How the N+ Score Works
Every product receives a score from 0 to 100 based on four objective dimensions. No opinions, no sponsorships, no affiliate bias — just data from the supplement label compared against clinical research.
Scoring Overview
The N+ Score is a composite metric calculated from four weighted pillars. Each pillar evaluates a different aspect of supplement quality using data extracted from the NIH Dietary Supplement Label Database (DSLD), which contains label information for over 200,000 products sold in the United States.
Our scoring algorithm compares each product's ingredient profile against a curated reference database of 90 key ingredients with clinically validated dose ranges. The result is a single number that represents how well a product delivers on its category's promise.
The Four Scoring Pillars
Ingredient Adequacy
35%Measures whether key active ingredients meet evidence-based clinical dose thresholds. We compare each ingredient's listed amount against published research from NIH ODS Fact Sheets and peer-reviewed meta-analyses.
- Each ingredient is compared against a minimum effective dose from clinical literature
- Ingredients at or above the clinical threshold score 100% for that ingredient
- Ingredients between 50-99% of the threshold receive proportional credit
- Below 50% of the threshold receives minimal credit
Formula Completeness
25%Evaluates whether the product contains all expected ingredients for its supplement category. A fish oil should have EPA and DHA. A multivitamin should cover essential vitamins and minerals.
- Category-specific ingredient checklists define what a complete formula looks like
- Products are scored on what percentage of expected ingredients are present
- Bonus points for including synergistic cofactors (e.g., Vitamin K2 with D3)
- Penalties for missing core ingredients that define the category
Label Transparency
20%Assesses whether the product fully discloses individual ingredient amounts on its label. Proprietary blends that hide individual doses score lower. Full disclosure earns the highest marks.
- Products with 100% of ingredients individually quantified score highest
- Proprietary blends with hidden amounts receive significant penalties
- Partial disclosure receives partial credit
- "Other ingredients" transparency is also factored in
Ingredient Diversity
20%Measures the breadth of the formula relative to category norms. A comprehensive multivitamin with 25 ingredients scores higher than one with 10, provided the additional ingredients are relevant.
- Compared against the median ingredient count for the product's category
- More relevant ingredients earn higher scores, up to a category-specific ceiling
- Irrelevant filler ingredients do not contribute positively
- Normalized to prevent unfair advantage for categories with naturally more ingredients
Letter Grade Scale
The numeric score (0-100) maps to a letter grade for quick reference.
| Grade | Range | Interpretation |
|---|---|---|
| A | 93-100 | Exceptional — clinical doses met, full transparency, comprehensive formula |
| A- | 87-92 | Excellent — near-optimal dosing with minor gaps |
| B+ | 83-86 | Very Good — strong formula with room for improvement |
| B | 77-82 | Good — solid product with some dosing or transparency gaps |
| B- | 73-76 | Above Average — decent formula, several areas to improve |
| C+ | 67-72 | Average — meets basic standards but lacks optimization |
| C | 60-66 | Below Average — significant gaps in dosing or transparency |
| D | 40-59 | Poor — major deficiencies in multiple scoring dimensions |
| F | 0-39 | Failing — insufficient ingredient data or severely underdosed |
Data Sources
Our scoring relies on publicly available, peer-reviewed data sources. We do not accept payments from supplement brands.
NIH DSLD
Dietary Supplement Label Database — the primary source for all product label data.
NIH ODS
Office of Dietary Supplements fact sheets provide recommended daily allowances.
Clinical Literature
Peer-reviewed meta-analyses inform our clinical dose reference thresholds.
Frequently Asked Questions
How often are scores updated?
Scores are recalculated whenever new label data is added to the NIH DSLD. We run batch updates periodically to ensure our database reflects the latest available information.
Can brands pay to improve their score?
No. The N+ Score is entirely algorithmic and based on publicly available label data. We do not accept payments from brands, and there is no way to influence a score outside of reformulating the actual product.
Why does my favorite supplement have a low score?
A low score typically means the product has underdosed key ingredients, uses proprietary blends that hide individual amounts, or is missing expected ingredients for its category.
What about third-party testing?
Our current scoring focuses on what's on the label. Third-party testing (NSF, USP) verifies that what's on the label is actually in the product. We plan to incorporate certification data in future updates.
How do you handle proprietary blends?
Products with proprietary blends receive lower Label Transparency scores because individual ingredient amounts are hidden. If a blend lists total weight but not individual doses, we cannot verify clinical dosing.