Whey Protein

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Whey protein is a collection of proteins found in whey, a byproduct of cheesemaking. When a coagulant (usually renin) is added to milk, the curds (casein) and whey separate; whey protein is the water-soluble part of milk. As a supplement, it’s sold as dry powders with various levels of processing that affect how concentrated a source of protein they are and how fast they’re absorbed.

It’s a high quality, well-absorbed source of protein that’s very useful for hitting targeted daily protein goals. Its benefits extend to the benefits of increased protein intake in general, such as augmenting muscle gain in conjunction with resistance training, limiting muscle loss during low-calorie diets, and modestly limiting fat gain during periods of excessive calorie intake. These effects aren’t exclusive to whey protein but it will likely be more effective than most other protein sources per gram.

Whey does not harm the liver or kidneys, but it can exacerbate 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: can eating too much protein be bad for you?

The amount of whey protein to supplement depends on individual daily protein goals. For example:

• If you are an athlete or highly active person attempting to lose body fat while preserving lean muscle mass, a daily intake of 1.5-2.2g/kg bodyweight (0.68-1g/lb bodyweight) is a good goal.

• If you are an athlete or highly active person, or you are attempting to lose body fat while preserving lean mass, then a daily intake of 1.0-1.5g/kg bodyweight (0.45-0.68g/lb bodyweight) is a good goal.

• If you are sedentary and not looking to change body composition, a daily target of 0.8g/kg bodyweight (0.36g/lb bodyweight) is a good goal.

If daily protein targets are achieved through dietary protein alone, supplementation is unnecessary. Obese individuals should not follow the above recommendations, as bodyweight calculations would result in very high dosages. Obese people should calculate their protein targets based off of what their weight would be, assuming an overweight BMI.

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what effects whey protein has on your body, and how strong these effects are.

Grade	Level of Evidence [show legend]
	Robust research conducted with repeated double-blind clinical trials
	Multiple studies where at least two are double-blind and placebo controlled
	Single double-blind study or multiple cohort studies
	Uncontrolled or observational studies only

Level of Evidence ? The amount of high quality evidence. The more evidence, the more we can trust the results.	Outcome	Magnitude of effect ? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.	Consistency of research results ? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.	Notes
	Fat Mass	Minor	Moderate See all 6 studies	Inclusion of dietary protein in the diet above the recommended daily intake appears to aid the process of fat loss during hypocaloric diets (eating less than required to sustain body weight). There is currently no demonstrated benefit with whey protein over other protein sources.
	Insulin	Minor	Low See all 5 studies	Mixed effects on insulin, as there is an acute increase due to whey being a protein source (although whey increases insulin more than other proteins). Fasting insulin (chronically) tends to either be not affected or reduced, although the latter is usually confounded with weight loss.
	Lean Mass	Minor	Moderate See all 4 studies	Protein in general increases lean mass, but there is not a significant body of evidence to support whey protein as being more effective than other protein sources
	Power Output	-	High See all 3 studies	There doesn't seem to be an inherent effect of protein on power output, although it may augment training-induced power accural (an inherent effect of protein supplementation).
	Weight	-	Moderate See all 8 studies	The influence of whey protein on weight per se is highly unreliable, and is subject to the overall context of the diet. Protein in general can aid weight loss attempts and is required to build lean mass, with whey not having any demonstrated benefit over other protein sources.
	Muscle Protein Synthesis	Notable	Very High See all 3 studies	Whey protein appears to increase muscle protein synthesis to a higher degree than other protein sources acutely, although over the prolonged supplementation it seems comparable in potency.
	Anti-Oxidant Enzyme Profile	Minor	Very High See 2 studies	Increased levels of glutathione are secondary to the Cysteine content and can be mimicked with all dietary sources of L-cysteine or supplemental N-acetylcysteine
	Ghrelin	Minor	- See study	A decrease in Ghrelin has been observed with whey protein supplementation.
	Insulin Sensitivity	Minor	Very High See all 3 studies	Has been noted to increase insulin sensitivity to a larger degree than casein when consumed by obese persons in a part of a fat loss diet; has not yet demonstrated an insulin sensitizing effect in lean athletes
	LDL-C	Minor	- See study	Possible LDL-C lowering effect, but has not yet been shown to be better than other protein sources.
	Triglycerides	Minor	Very High See 2 studies	Possible reductions in triglycerides, but it is not sure if this is exclusive to whey protein or due to protein in general.
	Blood Flow	-	- See study	Insufficient evidence to support a role of whey protein in improving blood flow
	Blood Glucose	-	Very High See all 5 studies	No significant influence on fasted blood glucose levels, may decrease postprandial glucose levels (relative to no protein ingestion) due to the release of insulin
	Blood Pressure	-	Very High See 2 studies	Insufficient evidence to support the blood pressure reducing effects of whey protein
	Bone Mineral Density	-	Very High See 2 studies	Currently no demonstrated benefit to bone mineral density, although protein in general appears to have a protective effect
	C-Reactive Protein	-	- See study	No demonstrated effects on C-Reactive Protein
	HDL-C	-	Moderate See 2 studies	No significant evidence to support an increase in HDL-C with whey protein
	IGF-1	-	- See study	Does not appear to inherently alter circulating IGF-1 levels
	Inflammation	-	- See study	Insufficient evidence to support whey protein as interacting with inflammation and biomarkers of inflammation
	Total Cholesterol	-	Very High See 2 studies	No significant influence on circulating cholesterol has been demonstrated with whey protein
	Appetite	Minor	- See study	Appears to reduce appetite (common to all protein sources), but its superiority over other protein sources is not yet demonstrated.
	Intestinal Permeability	Minor	- See study	Appears to decrease intestinal permeability, which is due to the glutamine content of whey protein.
	Liver Enzymes	Minor	- See study	Has been associated with a decrease in liver enzymes (in steatohepatitis) but not to a remarkable degree; may simply be due to the L-cysteine content.
	Liver Fat	Minor	Very High See 2 studies	Reductions in liver fat have been noted with whey protein supplementation, which is thought to be more effective than other protein sources due to the high L-cysteine content.

Studies Excluded from Consideration

• Excluded due to being a mixture of whey, casein, and soy protein^[5]

• Does whey supplementation help muscle function recover after lifting?

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