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Whey Protein 101: Everything You Need to Know

15th May 2025

15th May 2025

By Josh Makin

If you’re at all interested in health, fitness or nutrition, you’ve probably heard about whey protein. It’s one of the most commonly used sources of protein for supplements and it can offer a wide range of benefits to users. 

But let’s hit the brakes a second – what exactly is whey protein? And what are these supposed benefits? Let’s break it down. 

What is whey protein?

Whey protein is a high-quality protein source which comes from whey (no prizes for guessing that) – otherwise known as the watery stuff which separates from the curds when making cheese. Once separated, the whey is processed to remove lactose and other components we don’t need, leaving behind a concentrated whey protein which is then dried into a powder form.

Sounds a bit strange, granted, but it’s a real powerhouse.

Whey protein is a complete protein, meaning it contains all nine essential amino acids (the ones our bodies can’t make on their own). It’s also quickly absorbed by the body, making it a great choice for a post-workout refuel.

Benefits of whey protein

With comparisons out the way, what are the benefits of adding whey protein into your workout plan?

1. High nutritional value

Whey protein is widely considered the best form of protein supplement because of its superior nutritional profile. Not just a complete protein, whey typically contains more protein per serving and is absorbed by your gut much faster than other types of protein.

In short, you get more of the good stuff and you get it faster, too. Win-win.

2. Supports muscle growth and repair

Whey protein’s high protein content and broad suite of amino acids makes it perfect for both muscle repair and those looking for gains.

Whey contains a high concentration of the BCAA leucine, which is the primary amino acid involved in muscle growth. This makes it a great accompaniment to your workout routine.

Regular intake of whey protein has also been shown to help reduce inflammation throughout the body, which is a huge plus for recovery and general wellbeing.

3. Supports weight management and satiety

Whey isn’t just a great supplement for muscle growth, it can also be hugely beneficial for those trying to manage their weight. Whey protein has been shown to significantly reduce feelings of hunger, which can make it much easier to stay on track with a healthy diet.

For example, Innermost’s The Strong Protein contains just 147 calories for a 40g serving, making it an effective, delicious and convenient solution to keep on deck. 

4. Convenient and versatile

Speaking of convenience, it doesn’t really get more convenient than whey protein.

You can throw together a delicious, nutritious shake in seconds whether you’ve got your favourite milk on hand or just water. Or, if you’re feeling creative, head to the kitchen and bake with it (protein pancakes – yum), or mix it into oats, yoghurts and smoothies for some serious treats that taste and feel good.

Whether you’ve got time to cook up a storm or you’ve only got 30 seconds before you need to be out the door, whey protein makes nutrition easy.

How can whey protein support your fitness goals? 

Whey protein is a great supplement for a range of fitness goals. Let’s take a look at how.

If you’re trying to build muscle…

Whey alone won’t do the job – you’ve gotta put the work in. When you’re done sweating up a storm, take your whey right after your workout (as soon as possible but definitely within 60 minutes for maximum impact). 

Whey helps to repair muscles which are damaged during exercise as well as promoting growth to make you stronger for next time. You know what they say, no pain, no gain…

If you want to push your workouts even further with whey on hand to repair the damage, try pairing your protein shake with The Power Booster for an extra hit of power, strength and speed.

If you’re focused on fat loss…

Swap out the snacks for a whey protein shake to cut down on calories and keep you fuller for longer between meals. The high protein content of whey can also help to preserve muscle mass if you’re in a calorie deficit, which is another big plus. 

If you’re training for performance or endurance…

When you’re looking to perform at a high level or for an extended period of time, repetition is a key part of the process. However, with repetition comes aches, pains and inevitable recovery time.

Whey protein is a great recovery aid which can help to reduce muscle soreness and support your immune system while your body is undergoing physical stress.

Work whey into your diet and get back on the grind in no time.

How does whey compare to other proteins?

When you’re shopping around for the best protein, there are a lot of factors to consider. Let’s take a quick look at how whey protein stacks up against the competition.

Whey vs casein protein

Both whey and casein are derived from milk, with casein making up around 80% of the total protein content of milk.

The question here is: why isn’t casein seen as much on the shelves? 

There are a few reasons, one of the main ones being casein is absorbed by the body at a much slower rate. The amino acids in whey protein stay in your bloodstream for around 90 minutes until they’re absorbed, whereas casein amino acids can stay in your system for as long as five hours. If you’re looking for a quick hit, especially after a workout, whey is the way to go. 

The branched-chain amino acid (BCAA) profile of whey is also superior to casein, meaning it can be more effective at building muscle. 

Whey vs soy protein

Soy offers a good alternative option for many as it’s a plant-based source of protein which also contains all nine essential amino acids. While studies have shown little difference in muscle growth and strength development between soy and whey protein, there are other downsides to soy protein which whey doesn’t have.

Soy protein contains considerably less leucine and lysine than whey (the amino acids responsible for muscle growth and repair, blood sugar regulation and the production of hormones and energy), which can be a big turn off for many. 

As such, whey is widely considered a higher-quality protein source than soy, but soy protein typically comes with a smaller price tag, making it an appealing choice for many.

Whey vs pea & rice protein

Two other popular sources of protein are pea and rice protein. These are often used together, like in The Fit Protein or The Health Protein, to offer a balanced and well-rounded vegan protein option.

Both rice and pea protein contain all nine essential amino acids, albeit in a slightly lower density than whey. To put it plainly, whey retains its crown as the most complete protein source, but for those who can’t or don’t want to have whey, pea and rice protein offer a fantastic option.  

It’s the whey to go

When it comes to protein supplements, whey is widely considered to be the most complete form you can get your hands on – and for good reason. 

With a high concentration of protein per serving, broad range of amino acids and huge variety of ways to enjoy it, whey is an easy way to support your fitness goals, whatever they are.

If you can’t have whey, or maybe just don’t want to, check out our range of vegan supplements for some plant-based alternatives.  

We’ve shown you the whey (sorry), now go forth and conquer. 

References

  • Schoenfeld, B., Aragon, A. (2018) How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. Int Soc Sports Nutr. Click here.
  • Zhou, L., Xu, J., Qin, L. (2015) Effect of whey supplementation on circulating C-reactive protein: a meta-analysis of randomized controlled trials. Nutrients. 7(2). Click here.
  • King, N., Slater, G. (2015) The effect of a whey protein supplement dose on satiety and food intake in resistance training athletes. Appetite. Click here.
  • Schoenfeld, B., Aragon, A. (2007) Bovine milk in human nutrition – a review.  Lipids Health Dis. Click here.
  • Lynch, H., Buman, M. (2020) No Significant Differences in Muscle Growth and Strength Development When Consuming Soy and Whey Protein Supplements Matched for Leucine Following a 12 Week Resistance Training Program in Men and Women: A Randomized Trial. Int J Environ Res Public Health. Click here.

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Magnesium for Sleep: Here's What You Need to Know
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Key takeaways Magnesium supports several normal processes linked with rest, including muscle function, nervous system function and energy metabolism. Magnesium may help some people sleep better, particularly where poor sleep is connected to stress, low magnesium intake, muscle tension or poor recovery. Food should always be the foundation, but magnesium supplements can help support a consistent intake when busy lifestyles, training and irregular meals get in the way. Magnesium works best as part of a broader evening routine, alongside sensible caffeine timing, reduced evening stimulation, good nutrition and proper recovery. What is magnesium and why is it linked to sleep Magnesium is an essential mineral found in food, water and supplements that is involved in over 300 bodily processes. It acts as a mandatory helper molecule (coenzyme) for your cells. Some of the key biological functions of magnesium include: Supports energy production by helping the body convert food into usable cellular energy. Contributes to normal muscle function, including the balance between muscle contraction and relaxation. Supports normal nervous system function by helping regulate nerve signalling and neurotransmitter activity. Contributes to normal bone structure, with a significant proportion of the body’s magnesium stored in bone. Supports normal glucose metabolism, with magnesium involved in blood glucose control and insulin-related processes. While by no means an exhaustive list, this gives a wider sense of how widely it is used throughout the body. Magnesium’s connection with sleep comes from the way it supports systems involved in relaxation and recovery. As highlighted, magnesium helps regulate nerve signalling and muscle contraction, which is one reason it is often associated with calmness, reduced tension and post-training recovery. It is also commonly discussed in relation to GABA (or gamma-aminobutyric acid), a neurotransmitter involved in calming nervous system activity. While the relationship between magnesium and sleep is still being studied, the general theory is that healthy magnesium levels may help the body and brain shift away from a heightened, alert state and towards a more relaxed one. This matters because good sleep rarely begins the moment you get into bed. It starts earlier, as your body and mind begin to downshift. For active, busy people, this can be one of the hardest parts of the day. If your evening routine looks like finishing work, replying to messages, doing a late workout, eating quickly and then expecting your brain to instantly power down, you are asking a lot from your body. Magnesium may support the relaxation side of that process, but it works best when the rest of your routine is helping too. Does magnesium help you sleep? Magnesium may help some people sleep better, but it is not a guaranteed solution for everyone. Its value sits more in supporting the body’s normal relaxation and recovery processes than acting like a direct sleep aid. A 2021 systematic review and meta-analysis published in BMC Complementary Medicine and Therapies looked at oral magnesium supplementation for insomnia in older adults. It found that magnesium may help reduce the time it takes to fall asleep. While the results were promising, the sample size was limited. Magnesium is most likely to be helpful when poor sleep is linked to factors such as low magnesium intake, stress, muscle tension, a busy nervous system or poor recovery. Someone who trains several times a week, works long days and struggles to wind down at night may find it more beneficial for sleep specifically than someone whose sleep issue is caused by an untreated medical condition, severe anxiety, chronic insomnia or an inconsistent sleep schedule. It is also worth remembering that “better sleep” can mean different things to different people. Some people want to fall asleep faster. Others wake up during the night. Some sleep for eight hours but still wake feeling flat.  Magnesium is usually discussed in relation to relaxation and sleep onset, rather than acting as a powerful sleep aid that forces deeper or longer sleep. A helpful way to think about it is this: magnesium supports the conditions that may make good sleep more likely. It does not replace the foundations of sleep itself (many of which we have discussed before). Can You Get Magnesium from Food? Yes, and this is a good place to start. Magnesium is found in a range of everyday foods, including: leafy green vegetables, nuts, seeds, legumes, wholegrains and dark chocolate. Pumpkin seeds, almonds, spinach, black beans and wholegrain products are all useful sources. Food Why it helps Pumpkin seeds Naturally rich in magnesium and easy to add to meals or snacks Almonds and cashews Useful sources of magnesium, healthy fats and plant-based protein Spinach and leafy greens Provide magnesium alongside fibre and other micronutrients Black beans and lentils Support magnesium intake while also adding fibre and slow-release carbohydrates Wholegrains A practical everyday source of magnesium and sustained energy Dark chocolate Contains magnesium, although best enjoyed as part of a balanced diet   A food-first approach also supports the bigger picture. Your body does not experience nutrients in isolation. A diet rich in magnesium-containing foods is often also higher in fibre, plant compounds and other micronutrients that support overall wellbeing. That said, busy lives do not always make consistent nutrition easy. Active people may also pay closer attention to magnesium because of its role in muscle function, energy metabolism and recovery. If you train regularly, sweat heavily, experience muscle tension or find yourself relying on convenience meals during busy weeks, your magnesium intake may be worth looking at. This is where effective supplementation can help, especially when it forms part of a wider routine rather than replacing a balanced diet. Where magnesium supplements can help Food should always be the foundation, but supplements can make magnesium intake easier to manage when life is busy. Rather than trying to rebuild your diet overnight, the right supplement can help you add consistent support around the routines you already have: morning training, post-workout recovery, evening wind-downs, or busy workdays where meals are not always as balanced as you would like. With Innermost, magnesium is included as part of wider, goal-led formulations rather than as a standalone quick fix. The Fit Protein contains 250mg of magnesium per serving, alongside vegan protein, maca, rhodiola root, cocomineral and Pink Himalayan sea salt, making it well suited to active lifestyles where performance, energy and recovery all matter. The Strong Protein contains 200mg of magnesium per serving, alongside protein, casein, creatine monohydrate, Montmorency cherries and bilberries. This makes magnesium part of a broader strength and recovery blend, supporting people who train regularly and want their nutrition to work harder around their goals. For evening recovery, The Recover Capsules are another good supplementation option, with magnesium included as part of a wider recovery-focused formula. This makes them a natural fit for people who want to support recovery at the end of the day, particularly when sleep, training and overall performance are closely connected. When should you take magnesium for sleep? Magnesium works best when it becomes part of a routine you can actually stick to. Because magnesium supports relaxation and recovery rather than acting as a sedative, timing does not need to be overly complicated. The most effective approach is usually the one you can repeat consistently. For many people, magnesium fits naturally into the evening. That might mean taking it with dinner, after training, or as part of a wider wind-down routine before bed. The aim is not to wait until you feel wired and then expect magnesium to force sleep. It is to give your body steady support at the point in the day when you want to start slowing down. This is particularly relevant if your days are busy or training-focused. When your body has been under physical or mental demand, sleep is part of the recovery process. Magnesium can support that bigger picture by contributing to normal muscle function, nervous system function and energy metabolism. Final thoughts: magnesium, sleep and recovery Magnesium has earned its place in the sleep conversation, but it deserves to be understood properly. It is an essential mineral with important roles in muscle function, nervous system function and recovery. For some people, particularly those who are active, stressed, low in magnesium-rich foods or struggling to wind down at night, supplementation may be a useful addition to an evening routine. The key is to keep expectations realistic. Magnesium is not a shortcut to perfect sleep. It is a supportive tool that works best alongside consistent habits: sensible caffeine timing, less evening stimulation, good nutrition, proper recovery and a calm bedtime routine. For Innermost, the bigger point is that form matters, but formulation matters too. Magnesium works best when it fits into a wider routine. That might mean supporting your intake through a recovery-focused product, taking supplements with food, and using them consistently rather than expecting an instant effect. References  Magnesium. National Institute for Health Professionals. Click here. Jewett, E., Sharma, S (2023). Physiology, GABA. National Library of Medicine. Click here. Mah, J., Pitre, T (2021).Oral magnesium supplementation for insomnia in older adults: a Systematic Review & Meta-Analysis. BMC Complementary Medicine and Therapies. Click here. Read more
Fibre
Within the fitness space there can be a tendency to think of fibre as something that’s just functional. Important, of course, but often its impact is only framed around digestion. In reality, fibre plays a far broader role in how your body performs and how you feel day to day, influencing variables like energy stability and appetite regulation through to long-term metabolic health. For anyone already investing in their training, recovery, and overall wellbeing, a high fibre diet matters more than you might think. It’s one of the simplest ways to bring more consistency to your nutrition, without adding complexity. In this guide, we’ll take a closer look at what fibre does, why it matters, and how to build a high fibre diet in a way that fits naturally into your routine. What is fibre and why it matters Fibre is a type of carbohydrate that is naturally sourced from foods like wholegrains, beans, nuts and more. At its core, dietary fibre is the part of plant foods your body can’t fully digest. Rather than being absorbed, it moves through the digestive system, interacting with everything along the way. This process is what makes fibre so valuable. It slows digestion, supports beneficial gut bacteria, and helps regulate how nutrients enter the bloodstream. Over time, these effects compound, influencing energy levels, hunger signals, and metabolic health. It’s worth understanding that fibre isn’t one single thing, and while it is often grouped together, different types have different roles. Broadly, fibre falls into two categories: Soluble fibre: This dissolves in water and forms a gel-like substance, helping to slow digestion and regulate blood sugar and cholesterol. Insoluble fibre: This adds bulk and supports regular movement through the digestive system. Most whole foods contain a combination of both, which is why variety matters more than focusing on a single source. Why intake is often lower than expected You might read this and think you’re easily hitting your daily fibre requirements. Yet, even among people who eat relatively well, fibre intake tends to fall short. In the UK, the recommendation sits at around 30g per day, yet average intake is closer to 18–20g. This isn’t usually down to poor habits. More often, it reflects modern eating patterns: A strong focus on high-protein meals can reduce the variety of plant foods in a diet, lowering fibre intake over time. A reliance on staples like white bread and pasta contain less fibre than wholegrain alternatives, making fibre intake harder to reach. Quick, convenient meals often lack the whole ingredients needed to support adequate fibre intake. The result isn’t a complete absence of fibre, but it does lead to a gradual shortfall below the 30g recommendations. Each meal might seem balanced in isolation, but across a full day or week, intake consistently sits below where it needs to be. The Key Benefits of a High Fibre Diet  A high fibre diet supports several key areas of health at the same time: Gut health and microbiome support As previously mentioned, fibre’s most recognised role is in digestion, but its impact actually goes deeper than that. Certain fibres act as prebiotics, feeding beneficial gut bacteria. These bacteria produce compounds known as short-chain fatty acids (SCFAs), including butyrate, which plays a role in maintaining the integrity of the gut lining and regulating inflammation. A 2019 review published in The Lancet found that higher dietary fibre intake was consistently associated with improved gut health markers and reduced risk of several chronic conditions. The key takeaway wasn’t a single “superfood”, but the cumulative effect of consistent fibre intake over time. There’s also increasing interest in how microbiome diversity influences overall health. A more varied intake of fibre tends to support a more diverse gut environment, which is linked to better resilience and function. For those looking to improve their training routines and hit new PBs, a well-functioning gut is central to recovery. This is because fibre supports the gut environment, which in turn affects how efficiently nutrients are absorbed. More stable energy levels When it comes to your energy, it isn’t just about calorie intake. It’s also key to ensure your body can effectively process these calories. This is where fibre can be highly beneficial. This is because fibre slows the digestion of other carbohydrates, leading to a more gradual release of glucose into the bloodstream. This helps avoid the sharp spikes and dips that can come from highly refined meals. Studies also show that diets higher in fibre are associated with improved glycaemic control, even in otherwise healthy individuals. In practical terms, this often leads to: More consistent energy across the day Fewer mid-afternoon crashes Reduced reliance on quick fixes like sugar or caffeine For those balancing work, training, and recovery, the more stable blood sugar levels provided by fibre mean more consistent energy availability. This can translate into better training sessions, particularly for longer or more demanding workouts. Appetite regulation High fibre foods tend to be more filling due to their volume and slower digestion. At the same time, they influence hormones involved in hunger and fullness, including ghrelin and peptide YY. There’s also a hormonal aspect to this. Fibre-rich foods can influence the release of satiety hormones, helping your body better recognise when it’s full. This creates a more sustainable approach to body composition. Instead of relying on weight loss restriction, your diet supports appetite regulation more naturally. Heart Health and Long-Term Outcomes In addition to the shorter-term health and wellness benefits, fibre intake also has a beneficial impact on long-term health. Soluble fibre, in particular, has been shown to help reduce LDL cholesterol by binding to cholesterol in the digestive system and aiding its removal. Large cohort studies have consistently linked higher fibre intake with a reduced risk of cardiovascular disease and type 2 diabetes. This is partly due to improved blood sugar regulation and partly due to the broader metabolic benefits of a fibre-rich diet. One study in particular by the BMJ found that each additional 7g of fibre per day was associated with a 9% reduction in cardiovascular disease risk. These outcomes aren’t immediate, but they reinforce the role of fibre as a long-term investment in health. High Fibre Diet Foods We’ve written about his previously (see here for our guide on high fibre foods) but in short, building a high fibre lifestyle doesn’t require a complete overhaul of your current diet. It’s instead about increasing variety and making more intentional choices within your existing routine. Below we have outlined some key foods that can help increase fibre intake. Whole grains Oats, brown rice, quinoa, and wholegrain bread provide a steady source of fibre while supporting sustained energy. They’re an easy upgrade from refined grains and tend to be more filling. Fruits and vegetables Eating more fruit and vegetable is one of the simplest ways to raise fibre intake. A useful approach is to focus on variety: Berries and apples for convenience Leafy greens for micronutrient density Root vegetables for more substantial meals Legumes Lentils, chickpeas, and beans are among the most fibre-dense foods available. They also provide plant-based protein, making them particularly useful in meals focused on satiety and recovery. Nuts and Seeds Chia seeds, flaxseeds, and almonds offer a concentrated source of fibre and can be added easily to meals. Even small additions, such as a tablespoon of seeds in a breakfast or smoothie, can make a difference over time. A Smarter Way to Think About Fibre Fibre doesn’t need to be treated as a standalone goal. It works best as part of a balanced, well-structured approach to nutrition - one that supports how you feel day to day, not just how you perform in the odd moment. For most people, that starts with whole foods. Building meals around plant variety, whole grains, and consistent habits. From there, the role of supplementation becomes more effective. The Innermost approach reflects that balance. Products like The Greens Blend can help support daily plant intake and micronutrients, while products such as The Lean Protein fit alongside a diet that prioritises both protein and fibre, rather than one at the expense of the other. Building a high fibre diet isn’t about adding or overhauling, instead It’s about making those small adjustments that bring more consistency to your routine. Over time, those shifts tend to have the biggest impact - not just on digestion, but on how your body feels, performs, and recovers. References Renolds, A., Mann, J., Cummings, J., Winter, N., MDiet, E., Morenga, L. (2019). Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. The Lancet. 393 (10170), 434-445. Click here.  NHS UK. How to get more fibre into your diet. Click here.  Hullings, A., Sinha, R., Liao, L., Freedman, N., Graubard, B., Loftfield, E. (2020). Whole grain and dietary fiber intake and risk of colorectal cancer in the NIH-AARP Diet and Health Study cohort. The American Journal of Clinical Nutrition. 112 (3), 603-612. Click here. Threapleton, D., Greenwood, D., Evans, C., Cleghorn, C., Nykjaer, C., Woodhead, C., Cade, J., Gale, C., Burley, V. (2013). Dietary fibre intake and risk of cardiovascular disease: systematic review and meta-analysis. BMJ.347. Click here. Read more