PlainVitamins

N-Acetyl-L-Cysteine 500 mg

by Klaire Labs · capsule · 90 vegetarian capsules

  • Off the market since February 2025 (NIH)
  • UPC 8 28054 00255 5
  • DSLD label 322413
  • Serving 1 capsule
  • 90 servings

N-Acetyl-L-Cysteine 500 mg by Klaire Labs lists one ingredient: 500 mg of N-acetyl cysteine per serving of 1 capsule. Its current label entered the NIH Dietary Supplement Label Database on December 21, 2024.

What is in N-Acetyl-L-Cysteine 500 mg?

Each row as the label prints it, per serving of 1 capsule. The capsule beside an amount places it among every product in the NIH database that lists the same ingredient: the bar is the middle half of their amounts, the line in it the median, the whiskers the 10th and 90th percentiles; the green tick is the FDA Daily Value and the red dashed tick the adult upper limit (IOM).

N-Acetyl-L-Cysteine 500 mg: Supplement Facts rows against the market (DSLD label 322413, January 2026 release)
IngredientAmount% DVAmong products listing it
N-Acetyl Cysteine500 mgN-Acetyl Cysteine in N-Acetyl-L-Cysteine 500 mg against 1,259 products500 mg per serving; the middle half of products list 55 mg to 500 mg, the median 150 mg.500 mg

Higher than 74% of 1,259 products listing N-acetyl cysteine (median 150 mg). Per day at the most servings: 1,000 mg.

Source: NIH ODS Dietary Supplement Label Database, label 322413 (entered December 21, 2024), version 9.4.0. See the label on DSLD or its label image (PDF). Amounts are what the maker printed; DSLD does not test products. Daily Values: the FDA's Daily Value page.

Is that a lot?

Every amount on this label with a position sits within the middle 80% of the products that list the same ingredient.

The NIH database records 1 to 2 servings a day from the label's directions; its % Daily Values are for adults and children 4 or more years of age. The directions as printed are further down this page.

The Tolerable Upper Intake Level is the most of a nutrient per day, from food, water and supplements together, that is likely to pose no risk for almost all adults (Institute of Medicine, 2011). It does not apply under medical supervision. This page compares labels; it is not medical advice.

Sources: amounts from the DSLD label; Daily Values from 21 CFR 101.9(c)(8)(iv); adult upper limits from the Institute of Medicine's DRI summary tables (2011). How positions are computed.

Which products have the closest formulas?

6 products list the very same ingredients; the nearest amounts come first.

Source: ingredient lists of every product's current label in DSLD (version 9.4.0); similarity weights each shared ingredient by how rare it is.

What does the label say about taking it?

Quoted from the label as DSLD transcribed it: the maker's words, including any claim about what the product does, which the FDA has not evaluated and PlainVitamins does not endorse.

Directions
Suggested use: 1 capsule, 1 to 2 times daily or as directed by a healthcare professional. It is recommended that this product be taken with a multiple vitamin and mineral supplement.
Warnings
Do not use if shrinkwrap is broken or missing.
Caution: If you are pregnant, nursing, have a medical condition, or taking prescription drugs, consult your physician before using this product.
Keep out of reach of children.
Allergens and what it does not contain
Free of the following common allergens: Milk/casein, eggs, fish, shellfish, tree nuts, peanuts, wheat, gluten, soybeans, corn and yeast. Contains no artificial colors, flavors, or preservatives.
Storage
Store in a cool, dry place (59 degrees F - 85 degrees F) away from direct light.

Source: label statements in DSLD label 322413.

What else is on the label?

Other ingredients: Hydroxypropyl Methylcellulose, Water, Microcrystalline Cellulose, Ascorbyl Palmitate, Silicon Dioxide.

How many labels does N-Acetyl-L-Cysteine 500 mg have?

One label is on file, entered on December 21, 2024.

  1. Label 322413 (current) Entered December 21, 2024 · off the market February 18, 2025 · 90 vegetarian capsules · UPC 8 28054 00255 5

Source: DSLD label entry and market events, version 9.4.0 (labels entered through September 25, 2025).

Who makes it?

The label names SFI USA (manufacturer), Reno, NV. All Klaire Labs products.

Where next?