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 now, would they!?) , 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’s relatively cheap (when compared to casein and other proteins, at least), it has a high nutritional value and it’s low in fat. So, perfect for supplementing your daily protein intake, right?

Unfortunately, this isn’t always the case, but what exactly are the side effects of whey protein?


#1 – Lactose Intolerance

One of the most commonly seen 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.

If you do happen to be lactose intolerant, it’s probably better to opt for whey protein isolate rather than a whey protein concentrate as these typically contain a lower percentage of lactose.


#2 – Ketosis

Ketosis; a condition caused by high levels of ketone in the blood, is another common side effect associated with 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 (i.e. you have a low body fat percentage), 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, the liver is 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 huge amount of pain and can also cause infection and long term damage in some cases.

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 100% 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 thought that Whey protein powder can 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’s 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’s important to remember that whey protein can also have a hugely beneficial and positive effect on your body. If you’re trying to gain muscle mass and are regularly hitting the gym, it’s likely that whey protein will be hugely beneficial as part of your diet if consumed in the correct quantities AND at the right times of the day.

Whey protein powder has the power to increase your metabolic rate, drastically reduce muscle recovery times and much more; just make sure to invest in a decent quality one!

So many of the cheaper alternatives are filled with crap “filler” content and additives that typically offer no nutritional value whatsoever and in some cases, can even be harmful. Make sure to check out my list of the 10 best protein powders if you’re not sure which one to go for.

If you are still concerned about the health risks surrounding protein powders in general, you can also check out my blog post; Are protein shakes bad for you? I delve deeper and explore how protein powders could be causing a negative effect on your body, even if you you haven’t experienced any of the side effects mentioned above.

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