adults; a dose of 0.4 to 0.6 g/kg/meal is best for older adults.[39][40] And no, your body doesn’t “waste” protein if you eat more than 30 grams in one sitting — this is a common myth.

Q: What’s the difference between the various types of whey protein?

Whey protein concentrate is the least processed form of whey protein and is 35%–80% protein by weight, although most whey protein concentrate powders tend to be standardized at 80% protein by weight.[54] Whey protein isolate is defined as being more than 90% protein by weight. Whey hydrolysate is protein that has been pretreated with enzymes and acid to reduce its peptide size; it’s the fastest absorbed form of whey. Hydrolysis reduces the allergic potential of whey and milk protein by breaking down immunogenic, larger peptides into smaller ones less-apt to be recognized by the immune system. This why hydrolyzed whey is often used in infant formula. Hydrolyzed whey also tends to have increased solubility compared to whey isolate, although it is important to note that whey protein in general (including whey isolate) is quite soluble. Several studies comparing whey hydroylsate to whey isolate and other milk proteins such as casein failed to make a difference in nutritional quality.[55] Is one form better than the others? Not necessarily, but this can vary by the individual. Since whey hyrolysates are inherently less immunogenic, they are useful for people who can't tolerate whey concentrate or isolate. As far as efficacy in-general, including their ability to faciliate muscle hypertrophy or recovery, there haven’t been many comparison studies. One trial noted that whey hydrolysate may enhance muscle recovery more than whey isolate.[56] Whether or not the differences observed in this trial would be experienced outside of a controlled laboratory setting is unclear.

Q: Do I need to take whey protein immediately after my workout?

The popular idea of an “anabolic window” — a crucial period of time before/after training during which protein must be ingested to maximize muscular adaptations — has been called into question. Indeed, the largest determinant of gains in muscle strength and hypertrophy seems to be total protein intake throughout the day (and a well-structured resistance training program), rather than nutrient timing per se.[41] But protein timing may not be inconsequential; exercise does have a “sensitizing” effect on muscles, and consuming protein in close proximity to a workout can ensure that one maximizes this anabolic sensitivity. Furthermore, exercising on an empty stomach can put the body into a negative protein balance; reupping on protein afterward helps maintain a positive protein balance to promote muscle protein synthesis instead of breakdown, and seems to be better than eating a protein-containing meal before or a few hours after working out.[42]

Q: Is whey protein superior to other protein sources?

Whey protein is highly bioavailable, rich in essential amino acid (including leucine), and quickly digested. Consuming whey causes a larger increase in blood amino acids than does casein or soy protein. And, both at rest and after exercise, whey protein stimulates muscle protein synthesis (MPS) to a greater degree than casein and soy — likely due to the quicker digestion and/or higher leucine content of whey hydrolysate.[43]

Q: Is whey protein safe to consume while pregnant or lactating?

Pregnant and lactating people may need more protein than previously recommended — 1.66 to 1.77 grams of protein per kilogram of body weight per day (g/kg/day) seems to be ideal,[44][45] with 1.5 g/kg/day being the lower threshold for maintaining a positive nitrogen balance.[46] Furthermore, some studies have observed that supplementing with protein during pregnancy seems to reduce infant health risks, including low gestational weight, low birth weight, and stillbirth.[47] While there haven’t been any studies on whey protein supplementation for pregnant/lactating people per se, there’s some evidence that maternal consumption of dairy protein — and in particular whey protein — may benefit infant weight and body composition.[48] However, whey protein (and other protein) powders come with the risk of being possibly contaminated with heavy metals or other pesticides. After all, dietary supplements (including protein powders) aren’t regulated by the Food and Drug Administration (FDA). Some protein powders may also include added sugar and other ingredients that pregnant/lactating people may want to avoid. The best advice: read the labels carefully, and always discuss any supplements with your obstetrician/gynecologist (OB/GYN) or other healthcare professional before implementing any dietary changes.

Q: Is whey protein effective for older adults?

Aging is associated with anabolic resistance — a muscle’s resistance to growth or stimulation of muscle protein synthesis (MPS) — making it harder to build or maintain muscle mass. In other words, older muscles require a greater dose of protein to stimulate a similar amount of MPS as younger muscles.[49] For this reason, older adults who want to build or maintain muscle may need more protein (per day and per meal) than the RDA recommends, and whey protein is a great source because of its potent ability to stimulate MPS. In adults older than 60, whey protein supplementation (often when combined with resistance training) increases physical function, improves lean mass/skeletal muscle mass and upper-body strength in those with sarcopenia/frailty,[50][51] and is effective for increasing total protein intake and MPS.[52] Whey protein and resistance training also help postmenopausal women build more upper body strength and lower-body lean mass.[53]

Brady Holmer

Whey Protein

•Last Updated: October 12, 2023

Whey protein is one of the two high-quality proteins derived from cow’s milk (casein being the other). Its high digestibility, quick absorption, and well-researched benefits for muscle gain and cardiometabolic health make it a popular protein supplement among athletes and older adults.

Dosage

Examine Database

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Whey Protein is most often used for

Brady Holmer, BS, PhD(c)

Nick Milazzo, MSc, MPH

Last Updated:October 12, 2023

Dosage Information
Examine Database
Research feed
Frequently asked questions
Update History
References

What is whey protein?

Whey protein is a collection of proteins found in whey, a byproduct of cheesemaking. When a coagulant (usually rennet) is added to milk, the curds (casein) and whey separate; whey protein is the water-soluble part of milk. Whey protein is often consumed as a supplement in the form of dry powders with various levels of processing that affect how concentrated a source of protein they are and how fast they’re absorbed. There are three main types of whey protein: whey concentrate, whey isolate, and whey hydrolysate.

How much protein do I need per day?

What’s the difference between the various types of whey protein?

What are whey protein’s main benefits?

Whey is considered to be a high-quality, well-absorbed source of protein with benefits that are similar to those of increasing protein intake in general, such as augmenting muscle gain when paired with resistance training, limiting muscle loss during low-calorie diets/aging, and modestly limiting fat gain during periods of excessive calorie intake (e.g., “bulking”).

Whey contains high levels of the amino acid leucine, which is the most proteogenic (capable of increasing muscle protein synthesis or MPS) amino acid. As such, whey may be more potent at stimulating MPS than other protein types.^[31] Furthermore, supplementing with whey may benefit blood pressure,^[32] endothelial function,^[33] and appears to improve several glycemic- and lipid-related biomarkers in adults with type 2 diabetes and other metabolic conditions.^[34]^[35]^[36]

Do I need to take whey protein immediately after my workout?

Is whey protein superior to other protein sources?

Is whey protein safe to consume while pregnant or lactating?

Is whey protein effective for older adults?

What are whey protein’s main drawbacks?

Some individuals may experience digestive discomfort, bloating, gas, or diarrhea after consuming whey protein, but this will depend on the dose and one’s tolerance. Whey protein concentrate contains the milk sugar lactose, so individuals with lactose intolerance may want to avoid this form of whey protein in favor of isolate/hydrolysate (which don’t contain fat and contain very little lactose, making these forms of whey protein tolerable by all but the most lactose-sensitive individuals).

Whey (and protein in general) does not harm the liver or kidneys, but high-protein diets can exacerbate or accelerate pre-existing damage. People with damaged livers or kidneys should exercise caution when increasing protein intake quickly without the guidance of a doctor. See more below: FAQ:can-eating-too-much-protein-be-bad-for-you-3

Furthermore, a 2018 report on protein powders found that of the 134 products tested, over 70% of them had detectable levels of lead and cadmium. However, no data were reported on whey protein powders specifically and it should be noted that “detectable” does not necessarily mean harmful.^[37]

Can eating too much protein be bad for you?

How does whey protein work?

Whey protein appears to resist coagulation in the stomach and pass quickly to the intestines (at least when compared to casein and other proteins). Leucine spikes in the blood approximately 40–60 minutes after the ingestion of whey protein,^[31] which is quicker than that observed for other protein sources (e.g., tuna, turkey, and egg).^[38] As such, whey rapidly stimulates muscle protein synthesis (MPS).

What are other names for Whey Protein?

Note that Whey Protein is also known as:

whey
whey concentrate
whey isolate
whey hydrolysate
hydrolyzed whey
whey protein powder

Whey Protein should not be confused with:

Milk protein
Casein protein

Dosage information

Optimal protein intake will vary depending on one’s unique goals, and you can use our protein intake calculator to estimate your optimal daily protein intake, which is based on the evidence presented in our optimal protein intake guide.

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