Whey Protein Powder Side Effects; What Are They?

Whey protein has come a long way in terms of popularity over the past 10 – 20 years. Once a nutritional supplement used only by the most hardcore bodybuilders in the 1970′s and 80′s, Whey protein powders are now used by hundreds and thousands of bodybuilders and athletes around the world, but why is this? Well, Whey is an excellent source of protein and there are many benefits including its fast digestibility and low carbohydrate content.

However, there are a number of Whey protein powder side effects and dangers that are rarely publicised by the nutritional supplement companies (they wouldn’t want to harm sales) , but can seriously damage your heath when taken in excess amounts.


How Are Whey Protein Powders Made?

Not surprisingly, Whey protein powders are made from Whey; a liquid that remains once milk is curdled and strained. Whey protein is obtained as a natural by-product from the cheese manufacturing process and is a great source of protein, which is why it is now commonly used as a nutritional supplement for those looking to increase muscle mass and tone.

Whey protein has a lot going for it; it is relatively cheap (when compared to casein and other proteins), it has a high nutritional value and is low in fat. So, perfect you might think for supplementing your daily protein intake; unfortunately, this isn’t always the case, but what exactly are the side effects?


#1 – Lactose Intolerance

One of the most commonly seem Whey protein powder side effects is by those that are lactose intolerant. Because Whey protein is a by-product of the cheese manufacturing process, which is created almost entirely from milk, Whey protein powders usually contain between 5% and 6% lactose. Those that are lactose intolerant are unable to handle Whey protein powders and often develop a number of symptoms such as diarrhoea, nausea, flatulence, abdominal cramps and bloating.

Usually, these symptoms will develop around 30 minutes to 2 hours after consuming Whey protein. For anyone that is lactose intolerant, it is probably better to opt for Whey protein isolate rather than a Whey protein concentrate as this will contain a lower percentage of lactose.


#2 – Ketosis

Ketosis; a condition caused when there are high levels of ketone in the blood, is another common side effect when it comes to Whey protein powders. Ketone is produced by the liver in a process named ketogenesis and it occurs when the glycogen stores in the liver are depleted. The cause of this is a high protein, low carbohydrate diet. Because carbohydrates are used as the bodies primary source of energy, a low carbohydrate diet will force the body to resort to using other sources of energy. If the body is depleted of carbohydrates to use as fuel then it will resort to using fat to provide energy. If there is only a small amount of fat available, the body will then start to break down proteins to provide energy.

Because the body starts to use fat as a main source of energy for those on a high protein, low carbohydrate diet, livers are often damaged due to ketosis.


#3 – Kidney Damage

Kidney damage is also a concern for those drinking excess amount of whey protein powder and kidney stones are quite common. Kidney stones are usually caused when the components of urine are out of their natural balance. When the minerals in your urine are not diluted enough, tiny hardened mineral deposits can form known as kidney stones. These can cause a significant amount of pain and can cause infection and/or damage too.

Consuming too much protein causes your kidneys to become overworked and thus, they become less effective at flushing away the by-products obtained from the breakdown of protein. This is one of the more severe side effects of Whey protein consumption and luckily, it is usually a problem reserved for those consuming excess amounts of protein powder on a regular basis.


#4 – Osteoporosis

Another of the Whey protein side effects that has never been proven is the onset of Osteoporosis; a disease in which bones become brittle and fragile with an increased risk of fracture and/or breakage. It is considered that Whey protein powder could lead to the onset of Osteoporosis due to the way that high amounts of protein often lead to the loss of bone density, caused by an imbalance of minerals in the bones.

However, this is not a scientifically proven Whey protein side effect and once again, it is more than likely a side effect that is only going to occur when an excess amount of protein is consumed.



Whey protein powder may have a number of side effects as listed above, but it is important to remember that Whey protein can also have a hugely beneficial and positive effect on your body. If you are trying to gain muscle mass and are regularly hitting the gym, it is likely that Whey protein will be hugely beneficial as part of your diet if consumed in the correct quantities at the right times of the day.

Whey protein powder increases metabolic rate and muscle recovery time, whilst also decreasing muscle recovery times and is a great source of protein post-workout.

If you’re concerned about the health risks surrounding protein powders in general, then check out our blog post; Are protein shakes bad for you? This delves deeper and explores how protein powders could be causing a negative effect on your body, even if you don’t experience any of the side effects mentioned in this article.