The Ultimate Guide to Whey Protein: Benefits, Side Effects & FAQs

If you are looking to build muscle then chances are you have looked into buying a whey protein supplement.

Before you go rushing into buying the first supplement you find perhaps you should read the following article to see what you should be looking for.

Our guide will show you what the benefits of whey protein are if there are any potential side effects and will show you which supplement is best for your goals.

The Importance of Protein for Muscle Growth

There are plenty of reasons why you need to be consuming adequate amounts of protein in your diet.

Without adequate protein consumption, you will find that building muscle will be incredibly difficult.

Protein is essential for muscle protein synthesis (MPS). When you exercise your muscles will experience microscopic tears. The protein will help to repair this damage, enabling your muscles to grow and to become stronger too.

The Dietary References Intakes recommends that you consume 0.8g of protein for every kg you weigh daily 1.

However, if you are working out regularly, for example, if you are an athlete then the Journal of Sports Science recommends that you increase this amount to 1.3-1.8g of protein per kg 2.

If you weigh 90kg, for example, you would need to consume between 117-162g of protein daily.

This seems like a huge amount of protein to consume on a daily basis, which is why protein shakes are so appealing.

Rather than having to fit your protein needs into 3-4 meals you can supplement your intake with a couple of extra shakes.

What is Whey Protein?

Whey is the liquid that remains after milk has curdled and strained. It is the byproduct of cheese manufacture and has many commercial uses, including whey protein that is used as a supplement by athletes, bodybuilders and increasingly by the general public.

Historically whey was considered a waste product and was pumped into the rivers and streams of the USA. However, this led to an increase in algae growth due to the protein content.

Eventually, this practice was prohibited, as this algae growth prevented sunlight and oxygen from reaching the water.

To create whey protein, whey is pasteurised just like you would milk, to ensure bacteria is removed.

It is heated to a temperature of 70-80° Celsius before being cooled back down to 4°. It is this warming and cooling that eliminates the bacteria without causing the whey to coagulate into one solid mass.

The next step is to filter the whey. Using a web of ceramic filters and stainless steel turbines the lactose and fats are removed leaving a liquid.

This liquid is then dried in a massive dryer that uses hot then cold air.

Finally, the solid mass is blended to create the powder before being mixed with other flavours (such as chocolate and vanilla) to mask the chalky taste.

Types of Whey Protein

There are 3 main types of whey protein; concentrate, isolate and hydrolysate.

The cheapest form of whey protein is concentrate. This is because it is the type that typically contains the highest amount of carbohydrates.

When looking at whey protein, you should opt for those with the highest percentage of protein. Concentrate can contain a concentration of between 29% to 89%, although typically it is sold with a concentration between 70% and 90%.

Whey protein isolate is a more refined type, and will usually contain a concentration of over 90%.

When it is being refined, fat and lactose is removed. This results in fewer fats and carbs remaining.

Hydrolysate whey protein is refined even further, so contains the least amount of fats and carbs.

This final type of whey protein is easily digested and absorbed, which means it can be utilised by the body quickly. It also offers a bigger insulin boost, meaning that more fuel/energy is sent to your muscles.

Whey protein is usually made from cows milk, however, this is not suitable for use by vegetarians and vegans. Luckily, there are other options available for them including pea, hemp and soy protein powders.

Benefits of Whey Protein

Well, chances are the benefit you are most interested in is its ability to help improve muscle synthesis and to promote the growth of lean muscle mass 3.

This is not the only benefit on offer though, as whey protein has also been shown to help with weight loss, with one study showing that those who supplemented with whey lost more body fat than those who did not 4.

There is also promising research showing that it can help:

  • Fight cancer 5
  • Lower cholesterol 6
  • Improve asthma 7
  • Reduce the risk of heart disease and stroke 8

Potential Side Effects of Whey Protein

While there are plenty of benefits to be gained from whey protein, there is a potential risk of side effects.

Most of the time these side effects occur due to the user being lactose intolerant.

If you are lactose intolerant it means that you may encounter digestive issues such as bloating, gas, stomach cramps and diarrhoea 9.

Lactose intolerance may also cause constipation, which slows down the movement of your gut 10.

Lactose is the main carb found in whey protein, and if you are lactose intolerant your body will not produce enough lactase, which is an enzyme that helps to digest lactose.

If you suffer from this condition then my suggestion to you would be to choose an isolate rather than a concentrate. This is because the isolate is more refined, so contains less lactose.

You may also want to try a non-dairy alternative protein powder like soy, pea, egg, rice or hemp.

Some people may also be allergic to whey protein, and while allergies to cows milk is rare, with only 90% of people suffering from it, most people will outgrow the allergy by the age of 3 11.

If you have an allergy to cows milk, drinking a protein shake may cause one of the following side effects:

  • Hives
  • Skin rash
  • Facial swelling
  • Throat and tongue swelling
  • Runny, or stuffed nose

An allergy to cows milk may also trigger anaphylaxis, which is a life-threatening allergic reaction.

It is often believed that whey protein can damage your kidneys, but this is not true. There is plenty of research available that shows that this information is false 12 13 12.

However, what is clear from scientific studies is that a diet that contains too much protein can cause damage to those who already suffer from kidney disease 14 15.

It is also believed that damage can occur to your liver, but again there is research available that debunks this theory 16.

Another common belief is that protein can cause osteoporosis, which is a disease characterised by weak bones. However, recent research has found the opposite to be true, that eating more protein was beneficial to bone strength 17 18 19.

Whey Protein FAQs

The following are commonly asked questions about whey protein (if you have any of your own questions please use the comment form provided below this guide):

Is Whey Protein Necessary?

No, you do not need to consume protein shakes to build muscle. At the end of the day, they are just a supplement.

If you are consuming enough protein from your diet alone then you most certainly do not need to drink them.

Will Whey Protein Go Bad?

The supplement you have bought will have an expiry date printed on it.

This does not necessarily mean that the whey will go bad overnight, and it may take weeks or even months to do so.

We cannot say for certain how long after the expiry you should stop using it.

Is it OK to Drink Protein Shakes Without Working Out?

While it is ok to drink protein shakes without having worked out, you should remember that the reason why we would usually drink them is to repair the damaged muscle fibres that occur after exercise.

Protein shakes are naturally high in calories so you will likely see weight (fat) gain, as these calories are not used up.

Can Whey Protein Be Taken With Water?

Yes, of course. Most people would choose to mix protein shakes with either milk or water.

Will Whey Protein Cause Diarrhoea?

For some people, whey protein may cause diarrhoea and other digestive issues, for instance bloating, gas and stomach cramps.

Can You Drink Protein Shakes On Rest Days?

Yes, you should aim to get your required protein intake whether you have worked out or not.

Are Whey Protein Shakes Keto?

You should choose one that has a few carbs.

Is Whey Protein Steroids?

No, don’t be silly!

Can Whey Protein Cause Acne?

Research had suggested that it can cause acne breakouts 20 21. This is because of the amino acids that it contains.

These amino acids can lead to hormonal changes. Also, as whey protein is usually made from dairy this can lead to an increase in sebum, or oil production, which also increases the risk of breakouts.

Is It Bad To Drink 2 Protein Shakes A Day?

No, but you must remember protein shakes should be used to supplement your diet not replace it.

What Whey Protein Is Best For Diabetics?

I would recommend isolate or hydrolysate varieties if you are diabetic. Whey protein concentrate contains too much lactose.

Research has found that high protein diets can be beneficial for diabetics 22 23, offering various benefits that include the ability to manage blood sugar levels and weight loss.

Should I Drink Whey Protein Before Bed?

There is plenty of research available that shows the benefits of drinking a protein shake before bed.

These benefits include increased muscle growth 24, better recovery from exercise 25 and weight loss 26.

Drinking the wrong type of protein shake may disturb your sleep, however. You don’t want to consume one that gives you an energy boost just before bed.

It is best to choose a slowly digested protein as this will offer the benefits without disrupting your sleep patterns.

Can Whey Protein Make You Gain Weight?

Yes, whey protein can help you to gain weight or lose weight.

Depending on your goals you will need to change both your diet and exercise habits too.

Will Whey Protein Cause Gout?

Too much protein can put extra strain onto your liver and kidneys. This can cause an increase in uric acid levels, which may increase the risk of a gout flare-up.

Plant-based protein will be a better option if you suffer from gout and wish to supplement your protein intake.

Can Whey Protein Cause Cancer?

Research has found that whey protein may be able to treat cancer 5, although more research is needed.

Can Whey Protein Be Taken With Milk?

Yes, you can make protein shakes with milk or with water.

Using milk will slow down the digestive process and will also add calories, making it more suitable for those looking to bulk up.

What Whey Protein Is Safe During Pregnancy?

As long as you are not exceeding your recommended protein intake then whey protein should be safe to use during pregnancy.

If you are already eating cheese or other dairy products then you are in theory already consuming whey.

I would advise that you talk to your doctor or a health professional if you are unsure.

Can Whey Protein Increase Height?

Firstly, you need to ask yourself one question. How old are you?

If you are over the age of 21 then chances are you are done growing, and nothing will help. Apart from painful surgery.

If you are younger then protein can certainly help with your growth 27, therefore whey protein may help to increase your height if you are younger.

Will Whey Protein Spike Insulin?

Yes, it will cause a spike in your insulin levels.

Can Whey Protein Cause Gas?

As stated previously, whey can potentially cause digestive issues, which may include gas.

Can Whey Protein Damage Kidneys?

If you have a healthy kidney then consuming a normal amount of protein will not cause any harm.

However, if you have kidney disease or if you consume excessive amounts of protein than you may cause damage to kidneys and to your renal function 12.

What Whey Protein Did Arnold Use?

It is believed that Arnold Schwarzenegger and many other bodybuilders of the time would use Rheo Blair Protein 28, which was a mixture of milk and egg protein.

This is despite being sponsored by Weider, who had their own supplement range available.

Can Whey Protein Be Used As Meal Replacement?

Yes, in theory, you can use a protein shake as a meal replacement. However, personally, I am not a fan of skipping meals.

If weight loss is your goal then I would suggest reading the following article.

Will Whey Protein Cause Hair Loss?

Your hair is made from protein, so it makes sense that protein can help keep it healthy. There is plenty of research that shows the benefits of protein for hair health 29 30.

However, there is research available from the Belgravia Centre [34]31 that shows that certain protein shakes may raise blood testosterone levels, which may cause hair loss.

It is believed that some protein shakes may contain ingredients like growth hormones and creatine.

Which Whey Protein is the Best?

Although whey protein hydrolysate is the best option, for the general public the cost of buying this type is not worth the added benefits.

I would recommend opting for a good quality whey protein isolate because they are more cost-effective than the hydrolysate, but offer more benefits than concentrate. Plus have a higher percentage of protein, with lower amounts of fat and carbohydrates.

Our suggested brand would be Battle Ready Fuel. Their isolate contains 90% protein (28g of protein in each serving), with very little fat or carbs.

It comes in a delicious triple chocolate flavour and costs £29.99 ($44.99) for a 900g tub.

Each order comes with FREE shipping and a full 100% money-back guarantee. If for whatever reason you are not happy with the product, it can be returned within 60 days for a full refund.

  1. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005), retrieved from[]
  2. Dietary protein for athletes: from requirements to optimum adaptation, retrieved from[]
  3. The effects of protein supplements on muscle mass, strength, and aerobic and anaerobic power in healthy adults: a systematic review, retrieved from[]
  4. A whey-protein supplement increases fat loss and spares lean muscle in obese subjects, retrieved from[]
  5. Whey protein concentrate (WPC) and glutathione modulation in cancer treatment, retrieved from[][]
  6. Effects of whey protein isolate on body composition, lipids, insulin and glucose in overweight and obese individuals, retrieved from[]
  7. Effect of whey protein to modulate immune response in children with atopic asthma, retrieved from[]
  8. Whey beverages decrease blood pressure in prehypertensive and hypertensive young men and women, retrieved from[]
  9. Nutrients in Dairy and their Implications on Health and Disease, retrieved from[]
  10. Lactose intolerance: diagnosis, genetic, and clinical factors, retrieved from[]
  11. Frequency of cow's milk allergy in childhood, retrieved from[]
  12. Dietary protein intake and renal function, retrieved from[][][]
  13. Mechanisms of renal vasodilation and hyperfiltration during pregnancy, retrieved from[]
  14. The impact of protein intake on renal function decline in women with normal renal function or mild renal insufficiency, retrieved from[]
  15. New insights into protein intake and progression of renal disease, retrieved from[]
  16. High-Protein Weight Loss Diets and Purported Adverse Effects: Where is the Evidence? retrieved from[]
  17. Dietary protein and bone health: a systematic review and meta-analysis from the National Osteoporosis Foundation, retrieved from[]
  18. Effect of dietary protein supplements on calcium excretion in healthy older men and women, retrieved from[]
  19. Dietary protein and skeletal health: a review of recent human research, retrieved from[]
  20. Incidence of acne vulgaris in young adult users of protein-calorie supplements in the city of João Pessoa, retrieved from[]
  21. Whey protein precipitating moderate to severe acne flares in 5 teenaged athletes, retrieved from[]
  22. An increase in dietary protein improves the blood glucose response in persons with type 2 diabetes, retrieved from[]
  23. Glucose-lowering effect of whey protein depends upon clinical characteristics of patients with type 2 diabetes, retrieved from[]
  24. Protein Ingestion before Sleep Increases Overnight Muscle Protein Synthesis Rates in Healthy Older Men, retrieved from[]
  25. Protein Ingestion before Sleep Improves Postexercise Overnight Recovery, retrieved from[]
  26. Night-time consumption of protein or carbohydrate results in increased morning resting energy expenditure in active college-aged men, retrieved from[]
  27. Major correlates of male height, retrieved from[]
  29. Diet and hair loss: effects of nutrient deficiency and supplement use, retrieved from[]
  30. Effect of low-protein diet and its duration on hair composition, retrieved from[]
  31. Could Protein Shakes Increase Hair Loss? retrieved from[]
Article Name
The Ultimate Guide to Whey Protein: Benefits, Side Effects & FAQs
Our guide will show you what the benefits of whey protein are if there are any potential side effects and will show you which supplement is best for your goals.
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