What is a pre-workout? Definition, composition and how to use it

You have almost certainly come across the term “pre-workout” on a colourful tub, or from a training partner. But what actually goes into one, and what is a pre-workout for? Here is a clear definition, with no jargon and no empty promises — so you know exactly what you are taking, and why.

So what is a pre-workout?

A pre-workout is a food supplement taken before a training session, usually as a powder to be mixed into water. Its job: to bring together, in a single serving, several ingredients that athletes use at the moment they train — stimulants, amino acids, amino acid derivatives.

The principle is simple. Rather than swallowing your caffeine, your citrulline and your beta-alanine separately, you gather everything into one glass, taken 20 to 30 minutes before training. So the question that really counts is not “does it contain well-known ingredients?” — most of them do. It is: does it contain the right ingredients, at the right doses, for YOU?

What is a pre-workout made of?

The composition varies enormously from one product to another. A few recurring families of ingredients do come back, though, and here they are, factually.

Caffeine

Caffeine is the headline ingredient in most pre-workouts. It is a central nervous system stimulant: it works by blocking adenosine receptors, adenosine being the molecule that builds up the feeling of tiredness across the day. On safety, ANSES considers that for a healthy adult it is prudent not to exceed 200 mg of caffeine in a single serving and 400 mg across the day (coffee, tea, soft drinks and supplements combined). Caffeine sensitivity is also highly individual.

Creatine

Creatine is one of the most studied supplements in sport. As for its effects, only one wording is recognised at European level: creatine increases physical performance in successive bursts of short-term, high intensity exercise (claim authorised by EU Regulation 432/2012, for an intake of at least 3 g per day).

Beta-alanine

Beta-alanine is an amino acid, a precursor of the carnosine found in muscle. Studies generally use doses in the region of 3 to 6 g per day. It can cause skin tingling (paraesthesia), a sensation with no seriousness to it.

L-citrulline

Citrulline (often as citrulline malate) is an amino acid involved in the nitric oxide pathway. In the literature it is frequently studied at doses of 6 to 8 g — whereas standard products often carry it at a “window-dressing” dose.

Other common ingredients

• Betaine (trimethylglycine): an amino acid derivative, most often studied at around 2,5 g per day.
• Tyrosine: an amino acid, precursor of certain neurotransmitters.
• Taurine: an amino acid naturally present in the body.
• Electrolytes (sodium, potassium, magnesium): minerals lost through sweat.

With these ingredients, keep one simple reflex: what counts is not their presence on the label, but the dose actually delivered, compared with the one used in the studies.

How do you use a pre-workout?

• When? 20 to 30 minutes before the session.
• How? Mix the serving into a large glass of water (250 to 400 ml).
• How much? Stick to the serving size. For caffeine, take into account everything you have already had during the day.
• What to avoid? Taking it too late: a caffeinated pre-workout can disrupt falling asleep.

A supplement replaces neither a balanced diet, nor sleep, nor structured training. It is added on top of solid foundations — not the other way round.

The real problem with the “standard” pre-workout

Most pre-workouts rest on the same model: a single recipe, designed to please as many people as possible. An average. And you are not an average. Three concrete problems:

• The same dose for everybody. A one-size format serves the same caffeine to a sensitive 55 kg person and to a habituated 95 kg one.
• “Window-dressing” under-dosing. Ingredients appear in amounts too small to match the studied doses.
• The hidden blend. The “proprietary blend” groups several ingredients under a shared total, without breaking down each dose.

The alternative: a formula designed for YOU

That is the MyNutriLab conviction: every athlete deserves their own formula. Rather than adapting your body to a fixed recipe, you build a formula that starts from you: your sport, your caffeine tolerance, your goals. Every dose known, down to the milligram, no hidden blend. As a French brand, we stand behind that transparency from end to end.

FAQ

What is a pre-workout for?

It brings together in a single serving, before training, ingredients used by athletes (caffeine, amino acids, derivatives). Its value depends directly on the ingredients it contains and on their doses: two pre-workouts can have almost nothing in common.

When should you take your pre-workout?

Generally 20 to 30 minutes before the session, mixed into a large glass of water. If it contains caffeine, avoid taking it too late and account for the coffee you have already had.

Does a pre-workout always contain caffeine?

No. Caffeine-free formulas exist, useful for evening training or for sensitive people. With a customisable formula, you simply set it to zero.

How much caffeine is reasonable?

For a healthy adult, ANSES considers it prudent not to exceed 200 mg per serving and 400 mg per day, from all sources combined. Since sensitivity varies from one person to the next, it is better to start cautiously.

👉 Build my formula — to the milligram, matched to your sport.