Whey protein is one of the most effective and researched supplements for muscle recovery, strength, and overall health. This guide explains what it is, how it’s made, the differences between WPC and WPI, and how to choose the right option.
5 min read
While the name might sound technical, whey is a natural component of dairy. Milk is composed of two primary proteins: approximately 80% casein and 20% whey. During cheese production, enzymes are added to milk to separate the solids (curds) from the liquid (whey).
This liquid whey is then collected, filtered to remove non-protein components like excess fats and sugars, and spray-dried into the fine powder you see in your supplement tub. The final result is a "complete" protein, meaning it provides every essential amino acid your body cannot produce itself. This includes a high concentration of Branched-Chain Amino Acids (BCAAs) (leucine, isoleucine, and valine) which act as the primary triggers for muscle protein synthesis and protect against muscle breakdown during training.
At True Protein, we believe the quality of the source milk dictates the quality of the results. We source our whey exclusively from New Zealand grass-fed cows for three specific reasons:
Understanding the processing methods helps you choose the right product for your digestion and goals.
WPC is the most common and cost-effective form of whey. It is filtered to concentrate the protein while retaining small amounts of naturally occurring fats and carbohydrates, including lactose. Our True WPC 80 contains 80% protein by weight (23.9g per serve), offering a creamier texture and richer flavour that makes it a perfect all-rounder for general health.
WPI undergoes additional ultra-filtration to strip away almost all remaining fat and lactose. True WPI 90 is our most popular choice, delivering 90% protein by weight (27.2g per serve). Because the lactose is largely removed, it is the superior option for those with mild digestive sensitivities or those strictly managing a calorie deficit.
Hydrolysate is "pre-digested" protein, where enzymes have already broken down the protein chains into smaller peptides for rapid absorption. While used in medical or infant nutrition, it often has a bitter taste and offers no significant advantage over a high-quality WPI for the average gym-goer.
Both products are derived from the same NZ grass-fed source. Here is how they compare across the metrics that matter:
| Feature | True WPC 80 | True WPI 90 |
|---|---|---|
| Protein per 100g | ~80g | ~90g |
| Fat Content | Low | Trace |
| Lactose Content | Small amounts | Very low (suits sensitivity) |
| Best For | Active lifestyles, general health | Weight loss, max efficiency |
| Texture | Creamier, richer flavour | Lighter, cleaner profile |
| Cost | More affordable | Slightly higher |
Protein supplementation is a proven strategy to optimise muscle mass across all ages and fitness levels. A major review in the British Journal of Sports Medicine found that protein supplementation significantly boosts muscle mass and strength gains during resistance training. This is largely due to leucine, an amino acid in whey that activates the mTOR pathway, the biological "on switch" for muscle building. Research shows that combining protein with strength training can increase your one-rep max by up to 9%.
Whey is a powerful tool for body composition. It has the highest thermic effect of any macronutrient, meaning your body burns 25–30% of its calories just to digest it. Additionally, whey increases satiety (the feeling of fullness), which helps reduce overall calorie intake throughout the day. Over time, as you build lean muscle, your resting metabolic rate (RMR) increases, allowing you to burn more energy even at rest.
Training causes microtrauma, tiny tears in your muscle fibres. Consuming whey within 1–2 hours of a session provides the immediate amino acids required to repair this tissue and grow back stronger.
Don't be fooled by flashy labels. Use this expert checklist to evaluate any product:
Is whey protein suitable for lactose intolerance?
Does whey protein cause bloating?
Can I use whey protein if I'm not an athlete?
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IMPORTANT INFORMATION: all content provided here is of a general nature only and is not a substitute for individualised professional medical advice, diagnosis or treatment and reliance should not be placed on it. For personalised medical or nutrition advice, please make an appointment with your doctor, dietitian or qualified healthcare professional.
