Amino Acids: The Complete Overview

Creatine, BCAAs, EAAs, L-theanine, taurine – the shelf of amino acid supplements can feel like a crash course in jargon. Yet behind it all sits a surprisingly simple idea. Short and to the point: amino acids are the building blocks of proteins. There are 20 protein-forming amino acids, 9 of them essential, meaning your body cannot make them itself. For individual amino acids, the EU has approved hardly any claims – the key exception is protein as a whole nutrient. This overview brings order to the field, explains EAAs and BCAAs, places the best-known individual amino acids in neutral context and points you to every in-depth guide.

The Key Points at a Glance

• 20 protein-forming amino acids – 9 of them essential (they have to come from food).
• EAA = all 9 essential amino acids, BCAA = the three branched-chain ones (leucine, isoleucine, valine).
• For individual amino acids there are hardly any approved claims – the exception is protein.
• Well-known individual forms: creatine, taurine, L-theanine, L-arginine, citrulline, L-carnitine, beta-alanine, L-tryptophan.
• We describe these individual substances neutrally: what they are, where they come from, what to look for in terms of form and quality.

What Amino Acids Do in the Body

When you eat protein, your body breaks it back down into its amino acids in the digestive tract and reassembles them – into exactly the proteins it currently needs. From this "construction kit" it builds muscle fibres, enzymes, transport proteins, parts of the immune system and precursors of signalling molecules (serotonin from tryptophan, for example). To do this, the body maintains a constant amino acid pool. If a single essential amino acid is missing, it can slow down protein synthesis – which is why people talk about the "quality" of a protein source: how well its amino acid pattern matches human needs. Animal sources usually cover it completely, while plant sources score in combination (grains plus legumes, for instance).

Essential, Non-Essential and Semi-Essential

The classification follows a single question: can the body make the amino acid itself?

• Essential (9 in total, including leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine): must come from food.
• Non-essential: the body can make these itself from other building blocks.
• Semi-essential (e.g. arginine, glutamine): in principle the body can make them, but in certain life stages or under heavy demand they may be needed on top.

If you want to keep an eye on your total protein intake, Protein Powder: How to Spot Quality and Whey vs. Pea Protein offer guidance. For a plant-based diet, cleverly combining sources is decisive – see Nutrients for Vegans and Nutrients for Vegetarians.

Protein: The Only Clearly Approved Claim

Unlike with vitamins, most individual amino acids have no specific approved health claims. The key exception is protein as a whole nutrient: protein contributes to a growth in muscle mass, contributes to the maintenance of muscle mass and contributes to the maintenance of normal bones (approved wording). This is why protein is so much in focus for physically active people, for building muscle and for preserving muscle with age. For a deeper look: Nutrients for Strength Training & Muscle Building and Nutrients for Recovery After Exercise.

Well-Known Individual Amino Acids – in Neutral Context

Many individual amino acids are taken in a targeted way, above all in the sport and wellness context. Since no health claims are approved for them, we describe them factually – what they are chemically, where they come from, what forms exist:

• Creatine – a substance the body makes from three amino acids, and one of the most-studied compounds in strength training: Creatine: How to Take It and Monohydrate vs. HCl.
• Taurine – occurs naturally in many tissues: Taurine: Context & Intake.
• L-theanine – an amino acid from green tea: L-Theanine: Context & Intake.
• L-arginine & citrulline – closely linked in metabolism: L-Arginine and Citrulline.
• L-carnitine – formed from two amino acids: L-Carnitine: Context & Intake.
• Beta-alanine – common in endurance and strength sports: Beta-Alanine: Context & Intake.
• L-tryptophan – a precursor of important signalling molecules: L-Tryptophan: Context.

What Research Is Looking Into

The fundamental role of amino acids as building blocks of proteins and of the body's own substances is well-established textbook knowledge. For protein as a whole nutrient, the claims relating to muscle mass and bones are so well evidenced that they are EU-approved. Beyond that, research examines individual amino acids in various contexts, especially around sport, muscle metabolism and recovery; creatine is among the most frequently studied individual compounds of all. For the individual amino acids mentioned here, no health claims are currently approved in the EU – we describe them neutrally. Much of this is the subject of ongoing studies and not a product effect. In case of persistent symptoms or when taking medication, the rule is: seek medical advice.

BCAAs, EAAs or Complete Protein – What Makes Sense?

A question that keeps coming up in the sport context: are BCAAs enough, or do you need EAAs, or straight away a complete protein? A simple line of reasoning helps here. BCAAs supply only three of the nine essential amino acids. EAAs cover all nine that the body absolutely needs for protein synthesis. A complete protein (whey, say, or a well-thought-out plant-based blend) additionally supplies the non-essential building blocks and other nutrients too – and it is the only one of the three that carries the approved claim on muscle mass and bones. For most people, therefore, the simple order is: first, enough total protein from your diet and, if needed, protein powder, and only then think about individual fractions. Once you have covered the basics, you have laid the foundation; isolated BCAAs or EAAs are more of a fine-tuning tool for specific situations than the first step.

Form, Timing and Quality

With amino acid products, the same scrutinising eye pays off as anywhere else: is the form clearly declared? What about the dosage? Are there unnecessary additives? Guidance comes from Reading the Label Correctly, Spotting Additives & Fillers and Lab-Tested: What Does It Mean? Whether something is taken around training or independently of it depends on the substance – Supplements Before or After Exercise sets a framework.

Where Amino Acids Come From: Food First

By far the most important source is perfectly ordinary protein from your diet. Animal foods such as meat, fish, eggs and dairy supply the complete pattern of essential amino acids. Plant sources such as legumes, grains, nuts and soy products score in combination – classically beans with rice or lentils with bread, because the profiles complement one another. Once you meet your total needs through diet, you have laid the foundation; individual amino acid supplements are then a targeted addition for particular goals. Guidance on this comes from Nutrients for Recreational Athletes and Nutrients for Occasional Exercisers.

Complete vs. Incomplete Protein Sources

One term that keeps coming up is the "completeness" of a protein source: whether it supplies all nine essential amino acids in sufficient amounts. Egg, milk, meat and fish are considered complete. Many individual plant sources are short on one or two amino acids – grains on lysine, for instance, legumes on methionine. The clever part: in combination they complement each other into a complete profile. This is why the blanket worry that a plant-based diet supplies "too few amino acids" is usually unfounded, as long as the sources are varied. More in The Difference Between Vegetarians & Vegans.

How Much Protein Does the Body Actually Need?

Because total protein intake is the decisive factor, it is worth looking at the amount. As a guide, the reference value for healthy adults is around 0.8 grams of protein per kilogram of body weight per day; anyone doing intensive strength or endurance sport, or wanting to preserve muscle with age, often orients towards the upper end or beyond. For a 70 kg person that is roughly 56 grams as a baseline. Alongside the amount, the distribution across the day is decisive: the body can support protein synthesis better when the protein arrives spread across several meals rather than bundled into a single one. Cover this basis – through diet and, if needed, protein powder – and you have done the most important thing for maintaining and building muscle; individual amino acid supplements are then the fine-tuning on top.

Who Individual Amino Acids Are of Interest To

It usually comes down to very concrete contexts: people who do strength training regularly are often interested in creatine or beta-alanine. People who do a lot of endurance training look at citrulline or L-carnitine. On a purely plant-based diet, overall protein quality comes into focus rather than the individual amino acid. These are descriptive use contexts – who does what – not promises of effect.

An Honest Assessment

The honest summary: amino acids are fundamentally important – but the decisive factor for most people is a sufficient total protein intake, not the individual powder. For protein there are clear, approved claims on muscle mass and bones; for individual amino acids the evidence varies widely. Anyone supplementing in a targeted way is best off doing so with realistic expectations, one substance at a time, and with an eye on transparent declaration and lab testing.

Suitable Products from Scheunengut

You will find all the individual amino acids in the Amino Acids category. If you focus on building blocks and recovery during training, take a look at Sport & Fitness and Energy. All products are lab-tested and made in Germany.

Frequently Asked Questions (FAQ)

What is the difference between EAAs and BCAAs?

EAA stands for the nine essential amino acids, which the body cannot make itself and which have to come from food. BCAAs are a subset of these: the three branched-chain amino acids leucine, isoleucine and valine, used above all in the sport context.

Which amino acid claim is approved in the EU?

For most individual amino acids there are no specific approved health claims. The key exception is protein as a whole nutrient: it contributes to the growth and maintenance of muscle mass as well as to the maintenance of normal bones.

Do I need amino acid supplements, or is protein from food enough?

For most people, a sufficient total protein intake is the decisive factor, not the individual powder. Perfectly ordinary protein from meat, fish, eggs, dairy or cleverly combined plant sources supplies the building blocks. Individual amino acids are a targeted addition for particular goals.

Does a plant-based diet supply enough amino acids?

Yes, as long as the sources are varied. Many individual plant sources are short on one or two amino acids – grains on lysine, for instance, legumes on methionine – but in combination they complement each other into a complete profile. Classic pairings are beans with rice or lentils with bread.