Scores 35/35 for dosage transparency, 25/25 for a clean formula, 22/25 for label completeness. 6 ingredients disclosed with amounts.
capsule · 30 servings · $0.60/servingBuy on iHerb$17.86
Ranking
10 Best Amino Acid Supplements
Single amino acids are among the most transparent supplements you can buy: one ingredient, one amount. That makes this ranking mostly about the rest of the label: fillers, flavor systems, and whether a "complex" or blend still discloses what is in it.
We ranked L-theanine, L-carnitine, NAC, glutamine, arginine, tyrosine, BCAA and other amino-acid products sold on iHerb by label quality.
Our top picks
Scores 35/35 for dosage transparency, 25/25 for a clean formula, 22/25 for label completeness. 6 ingredients disclosed with amounts.
capsule · 30 servings · $1.07/servingBuy on iHerb$32.00
Scores 35/35 for dosage transparency, 25/25 for a clean formula, 22/25 for label completeness. 6 ingredients disclosed with amounts.
capsule · 60 servings · $0.53/servingBuy on iHerb$32.00
Top 10 ranked
#ProductScoreFormServingsPrice
How we ranked them
Every product is scored 0–100 from its label data in the NIH Dietary Supplement Label Database: dosage transparency (35 points - are amounts stated per ingredient, or hidden in a proprietary blend?), label completeness (25), formulation cleanliness (25 - fillers, dyes, titanium dioxide and other non-active ingredients) and ingredient profile (15). The Top 10 admits only products scoring 60 or higher; among those, products with a verified retail listing are shown first so the list is one you can act on. No brand can pay to be included or moved up.
Forms and dosage
- Free-form single amino acids
- L-theanine, L-tyrosine, L-glutamine and others as one ingredient. The simplest labels in the database.
- Derivatives (NAC, acetyl-L-carnitine)
- Modified forms; the label should say which form, since amounts differ.
- BCAA and EAA powders
- Ratios such as 2:1:1 should be stated with gram amounts per serving.
How much to take
Amounts used in studies vary by amino acid: L-theanine 100–200 mg, NAC 600–1,200 mg, L-carnitine 500–2,000 mg, glutamine 5 g and up, BCAA 5–10 g. There are no official upper limits for most amino acids, so a stated amount per serving is what lets you judge a product.
Who it's for
Adults who want a single, specific amino acid at a known dose.
What to watch out for
Amino "complexes" that give only a total weight, flavored powders with artificial colors, and serving sizes that reach the studied amount only at several capsules.
All Amino Acids products (5071)
1
NOW5-HTP 200 mg
902Protocol For Life Balance5 - HTP 200 mg
903Protocol For Life Balance5-HTP (5-Hydroxytryptophan) 200 mg
904BodyTechBCAA & Glutamine
895Doctor's BestNAC Detox Regulators
886Doctor's BestBest NAC Detox Regulators
887NutricostGABA 500 mg
868NOW SportsL-Carnitine Liquid 1000 mg Citrus Flavor
859Country LifeL-Theanine 100 mg Smooth Melts
8510NOW SportsLiquid L-Carnitine 1000 mg Citrus Flavor
8511NOWNAC 1,000 mg Quercetin 500 mg & Zinc 15 mg
8512Country LifeL-Theanine 100 mg Mint Flavored
8513NOWGABA 500 mg
8314NOW SportsL-Carnitine Liquid 1000 mg Tropical Punch Flavor
8315NOWDouble Strength 5-HTP 200 mg
8316NOWL-Methionine 500 mg
8317Swanson UltraDouble Potency Suntheanine L-Theanine 200 mg
8318Pure EncapsulationsCognitive Aminos
8319BodyTechCarnipure 3000 Candy Punch
8320BodyTechCarnipure 3000 Peach Mango
83Frequently Asked Questions
Are amino acid supplements safe?
Many are, at common doses, but people who are pregnant, have kidney or liver disease, or take medication should ask a clinician. Our score covers label quality, not safety for an individual.
Why do some BCAA products score poorly?
Usually because of artificial colors and sweeteners in flavored powders, or a blend that hides the ratio. Unflavored products with stated gram amounts score best.
How are amino acids supplements ranked?
Products are ranked by SupplementScore, which evaluates label quality across four categories: dosage transparency (35 pts), label completeness (25 pts), formulation cleanliness (25 pts), and ingredient profile (15 pts). The score is based on data from the NIH Dietary Supplement Label Database, not marketing claims.
Does a higher score mean the supplement is more effective?
No. The SupplementScore measures label quality, how transparent, clean, and well-documented a product is. It does not measure clinical efficacy, bioavailability, or third-party testing. A higher score means better label practices, not guaranteed results.
How many amino acids supplements were analyzed?
We analyzed 5,071 amino acids products from the NIH DSLD database, which contains label data for over 116,000 dietary supplements sold in the United States.
This article is for information only and is not medical advice. Talk to a clinician before starting a supplement, especially if you are pregnant, take medication or have a health condition.