Whey protein: A concentrated food, not a drug

What it is

Whey protein is obtained from milk during cheese making. It is a food: it serves to top up the protein intake of anyone who does not reach it through diet. The authorised claims for protein refer to maintenance and growth of muscle mass, always within a sufficient total intake.

At the counter it is almost never a safety problem but a problem of expectations: it does not build muscle on its own, you need to train and eat enough.

What it does

It provides amino acids, especially leucine, which muscle uses to repair itself:

It is a convenient way to add protein when meals fall short.
A serving of 20-30 g is enough after training; more does not give more muscle.
It does not replace complete meals or an exercise plan.

At the counter

When to recommend it

Adult training strength who does not reach their protein need with food
Older people with a poor appetite, assessed by their doctor or dietitian
Anyone who eats little animal protein and tolerates milk

When not to

Cow's milk protein allergy (not lactose): contraindicated
Advanced kidney disease: the protein amount is set by their nephrologist
As a meal replacement in children, pregnancy or unsupervised diets

What to say at the counter. First ask how much protein they already get from food. If they do not need it, the shake is just an expense. And if they are lactose intolerant, look at isolate or a plant option.

Warnings

Important MILK ALLERGY: whey contains milk proteins and can cause severe reactions. Lactose intolerance is a different thing and usually tolerates isolate.
Caution KIDNEY DISEASE: any rise in protein should be discussed first with their nephrologist.
Caution Some products add sugars, sweeteners or stimulants: read the label.
Worth knowing Independent analyses have found differences between what is labelled and the real content: prefer brands with quality controls.

Pharmacokinetics

Absorption: Fast: digested and absorbed within a couple of hours.
Distribution: Amino acids pass into blood and muscle.
Metabolism: Used or broken down like any dietary protein.
Elimination: The excess is eliminated as urea by the kidney.

Concentrate and isolate

Aspect	Whey concentrate	Whey isolate
Protein	Less concentrated	More concentrated
Lactose	A bit more	Very little
Price	Lower	Higher
For whom	Most people without lactose problems	Those who tolerate lactose poorly

There is no absolute "best": it depends on tolerance and budget.

Self-assessment

Three questions. When you check your answers you will see the explanation for each one.

Someone with a milk protein allergy asks about whey. What do you do? Explain that it is contraindicated Tell them it is the same as lactose Offer the isolate
What serving is enough after training? 100 g The more the better 20-30 g
What is needed besides protein to gain muscle? Taking more supplements Nothing else Training and eating enough

Training content. It does not replace the summary of product characteristics or clinical judgement.

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