Three of the seven ingredients in GLP5 GLT are amino acids. This guide explains amino acid supplements in plain English: what L-arginine, L-glutamine and L-leucine are, which foods contain them and how they sit in a one-a-day capsule.
If you have just landed here and want the whole product first, the GLP5 GLT home page for the UK and Ireland shows the label and the ordering options. Below, we take the amino acids one by one, along with the guarana in the same capsule and its natural caffeine.
What are amino acids?
Proteins are built from smaller units called amino acids, a bit like a long wall built from individual bricks. When you eat a piece of fish, a bowl of lentils or an egg, your body breaks the protein down into amino acids and uses them again. There are around twenty amino acids in total, and some are called essential because the body cannot make them, so they must come from food.
A supplement amino acid is the same molecule, supplied in a pure form. In a capsule like GLP5 GLT the amounts are small, measured in milligrams, and the label lists each one.
| Ingredient | Per capsule | Type |
|---|---|---|
| L-arginine (hydrochloride) | 100 mg | Amino acid |
| L-glutamine | 50 mg | Amino acid |
| L-leucine | 50 mg | Amino acid (essential) |
The "L" in front of each name describes the shape of the molecule. It is the form found in food and in the body, so you do not need to worry about it beyond reading it on the label.
What is L-arginine?
L-arginine is an amino acid found in protein-rich foods. It is present in meat, poultry, fish, dairy, eggs, nuts and seeds, and in smaller amounts in whole grains and pulses. Think of a roast chicken, a piece of salmon, a handful of peanuts or the cheese in a jacket potato.
In GLP5 GLT it appears as L-arginine hydrochloride, often written HCl, which is a stable salt commonly used in food supplements. Each capsule provides 100 mg. L-arginine is described here for what it is, and no health claim is made for it.
What is L-glutamine?
L-glutamine is one of the most abundant amino acids in the body. It comes from protein foods such as beef, fish, eggs, dairy and tofu, and from some plant foods, including beans and cabbage. A bowl of Irish stew, a cheese omelette or a plate of cod and chips would each bring some.
Each GLP5 GLT capsule provides 50 mg. It is listed alongside the other amino acids and it carries no health claim.
What is L-leucine?
L-leucine is one of the nine essential amino acids, and one of the three branched-chain amino acids (often shortened to BCAAs), alongside isoleucine and valine. Because the body cannot make it, leucine has to come from food. Eggs, dairy, meat, fish, soya and pulses are all good sources.
Each capsule provides 50 mg. Again, leucine is described for what it is, with no health claim.
Which everyday foods contain these amino acids?
Most people in the UK and Ireland eat all three amino acids every day without thinking about it. The list below shows how common they are.
| Food | L-arginine | L-glutamine | L-leucine |
|---|---|---|---|
| Chicken, turkey, beef, lamb | yes | yes | yes |
| Fish, such as salmon, cod, mackerel | yes | yes | yes |
| Eggs | yes | yes | yes |
| Milk, cheese, yoghurt | yes | yes | yes |
| Nuts and seeds | yes | some | some |
| Lentils, beans, chickpeas | yes | some | yes |
| Oats and wholegrains | some | some | some |
So the amounts in a capsule are modest compared with what a normal dinner provides. The supplement is a small complement to the diet, not a replacement for it.
What is guarana, and where does the caffeine come from?
The same capsule contains 100 mg of guarana extract (Paullinia cupana). Guarana is a climbing plant native to the Amazon basin, and its seeds are used to make the extract. Guarana naturally contains caffeine, but the label does not state how much, so it is wise to treat it as one more source of caffeine in your day.
A few practical ways to keep track:
- Count the tea, coffee, cola and energy drinks you have already had.
- Take the capsule with lunch rather than late dinner if you are sensitive to caffeine.
- If you are pregnant or breastfeeding, GLP5 GLT is not recommended.
Three amino acids and four more ingredients, one capsule
See the GLP5 GLT offer Food supplement for adults 18+. Not a substitute for a varied, balanced diet and a healthy lifestyle. One capsule a day; do not exceed it.How do the three amino acids fit with the rest of the capsule?
GLP5 GLT has seven ingredients, in this order on the label: L-arginine, apple cider vinegar extract, guarana extract, L-glutamine, L-leucine, zinc and chromium. The two minerals are the only ones with authorised claims. You can read more about them in our zinc and chromium guide, and about the vinegar in the apple cider vinegar capsules guide.
The capsule shell is HPMC, with microcrystalline cellulose as a filler and E470b as an anti-caking agent. The full table is in the GLP5 GLT ingredients guide.
Are amino acid supplements the same as protein powder?
No. A protein powder, such as whey or pea protein, supplies many grams of protein a serving, and it contains all the amino acids bundled together. A capsule with three amino acids supplies milligrams, a thousand times less per unit. They have different purposes and different labels, which is why it is worth reading the line that gives the amount per capsule.
If you already use a protein powder, a protein bar or a sports drink, the amino acids in GLP5 GLT add only a small amount on top. The main thing to check is the zinc and caffeine in your other products.
How should I take a capsule with amino acids?
Take one capsule a day, whole, with plenty of water, around two large glasses. Do it 15 to 30 minutes before or during lunch or dinner, and do not exceed the daily serving. Step-by-step advice, including how to build the habit, is in our how to take GLP5 GLT guide.
Who should check first?
GLP5 GLT is for adults aged 18 and over. Speak to your GP or pharmacist first if you:
- take prescribed medication, especially for blood sugar,
- have a kidney, liver or other medical condition,
- are on a specialist or medically supervised diet,
- are pregnant, trying for a baby or breastfeeding.
A food supplement is not a substitute for a varied, balanced diet and a healthy lifestyle. Keep the pack closed in a cool, dry place, out of the reach of children. If the website and the pack differ, the pack applies.
Frequently asked questions
What are L-arginine, L-glutamine and L-leucine?
They are amino acids, the building blocks of protein. GLP5 GLT contains 100 mg of L-arginine (as hydrochloride), 50 mg of L-glutamine and 50 mg of L-leucine per capsule.
Which foods contain these amino acids?
Meat, fish, eggs, dairy, nuts, seeds, pulses and wholegrains all contain them. Most people in the UK and Ireland eat all three every day.
What does the L mean in L-arginine?
It describes the shape of the molecule. The L form is the one found in food and in the body, so you only need to read it on the label.
Is L-leucine an essential amino acid?
Yes. The body cannot make it, so leucine has to come from food. It is also one of the three branched-chain amino acids, along with isoleucine and valine.
Does GLP5 GLT contain caffeine?
Guarana naturally contains caffeine. The label shows 100 mg of guarana extract per capsule but no caffeine amount, so count it alongside your tea, coffee and fizzy drinks.
Are amino acid capsules the same as protein powder?
No. A protein powder supplies grams of protein per serving, while the three amino acids in a GLP5 GLT capsule are measured in milligrams.
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Last reviewed 20 October 2026. This guide is general information about a food supplement.