Leucine

Safe OtherSynthetic

Leucine is a synthetic other used in dietary supplements. Safety rating: Safe. It is widely considered safe at typical supplement doses. Found in 20 supplements in the GoodSupp database. Leucine is an essential branched-chain amino acid (BCAA).

20 Products use this
Safe Safety rating
Other Category
No Natural origin

Safety Verdict: Safe

This ingredient is rated safe for use in dietary supplements.

What is Leucine?

Leucine is an essential branched-chain amino acid (BCAA).

Common Names Leucine, L-Leucine
Type Other
Origin Synthetic / Manufactured
Safety Rating Safe

Why is Leucine used in supplements?

It is used for its potential muscle-building and recovery benefits.

Role in supplements: Other — serves a functional role in supplement formulation.

Should you be concerned about Leucine?

No. Leucine is widely regarded as safe for use in dietary supplements at typical levels. It has a long history of use and is accepted by major regulatory bodies.

No action needed. This ingredient is safe at amounts used in supplements.

Top-rated products containing Leucine

These 20 highest-scoring supplements in our database use Leucine.

Thorne Zinc Picolinate, 15 mg, 60 Capsules
Thorne Zinc Picolinate, 15 mg, 60 Capsules
Product 100 Brand N/A
Thorne Iron Bisglycinate, 60 Capsules (25 mg per Capsule)
Thorne Iron Bisglycinate, 60 Capsules (25 mg per Capsule)
Product 100 Brand N/A
Thorne Curcumin Phytosome, 60 Capsules (500 mg per Capsule)
Thorne Curcumin Phytosome, 60 Capsules (500 mg per Capsule)
Product 100 Brand N/A
Thorne Curcumin Phytosome, 120 Capsules (500 mg per Capsule)
Thorne Curcumin Phytosome, 120 Capsules (500 mg per Capsule)
Product 100 Brand N/A
Thorne Zinc Picolinate, 30 mg, 180 Capsules
Thorne Zinc Picolinate, 30 mg, 180 Capsules
Product 100 Brand N/A
Thorne Zinc Picolinate, 30 mg, 60 Capsules
Thorne Zinc Picolinate, 30 mg, 60 Capsules
Product 100 Brand N/A
Thorne Vitamin B12 as Methylcobalamin, 60 Capsules (1 mg per Capsule)
Thorne Vitamin B12 as Methylcobalamin, 60 Capsules (1 mg per Capsule)
Product 100 Brand N/A
Thorne Zinc Picolinate, 30 mg, 60 Capsules
Thorne Zinc Picolinate, 30 mg, 60 Capsules
Product 100 Brand N/A
Thorne Theanine, 90 Capsules (200 mg per Capsule)
Thorne Theanine, 90 Capsules (200 mg per Capsule)
Product 100 Brand N/A
Vital Nutrients St. John's Wort, 90 Vegan Capsules (300 mg per Capsule)
Vital Nutrients St. John's Wort, 90 Vegan Capsules (300 mg per Capsule)
Product 100 Brand N/A
Thorne Phosphatidylserine, 60 Capsules (100 mg per Capsule)
Thorne Phosphatidylserine, 60 Capsules (100 mg per Capsule)
Product 100 Brand N/A
Vital Nutrients Rhodiola Rosea, 120 Vegan Capsules (200 mg per Capsule)
Vital Nutrients Rhodiola Rosea, 120 Vegan Capsules (200 mg per Capsule)
Product 100 Brand N/A
Thorne Copper Bisglycinate, 60 Capsules (2 mg per Capsule)
Thorne Copper Bisglycinate, 60 Capsules (2 mg per Capsule)
Product 100 Brand N/A
Thorne Chromium Picolinate, 60 Capsules (500 mcg per Capsule)
Thorne Chromium Picolinate, 60 Capsules (500 mcg per Capsule)
Product 100 Brand N/A
Thorne D-1,000, 90 Capsules (25 mcg per Capsule)
Thorne D-1,000, 90 Capsules (25 mcg per Capsule)
Product 100 Brand N/A
Thorne Acetyl-L-Carnitine, 500 mg, 60 Capsules
Thorne Acetyl-L-Carnitine, 500 mg, 60 Capsules
Product 100 Brand N/A
Thorne Choleast-900, 120 Capsules (900 mg per Capsule)
Thorne Choleast-900, 120 Capsules (900 mg per Capsule)
Product 100 Brand N/A
Thorne Curcumin Phytosome, 120 Capsules (500 mg per Capsule)
Thorne Curcumin Phytosome, 120 Capsules (500 mg per Capsule)
Product 100 Brand N/A
Codeage Glutathione-SR+, 250 mg, 60 Vegetable Capsules
Codeage Glutathione-SR+, 250 mg, 60 Vegetable Capsules
Product 100 Brand N/A
Quality of Life CoQ10-SR®, 100 mg, 60 Vegicaps
Quality of Life CoQ10-SR®, 100 mg, 60 Vegicaps
Product 100 Brand N/A
Related Ingredients
3-0-Ethyl Ascorbic Acid Generally Safe 3-O-Ethyl Ascorbic Acid Generally Safe Acetyl Glucosamine Generally Safe Acetyl Hexapeptide-8 Generally Safe Adenosine Generally Safe Adhesive Caution Alanine Safe Alfalfa Leaf Generally Safe
Frequently Asked Questions
Is Leucine safe in supplements?

Yes. Leucine is rated safe for use in dietary supplements at typical levels. This rating is based on regulatory assessments, published safety research, and its long history of use in the supplement industry. It is widely accepted by major regulatory bodies including the FDA and EFSA. In GoodSupp's database, 20 products contain this ingredient. Consult your healthcare provider if you have specific concerns.

What is Leucine and why is it in my supplement?

Leucine is an essential branched-chain amino acid (BCAA). It appears in 20 products in the GoodSupp database.

Is Leucine natural or synthetic?

Leucine is synthetically produced, meaning it is manufactured through chemical processes rather than directly extracted from natural sources. Synthetic ingredients are extremely common in supplements and are not inherently less safe than natural alternatives. In many cases, synthetic production allows for higher purity and more consistent quality. The FDA regulates both natural and synthetic supplement ingredients under the same safety standards. GoodSupp rates ingredients based on their actual safety data regardless of whether they're natural or synthetic.

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Disclaimer: GoodSupp provides independent supplement quality analysis for informational purposes only. Scores are generated algorithmically based on ingredient profiles, brand certifications, and public records. This is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Product data is sourced from manufacturer labels and public databases. GoodSupp is not affiliated with any supplement brand.