Whey Protein Isolate Side Effects

Whey Protein Isolate, commonly known as WPI is one of the most popular protein supplements around. What sets it apart from other proteins is its extremely fast absorbing nature and its purity, often being free of lactose, carbohydrates and fats. A predominant ingredient fixture of many blended protein supplements, WPI by itself is one of the best supplements for advanced trainers looking to maximise their recovery and growth capacity. But are there any side effects associated with whey protein isolate supplementation?

Whey Protein Isolate (WPI) Benefits

Before looking at any potential side effects of whey protein isolate, let’s examine the many benefits of WPI. Whey protein isolate as previously mentioned is an extremely fast absorbing protein source. As such, it breaks down quickly and the amino acids are easily shuffled into the muscles at breakneck speed to help stimulate muscle building and recovery. Whey protein isolates are also extremely low in carbohydrates and fat, making them a great protein source for those trying to limit their caloric intake. Additionally, whey protein isolates contain more bioactive peptide fractions than less pure whey proteins, which can further benefit growth and recovery from exercise.

Whey Protein Isolate (WPI) Side Effects

Whey protein isolate consumption comes with very few negative side effects and is one of the most easily tolerable supplements around. Due to its ultra pure nature and its easy digestibility, most users find that it is one of the few protein powders that is almost universally acceptable. Here we take a quick look at some of the most commonly suggested side effects of WPI supplementation.

Whey Protein Isolate (WPI) Side Effects - Constipation

Many people consuming protein powders tend to find themselves becoming constipated with harder and less frequent stools. Protein is said to be dehydrating by many people which can lead to more water being drawn back into the body resulting in harder, more dehydrated stools, which slows transit time. While there’s plenty of anecdotal evidence to suggest this is the case, there are very few studies which actually support this¹. To avoid potential constipation from high protein intake, it’s important to maintain hydration and ensure you’re still consuming adequate fibre.

Whey Protein Isolate (WPI) Side Effects - Cholesterol

Another common concern with whey protein isolate supplementation is its effect on cholesterol levels. However, this is more of an issue with high protein diets being the culprit. High protein diets are often also high fat diets, which if uncontrolled for can result in rises in cholesterol. As such, it is important to consume your food proteins as lean meats, fish and vegetarian proteins such as beans and soy, whilst ensuring the fats in your diet are mostly unsaturated.

Whey Protein Isolate (WPI) Side Effects - Allergic Reactions

People who experience allergic reactions to milk should avoid whey protein isolate supplements and indeed all dairy protein supplements. This is because most allergic reactions to dairy are due to one of the many proteins in milk and dairy, with one of the most common being that of alpha S1-casein. Milk protein allergies are very different to that of lactose intolerance and many lactose intolerant individuals find that whey protein isolate is suitable for continued use. Due to the extremely low to zero lactose and carbohydrate content, WPIs are ideal protein supplements for those who want to stick to a dairy based protein.

Whey Protein Isolate (WPI) Side Effects - Joint Pain

Joint pain is another common proposed side effect of whey protein isolate consumption. There’s no evidence to support a link between WPI and joint pain. However, in certain circumstances, high protein diets can result in flare ups of existing joint conditions. This is especially true for protein sources with a high omega 6 to omega 3 ratio, which is associated with higher incidence of inflammation and inflammatory conditions such as arthritis². High meat diets are also linked to gout³, which can result in joint pain. Whey protein isolate consumption alone is not linked with joint pain.

Whey Protein Isolate (WPI) Side Effects - Kidney

Perhaps the most common concern with protein supplementation is its effect on kidney health. High protein diets result in an increase in nitrogen status in the body which needs to be excreted through our kidneys. Increased protein consumption, from food or supplements such as whey protein isolate were originally thought to be a possible stressor to the kidneys. However, more recent studies have shown that a person with healthy kidney function can tolerate up to 2.8g/kg of bodyweight of protein⁴. So unless your kidneys are on the decline, feel free to have some more WPI.

Whey Protein Isolate (WPI) Side Effects - Rash

A fairly rare negative side effect, there’s really no support that whey protein isolate can result in a rash by itself. Rather it is usually a manifestation of an already inherent hypersensitivity to certain proteins such as the alpha S1-casein protein found in milk and dairy.

Whey Protein Isolate (WPI) Side Effects for Men

There aren’t really any side effects of higher protein supplement intake which are sexually distinct. A common misconception is that higher protein diets may result in hair loss and baldness, but there is no scientific backing for this proposed side effect.

Whey Protein Isolate (WPI) Side Effects Review

Overall, as shown above, there are very, very few negative side effects directly associated with whey protein isolate supplementation. In fact, unless you’ve already got a pre-existing allergy or intolerance, there should be no reason why you shouldn’t be investing in a good WPI supplement, as the benefits definitely outweigh the negatives.

1. Martin WF, Armstrong LE, Rodriguez NR. ‘Dietary protein intake and renal function.’ Nutr Metab (Lond). 2005 Sep 20;2:25.
2. J Nutr Metab. 2012;2012:539426. doi: 10.1155/2012/539426. Epub 2012 Apr 5.
3. Choi HK, Atkinson K, Karlson EW, Willett W, Curhan G. ‘Purine-rich foods, dairy and protein intake, and the risk of gout in men.’ N Engl J Med. 2004 Mar 11;350(11):1093-103.
4. Poortmans, J.R. and Dellalieux O. (2000) Do regular high protein diets have potential health risks on kidney function in athletes? International Journal of Sport Nutrition & Exercise Metabolism 10, 28-3