Potency
Beta-glucan content measured against label claim using HPLC quantification or the Megazyme assay.
Methodology · calibrated 2026
NootroScore
A 7.0 to 9.8 rating that compresses four evidence-weighted factors into a single number you can compare across brands. Floor protects against false negatives, hardcap protects against marketing.
7.0 Floor 8.4 Strong 9.8 Hardcap
What NootroScore measures
Every NootroScore starts at a base of 6.8, the floor we assign to any product that has cleared a third-party retail review. It is then adjusted by four weighted factors, each scored 0 to 10 in our editorial review, with weights that vary by category. The raw sum is then run through a compression curve to keep the upper end honest.
The four factors
Purity
Heavy-metals screening (ICP-MS) and microbial testing against USP-grade thresholds.
Value
Cost per active milligram of beta-glucan, normalized across formats.
Transparency
Sourcing disclosure, public certificate-of-analysis access, and label accuracy.
Weights shown are the defaults for Lion's Mane comparisons. Other categories override these defaults via the nootroscoreWeights field on the comparison record.
The formula
raw = 6.8 + sum(score / 10 × weight × 3.0)
With default Lion's Mane weights, a product scoring 10 across all four factors lands exactly on the 9.8 hardcap before compression. In practice, that combination almost never occurs, which is the point of the cap.
Compression curve
- 9.0+ Excess multiplied by 0.7. A 9.4 becomes 9.28.
- 9.5+ Excess multiplied by 0.5. A 9.7 becomes 9.6.
- 9.8 Hardcap. No product can exceed it.
- 5.0 Floor. Products below this still bottom out here.
Worked example
Hypothetical Lion's Mane v3 capsule
| Factor | Score | Weight | Contribution |
|---|---|---|---|
| Potency | 9 / 10 | 40% | +1.08 |
| Purity | 9 / 10 | 25% | +0.68 |
| Value | 8 / 10 | 20% | +0.48 |
| Transparency | 9 / 10 | 15% | +0.41 |
| Base | 6.80 | ||
| Raw total | 9.44 | ||
| NootroScore (after compression) | 9.31 | ||
raw 9.44 exceeds 9.0; excess multiplied by 0.7 -> 9.31.
Score scale
- 9.5+ Exceptional
Outstanding products with publicly verifiable COAs, strong value, and full label transparency. Approaching the 9.8 ceiling.
- 9.0+ Strong
Top-tier supplements that perform well across all four factors and represent the best options in their category.
- 8.5+ Excellent
Reliable picks with competitive pricing and good lab signals. Highly recommended for most readers.
- 8.0+ Very good
Solid products that meet most criteria but trail the leaders on at least one factor.
- 7.0 Baseline
The minimum NootroScore. Products at this level meet basic verification but lack standout value, transparency, or potency.
What NootroScore does not measure
- Subjective experience. NootroScore does not predict how a supplement will feel. Two products with the same score can land differently with two readers because individual response varies.
- Long-term safety beyond label-grade testing. Heavy metals and microbials are screened. Idiosyncratic reactions, drug interactions, and pregnancy-related risk are out of scope.
- Stack chemistry. NootroScore rates a single product. The interaction profile when combined with other supplements or medications is not in the formula.
- Brand reputation outside the four factors. Customer service, return policy, and shipping speed do not affect the score.
FAQ
Is NootroScore influenced by sponsors or affiliate partners?
No. The score is calculated from cited primary research, publicly available COAs, retail pricing, and label transparency. Affiliate links pay the bills, but they do not move scores up or down. When two products are within 0.3 NootroScore of each other, we surface both rather than picking the one with a higher commission.
How often are scores updated?
Whenever the underlying data changes: a price shift, a new COA from a manufacturer, a label revision, or a fresh in-house lab pull. Major comparisons re-score every 90 days at minimum.
Can a product's score change over time?
Yes. NootroScore factors in pricing and transparency, both of which can shift. A product can lose ground if its third-party COA goes stale, or gain ground if it cuts price per active milligram or adds USP verification.
Why is the maximum score 9.8 and not 10?
A perfect 10 implies a flawless product with no remaining room for improvement, which is not a credible claim for any supplement. Capping at 9.8 keeps the scale honest and reserves headroom for a category-defining release.
Can the same product have different scores in different categories?
Yes. The four-factor weights are tunable per category. The defaults shown here are calibrated for Lion's Mane comparisons. A category like Omega-3, where third-party oxidation testing matters, may shift weight toward Purity. The override lives on the comparison record itself.