| 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 | 800 mg | 889% |
| Vitamin D3 | 25 mcg | 125% |
| OptiZinc | 15 mg | 136% |
Other ingredients: Hydroxypropyl Methylcellulose, Ascorbyl Palmitate
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.
Supports immune cell function. Regular supplementation may modestly reduce cold duration, but does not prevent colds.
Potent water-soluble antioxidant that protects cells from oxidative damage.
Essential cofactor for enzymes involved in collagen production.
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.
Essential for calcium absorption. Deficiency leads to rickets in children and osteomalacia in adults — a well-established causal relationship.
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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 Douglas Laboratories. 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 (Zinc) with a higher overall score. This is not a recommendation — always verify ingredients and dosages match your needs.
May reduce risk of respiratory infections. Active area of research.
Some association between low vitamin D levels and depression, but evidence is inconsistent.