Sports nutrition is really the study of two things: giving muscle the raw material to rebuild after training, and giving the working cell a faster way to regenerate its fuel. Almost everything in this category does one job or the other. The protein powders supply amino acids for repair; the creatine, carnitine and citrulline act on the energy and blood-flow side. Our sports nutrition collection brings together whey and plant proteins, collagen peptides, creatine, and the single amino acids used around training.

Choosing a protein: whey, plant or collagen

These three are not interchangeable, because they are different proteins with different amino acid profiles.

• Whey concentrate (WPC) vs whey isolate (WPI) — both come from milk, and the difference is how far the filtration goes. Concentrate retains more of the milk fat and lactose along with the naturally occurring immune fractions; isolate is filtered further, leaving a higher protein percentage per scoop and very little lactose, which is why it tends to suit people who find dairy heavy. Whey is naturally rich in leucine, the amino acid that acts as the trigger signal for muscle protein synthesis rather than merely a building block.
• Plant proteins — pea isolate, brown rice and the multi-source raw blends. Individual plant proteins each run low in a particular amino acid: pea is modest in methionine, rice and most grains are modest in lysine. Blending them covers the gap, which is why the better plant formulas combine sources rather than using one. We also stock lysine and methionine as single aminos.
• Collagen peptides — worth understanding as connective-tissue protein, not muscle protein. Collagen is very high in glycine, proline and hydroxyproline and low in leucine, so it is used for tendons, ligaments, skin and joints rather than for driving muscle synthesis. See our Collagen range.

How creatine works — the phosphocreatine system

Creatine is one of the most heavily researched compounds in this category, and its mechanism is elegantly simple. A muscle contracting at full effort exhausts its stored ATP within seconds. Creatine is stored in muscle as phosphocreatine, which holds a spare phosphate group and donates it to spent ADP to rebuild ATP almost instantly. That is the entire effect: a larger phosphocreatine reserve means the cell can regenerate its immediate fuel for longer before it has to switch to slower energy pathways. Because the effect depends on saturating muscle stores, creatine is taken daily rather than only on training days, and plain creatine monohydrate remains the form the research is built on.

Citrulline, arginine and the nitric oxide pathway

Both amino acids appear in this collection and they reach the same destination by different routes. Nitric oxide, which relaxes blood vessel walls and supports blood flow to working muscle, is made from arginine. The complication is that oral arginine is substantially broken down by the enzyme arginase in the intestine and liver before it reaches the circulation. Citrulline avoids that first pass entirely and is converted to arginine in the kidneys, which is why citrulline malate has become the more common pre-training choice despite arginine being the direct precursor. It is a good example of why the form on the label matters more than the name of the pathway.

The supporting cast

• Glutamine — conditionally essential under heavy training load, and the preferred fuel of the cells lining the intestine, which is why it sits at the crossover between sports and gut support. See Digestion & Gut Health.
• Carnitine and acetyl-L-carnitine — carnitine is the shuttle that carries long-chain fatty acids across the mitochondrial membrane so they can be burned for energy; without it, fat cannot enter the furnace. See Energy.
• BCAAs — leucine, isoleucine and valine, the three branched-chain aminos, notable for being metabolised largely in muscle rather than the liver.
• Glycine and glucosamine — glycine is the most abundant amino acid in collagen and also a calming inhibitory neurotransmitter; glucosamine is a precursor for the glycosaminoglycans of cartilage. See Joint Health.

Who may benefit

People training regularly and wanting to support recovery and lean muscle, anyone whose daily protein intake falls short of their training load, and those supporting connective tissue and joints alongside their sport.

Frequently asked questions

Whey isolate or whey concentrate? Isolate is filtered further, giving more protein per scoop with minimal lactose; concentrate retains more of the milk fat, lactose and native fractions. Isolate generally suits those sensitive to lactose.
Does creatine need a loading phase? Loading saturates muscle stores faster, but a consistent daily dose reaches the same saturation point over a few weeks — the mechanism depends on the stores being full, not on how quickly you filled them.
Is plant protein as good as whey? A well-blended plant protein covers the amino acid profile well; the practical differences are leucine content and how the individual sources are combined.
Will collagen build muscle? Collagen supplies the amino acids of connective tissue rather than the leucine that signals muscle synthesis, so it complements a whey or plant protein rather than replacing it.

Related: Protein Powder · Amino Acids · Magnesium

Browse our full sports nutrition collection below. Always read the label and use only as directed. Supplements may only be of assistance if dietary intake is inadequate. If you are pregnant, breastfeeding, taking medication or have a kidney condition, consult your healthcare professional before use.