If you’re looking to support your body’s glutathione production and antioxidant defenses, this provides the key building block. At one tablet, you're getting 500 mg of **L-Cysteine** — just below the 600 mg minimum used in clinical research. Following the label's suggestion of 1–3 tablets daily puts you at 500–1,500 mg, comfortably within the studied range for supporting liver health and antioxidant capacity.

You're also getting 60 mg of **Vitamin C** and 10 mg of **Vitamin B6**, both of which play supporting roles in cysteine metabolism and glutathione recycling. These are modest doses — well below their own clinical ranges — so think of them as functional co-factors rather than standalone contributors.

One thing worth knowing: if you're supplementing for glutathione support, most clinical research actually uses NAC (N-Acetyl-L-Cysteine), which is more stable and better studied. Free-form L-Cysteine is less researched as a standalone supplement, so the evidence base here is thinner than the dose alone might suggest.

BioStacks
NOW

L-Cysteine 500 mg

Tablet · 100 servings · $0.13/serving

38 / 100Poor

Score Breakdown

Formulation
38
Safety
100
Final score
38/100

Ingredients (3)

L-Cysteine Hydrochloride500 mg

Partial dose

Vitamin B610 mg

Partial dose · Budget form

Vitamin C60 mg

24% of effective dose · Budget form

Label Nutrition Facts

Other Ingredients

Fillers, coatings, and additives

4Safe

Magnesium StearateLubricant

Safe

Silicon DioxideAnti-caking

Safe

Citric AcidAcidulant

Safe

Microcrystalline CelluloseBinder

Safe

Vegetarian Coating (coating)

Unknown

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Sources & Scoring

Nutrient data (RDA, UL, and safety thresholds) sourced from: NIH Office of Dietary Supplements and National Academies Dietary Reference Intakes (DRI).

This is not medical advice. Consult a healthcare provider before making changes to your supplement routine.

The score analyzes what's on the label: ingredient doses vs. clinical ranges, chemical forms, evidence levels, and known interactions. It does not verify label accuracy or test for contaminants — for that, look for third-party certifications like USP or NSF.