Understanding Your HumanSafe™ Score

A practical guide to reading and interpreting HumanSafe™ scores, badges, and classifications. Learn what each letter grade means and how to make informed decisions.

New to HumanSafe™? For an overview of our approach and philosophy, visit our About page. This guide focuses specifically on how to read and use our scores.
The Basics

The HumanSafe™ Scoring System

HumanSafe™ evaluates products across four independent dimensions. Each serves a different purpose and helps you make informed decisions based on what matters most to you.

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HSS - Human Safety

Letter Grade (A+ to F)

Health risk assessment considering concentration, exposure, duration, and target population. This is the most important score for safety.

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ESS - Environmental

Numerical (1.0–10.0)

Environmental impact including biodegradability, aquatic toxicity, and manufacturing footprint. Higher is better for the planet.

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CTS - Transparency

Numerical (1.0–10.0)

How openly the company shares ingredient data, concentrations, and sourcing information. Higher means more transparent.

CES - Experience

Numerical (1.0–10.0)

Real-world performance and user satisfaction based on verified customer feedback. Higher means better experience.

Why four separate scores? Safety, environmental impact, transparency, and experience are different concerns. Combining them into one number would hide important trade-offs and nuances.
Reading Letter Grades

What Each HSS Score Means

Human Safety Score (HSS) uses letter grades for quick recognition. Here's what each grade means in plain language, with both consumer-friendly and technical classifications.

Human Safety Score
A+
Exceptionally Safe

9.0–10.0 Range
Elite Biocompatibility

Human Safety Score
A
Very Safe

8.0–8.9 Range
High Safety Integrity

Human Safety Score
A-
Generally Safe

7.0–7.9 Range
Functional Safety

Human Safety Score
B
Use With Caution

6.0–6.9 Range
Exposure-Conditional

Human Safety Score
C
Significant Concerns

5.0–5.9 Range
Toxicological Alert

Human Safety Score
D
High Concern

4.0–4.9 Range
High Toxicological Risk

Human Safety Score
F
Avoid If Possible

< 4.0 Range
Biocompatibility Breach

Complete Reference

HSS Score Chart: Full Breakdown

Use this chart to understand what each score means, both in everyday language and technical terms.

Grade Range What It Means What To Do
A+ 9.0–10.0 Exceptionally Safe
Best-in-class formulations with minimal concerns
Trust and confidence. These are elite safety profiles.
A 8.0–8.9 Very Safe
Reliable and trustworthy products
Very safe for most users. Only minor considerations.
A- 7.0–7.9 Generally Safe
Acceptable safety, context-dependent concerns
Check ingredient details for your specific situation.
B 6.0–6.9 Use With Caution
Moderate concerns present, review carefully
Consider your personal sensitivities and usage patterns.
C 5.0–5.9 Significant Concerns
Notable considerations for some users
Review allergens carefully and consider patch testing.
D 4.0–4.9 High Concern
High risk profile with serious concerns
Avoid or consult healthcare provider before use.
F < 4.0 Avoid If Possible
Very high risk, may be restricted
Do not use without medical supervision.
Important to Know

Context Changes Everything

The same ingredient can have different scores depending on how it's used. We factor in concentration, product type, and target users.

Example: A Preservative in Different Products

In rinse-off shampoo (0.2%): Score A — Brief contact, low concentration, washes away quickly.

In leave-on face cream (0.5%): Score A- — Longer exposure on sensitive facial skin, higher concentration.

For baby products (0.2%): Score B — Higher safety standards for infants even at low concentration.

Remember: Scores reflect real-world use, not just theoretical maximum toxicity. We evaluate how products are actually used, not worst-case lab scenarios that never happen in practice.
Allergen Fairness

Understanding Allergen Notices

Some products may show allergen warnings even with high safety scores. This is part of our "allergen fairness" approach—protecting the 2% who are sensitive without penalizing the 98% who aren't.

Example: Linalool (Natural Lavender Component)

General Population Score: A (Very Safe)
Safe for 98%+ of people. Natural, well-studied ingredient with excellent safety profile.

Allergen Notice: ⚠️ ~1-2% may be sensitive
Small percentage of people have fragrance allergies. Check if you have known sensitivities to lavender or essential oils.

If You Have Linalool Allergy: Score C (Avoid)
Personalized score reflects documented allergy. System adjusts for your needs.

Personalized Scores: Create a free account to set your allergens. You'll see personalized scores that account for your specific sensitivities, so you never have to worry about hidden allergens.
Our Science

How We Calculate Your Score

Every score is based on scientific factors, weighted by importance, and adjusted for real-world context.

The 7 Core Factors (Weighted):

  • Acute Toxicity: Immediate harm potential based on LD50 data
  • Chronic Toxicity : Long-term repeated exposure effects
  • Skin Safety : Irritation and sensitization potential
  • Organ/System Toxicity: Effects on organs and body systems
  • Carcinogenicity : Cancer risk based on IARC/NTP classifications
  • Regulatory Approval : FDA, EU, and international clearances
  • Quality of Evidence : Strength and reliability of data

Then We Adjust For:

  • Product Type: Rinse-off vs. leave-on vs. spray
  • Concentration: How much of the ingredient is actually present
  • Exposure Route: Skin contact vs. ingestion vs. inhalation
  • Target Population: Adults, children, babies, pregnancy
Want the technical details? See our complete Methodology page for detailed scoring formulas, data sources, and version history.
Limitations

What Scores Don't Tell You

HumanSafe™ scores are powerful tools, but they have limitations. Here's what they do and don't cover.

✓ What Scores Tell You

  • Safety based on peer-reviewed toxicology research
  • Real-world risk considering how products are used
  • Context-appropriate assessment for your situation
  • Known allergen prevalence and warnings

✗ What Scores Don't Tell You

  • Product performance: We assess safety, not whether it works well
  • Personal suitability: Individual reactions vary—always patch test
  • Medical advice: Consult healthcare providers for health decisions
  • Regulatory compliance: We're independent, not a certification agency
Always remember: High scores mean population-level safety based on science. Your individual response may differ. Discontinue use if you experience any adverse reactions, regardless of score.

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