Amino acids

L-leucine

One of the nine essential amino acids, found in all protein foods. It’s the signal that tells muscles to start building new protein.

20 products from US online stores, sorted by what 3 g of leucine costs – not by the price per pack.

$0.11Lowest cost
per 3 g leucine

Prices checked Nov 1, 2026, US
No paid placements

What does 3 g mean?

leucine per serving in most of the products we checked: 1.6–5 gleucine per serving in most of the products we checked

3 g is a fixed amount to compare by: half of the 20 products we checked have up to 5 g per serving, the other half more.
There’s no official daily amount for leucine.

We compare by 3 g only so products line up – it’s not a recommendation. Not medical advice.

Where products miss quality points

How the 20 products score

Very good 90+: 1
Good 75+: 18
Fair 60+: 1
Low under 60: 0

have no seal from an independent testing program: 95%have no seal from an independent testing program10 of 30 testing points for GMP, 15 for the 6 whose label says “third-party tested”

The full 30 testing points need an independent test. Every supplement sold in the US is made under the FDA’s GMP rules – the maker checks its own products, which gives 10 points. A seal from a testing program like NSF, USP or Informed Choice means a lab outside the company checks that what’s inside matches the label. Most brands don’t take part. That doesn’t make a product bad – without a seal, a clean product still gets up to 80.

We find seals on the label and in NSF’s public lists. USP and Informed Choice don’t let us search their lists automatically, so a seal that’s only in their lists can be missing. How the score works

Good to know

Fact: 755%more per 3 g for the most expensive product than for the cheapest.
Fact: 270%more per 3 g for the cheapest capsules than for the cheapest powder.

How we checked: one-time price for each size in the store’s US online shop, before sales tax and shipping, without subscriptions or coupons. Prices change often, so check the store before you buy. More on how we check

The amount we compare by only makes products comparable – it is not a dosage recommendation. Not medical advice.

How we calculate

Cost per dose = price ÷ (servings × amount per serving) × comparison amount. Example: $119.99 for 74 servings with 24 g of protein each is 1,776 g of protein. $119.99 ÷ 1,776 g × 30 g = $2.03 per 30 g of protein.

Found a mistake or a product we should add? Email us

L-leucine

What does 3 g mean?

Where products miss quality points

Pack size

L-Leucine, Unflavored

L-Leucine Powder

L-Leucine Powder

L-Leucine, Unflavored

L-Leucine Powder

L-Leucine Pure Powder

L-Leucine, Unflavored

L-Leucine Powder

Essentials, Leucine+

Leucine

L-Leucine

L-Leucine Powder

Sports, L-Leucine Powder

L-Leucine Capsules

L-Leucine Powder

L-Leucine

L-Leucine Capsules

L-Leucine - Featuring AjiPure

L-Leucine

L-Leucine, 500 mg

Good to know