| Ingredient | Amount | % DV% Daily Value — how much of the recommended daily intake one serving provides, based on a 2,000 calorie diet. 100% = full daily need. Values over 100% are common for water-soluble vitamins (B, C) and generally safe. Values over 200% are highlighted. |
|---|---|---|
| Vitamin C | 100 mg | 167% |
| Magnesium | 200 mg | 50% |
| Zinc | 15 mg | 100% |
| Copper | 500 mcg | 25% |
| Manganese | 5 mg | 250% |
| Molybdenum | 220 mcg | 293% |
| Glucosamine Sulfate | 1500 mg | — |
| MSM | 1500 mg | — |
| Hyaluronic Acid | 80 mg | — |
| FLEXICOL(TM) Proprietary Blend | 965 mg | — |
Other ingredients: Hydroxypropyl Cellulose, Stearic Acid, Croscarmellose Sodium, Cellulose, Silicon Dioxide, Titanium Dioxide, Magnesium Stearate
This score evaluates label quality — dosage disclosure, transparency, cleanliness of inactive ingredients, and formula composition. It does not measure clinical efficacy, bioavailability, or third-party testing. Read full methodology
Same category, higher SupplementScore. Based on dosage transparency, label cleanliness, and formula quality.
The research summaries below are about the ingredients in general, drawn from published studies that often use different doses, forms, and populations than this product. A "strong" evidence rating for an ingredient does not mean this product will produce that effect — studied doses may be significantly higher or lower than what is contained here. Always verify doses against the Supplement Facts table above.
Zinc is a cofactor for over 300 enzymes involved in immune cell development and function. Supplementation may reduce duration of common cold symptoms, particularly as lozenges. Essential for maintaining immune barrier integrity.
Essential for skin integrity and wound repair processes.
May improve sleep quality, especially in older adults and those with low magnesium status.
60% of body magnesium is stored in bone. Essential for bone mineralization.
May reduce muscle cramps and support post-exercise recovery.
Supports immune cell function. Regular supplementation may modestly reduce cold duration, but does not prevent colds.
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All scores are algorithmically generated from publicly available label data (NIH Dietary Supplement Label Database) and reflect label quality — not clinical efficacy, safety, or product quality. This page is not affiliated with or endorsed by 21st Century. If you represent this brand and believe any information is inaccurate, please contact us for a correction. Read full methodology
Alternatives are selected from the same category (Vitamin C) with a higher overall score. This is not a recommendation — always verify ingredients and dosages match your needs.
Potent water-soluble antioxidant that protects cells from oxidative damage.
Essential cofactor for enzymes involved in collagen production.