# Do you need a leucine supplement?

Source: https://www.healthnews24.co.za/answers/leucine-supplement-do-you-need-it/
Publisher: Healthnews24 (South Africa's supplement answer desk)
Updated: 2026-10-27

> Almost certainly not. Muscle protein synthesis is maximised with roughly 2–3 g of leucine per meal (ISSN range 700–3 000 mg), and a 25 g scoop of whey already provides about 2.5–3 g. Older adults and plant-based eaters are the groups that can fall short, but a bigger protein serving usually fixes it for less money in South Africa.

Key facts:
- ISSN: 700–3 000 mg of leucine per protein dose; about 2–3 g in practice for young adults and about 3 g for older adults.
- Whey is roughly 10–11% leucine, so 25 g of whey gives about 2.5–3 g.
- Plant proteins are lower in leucine; servings of about 30–40 g or blends help reach 2–3 g.
- NPL Platinum Whey Plus 1 kg costs R23.52 per 30 g of protein at the NPL shop (October 2026).

## Do you need a leucine supplement?

No, for most people. Leucine is the amino acid that most strongly switches on muscle protein synthesis (via mTOR). Meals need enough leucine, plus all the other essential amino acids, to get the full response. The ISSN suggests 700–3 000 mg of leucine per protein dose, and in practice about 2–3 g for young adults and about 3 g for older adults.

## How much leucine do common proteins give?

Whey is typically about 10–11% leucine by protein weight (it varies by product). That gives these approximate figures:

| Whey protein per serving | Approx. leucine |
|---|---|
| 20 g | 2.0–2.2 g |
| 25 g | 2.5–2.8 g |
| 30 g | 3.0–3.3 g |
| 40 g | 4.0–4.4 g |

A typical South African whey scoop supplies about 20–27 g of protein, depending on the product, so one scoop usually reaches the threshold. Meat, fish, eggs and dairy do the same at a normal meal.

## Who might fall short?

- **Older adults.** They need more leucine per meal because of anabolic resistance. A larger protein serving is the first fix. See [how much protein older adults need](/answers/how-much-protein-do-older-adults-need/).
- **Plant-based eaters.** Most plant proteins are lower in leucine. The evidence suggests servings of about 30–40 g, or pea-rice blends, to reach 2–3 g of leucine. Faithful to Nature's Pea Protein Isolate 650 g (R148–R185) costs about R28.46 per 100 g of powder, and USN BlueLab Plant Protein 900 g (R399–R474.99) is about R52.78 per 100 g.
- **Dieters** eating small, low-protein meals.

## Does adding free leucine help?

Not on its own. Adding leucine to a low-protein meal does not fix it, because the other essential amino acids are still missing. Free leucine can also confuse label maths, because added amino acids can inflate a product's apparent protein; see [what is amino spiking](/answers/what-is-amino-spiking-whey-south-africa/).

## What is the cheapest way to get leucine?

Protein. NPL Platinum Whey Plus 1 kg (R490 at the NPL shop) costs R23.52 per 30 g of protein, which brings about 3 g of leucine plus everything else. An EAA powder such as USN ALL9 Amino 330 g (R359.95–R362.99) costs about R11 per 10 g of powder, and its leucine per serving is not published in text. For picking one, see [best EAA supplement in South Africa](/answers/best-eaa-supplement-south-africa/) and [BCAA vs EAA](/answers/bcaa-vs-eaa-south-africa/).

## Any cautions?

Leucine is not a concern at food-level intakes. People with kidney or liver disease, maple syrup urine disease, pregnant women, under-18s and anyone on medication should check with a doctor or dietitian before taking amino powders. Compare proteins at [best whey protein in South Africa](/best/best-whey-protein-south-africa/) or [best plant protein](/best/best-plant-protein-south-africa/).

## Products mentioned

| Product | Size | Price (source, date) | Servings | R per 30 g protein | R per 100 g powder | Sweeteners |
|---|---|---|---|---|---|---|
| NPL Platinum Whey Plus (1 kg) | 1 kg | R490 (NPL shop (npl.za.com), 2026-10) | 25 | R23.52 | R49.00 | sucralose |
| Faithful to Nature (FtN) Pea Protein Isolate Powder (650 g) | 650 g | R148-R185 (Faithful to Nature, 2026-10) | — | R11.38 | R28.46 | none |
| USN BlueLab 100% Plant Based Protein (900 g) | 900 g | R399-R474.99 (Dis-Chem Living Fit, 2026-10) | — | R24.54 | R52.78 | sucralose, acesulfame-K, steviol glycosides |
| USN ALL9 Amino 330 g | 330 g | R359.95-R362.99 (USN online shop, 2026-10) | — | — | — | not stated |

## Sources

- [Jäger R et al. (2017) ISSN position stand: protein and exercise. JISSN](https://pubmed.ncbi.nlm.nih.gov/28642676/)
- [Wolfe RR (2017) Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? JISSN](https://pmc.ncbi.nlm.nih.gov/articles/PMC5568273/)
- [Australian Institute of Sport Supplement Framework: Group C (not advocated)](https://www.ausport.gov.au/ais/nutrition/supplements/group_c)