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Reference product
NOW Foods L-Cysteine 500 mg
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Evaluation graph
Based on the average score
Based on the selling price
How we evaluate
Primary ingredients How we evaluate

We focus on L-cysteine content (mg) per daily intake as a key indicator, evaluating whether ~2000mg-appropriate recommended intake is met. Products significantly deficient or excessive receive point deductions. We examine whether it's absorbable L-cysteine (free form) or Cystine/complex form. We verify raw material quality and production methods (pure fermentation process), plus test report provision.
Price How we evaluate

We convert to recommended daily intake-basis pricing to compare mg-per-unit cost-effectiveness. We comprehensively evaluate content, formulation, and absorption efficiency beyond just price. We examine whether cost-effectiveness is sustained during long-term consumption compared to same-price-range products.
Brand How we evaluate

We verify GMP, HACCP, health functional food certification. We review test report (CoA) provision, other international certification status, raw material origin/manufacturer disclosure. We highly evaluate brands with clear raw material sources and established quality management systems, plus clinical/research evidence provision.
Quality How we evaluate

We evaluate product purity (100% notation = highest score, no notation = point deduction), formulation characteristics (L-cysteine single-ingredient status), special coating/processing, and tablet size (consumption convenience). We verify oxidation/moisture/light-breakdown-prevention packaging, individual packaging presence, disintegration time and absorption speed, and long-term storage stability. We examine unnecessary additive excess and allergen-component exclusion.
Additional ingredients How we evaluate

We evaluate whether hair loss/skin/antioxidant improvement-supporting components (biotin, zinc, vitamin B5, B6, etc.) are included and daily fulfillment status. Point deduction applies for biotin absence, while ≥5-component inclusion earns highest score. We verify clear labeling of component origin/content, unnecessary synthetic additive minimization. We positively evaluate additional antioxidant (glutathione, vitamin C, etc.) ingredient inclusion showing synergy.
Detailed score comparison
| Evaluation criteria | |
|---|---|
| Primary ingredients | 100 |
| Additional ingredients | 72 |
| Quality | 83.6 |
| Brand | 89.5 |
| Value | 87.1 |
| Lowest price |
Prices shown are current sale prices and do not account for serving size. Actual prices may vary by quantity and package configuration.