How Qoyl Scores Products
No black box. No brand bias. Here's exactly how your compatibility score is calculated.
What the score means
Your score is personal. Someone else's 4c high porosity hair in Houston will get a different score on the same product than your 2b low porosity hair in Chicago. That's the point.
Strong match
This product's ingredient profile aligns well with your hair's needs. The key ingredients score positively for your porosity level and hair type, and we didn't flag anything that commonly causes problems for your specific profile. This doesn't mean it will work perfectly - individual responses vary - but the ingredient science supports it.
Proceed with caution
This product has a mixed ingredient profile for your hair. Some ingredients score well, others are flagged as potential concerns for your porosity or hair type. Read the ingredient breakdown before purchasing - the caution flags will tell you exactly what to watch for.
Not recommended for your profile
Several ingredients in this product are flagged as problematic for your specific hair profile. That doesn't mean the product is bad - it may work beautifully for someone with different porosity or curl type. But the ingredient science suggests it's worth exploring other options first.
What goes into your score
Seven variables. One score.
01
Curl type (1a–4c)
Your curl pattern affects how products distribute through your hair, how much tension and manipulation your hair can handle, and which hold agents and stylers work best. Tight coils need different slip and moisture-sealing than loose waves.
02
Porosity
Porosity is the single most important variable in our scoring. It determines whether an ingredient actually enters your hair shaft or sits on top of it. Low porosity hair resists absorption - heavy humectants and butters can build up. High porosity hair absorbs quickly but loses moisture just as fast - it needs sealants and protein to hold moisture in.
03
Scalp condition
Your scalp condition affects which cleansing agents, preservatives, and active ingredients we flag. Sensitive scalps get stronger warnings on fragrance, essential oils, and harsh surfactants. Dandruff-prone scalps get different guidance on antifungal ingredients.
04
Climate (from your zip code)
Climate changes everything about how humectants behave. Glycerin in humid Miami pulls moisture into your hair. Glycerin in dry Phoenix pulls moisture OUT of your hair. We factor in your local humidity and temperature data to adjust humectant scoring accordingly.
05
Strand thickness
Fine strands can be weighed down by ingredients that work beautifully on coarse strands. We adjust scoring for heavy butters, oils, and film-forming polymers based on your strand thickness.
06
Water hardness (from your zip code)
Hard water deposits calcium and magnesium on the hair shaft, blocking moisture and making products less effective. We factor your local water hardness into how we score chelating agents and clarifying ingredients - if you're in a hard water city, we weight those ingredients more favorably.
07
Age range
Hair texture, density, scalp oil production, and protein tolerance all change with age. We apply age-aware scoring adjustments - particularly for users over 35 who may be experiencing hormonal-related texture changes, thinning, or increased scalp sensitivity. Older age ranges receive higher scores for scalp-stimulating and strengthening ingredients and lower scores for heavy proteins and harsh surfactants.
How ingredient scores are calculated
Every ingredient has a score. Your profile determines which ones matter most.
Qoyl maintains a database of hair care ingredients, each scored on a 0–10 scale for low, medium, and high porosity hair separately. A score of 8–10 means the ingredient is well-suited for that porosity level. A score of 4–7 is neutral - present but not a significant help or harm. A score of 0–3 means the ingredient is commonly problematic for that porosity level.
Your product's compatibility score is calculated by matching every ingredient in the product against our database, applying your porosity score to each match, and weighting by ingredient position - an ingredient listed first is present in higher concentration than one listed last, so it carries more weight in the final score.
The final 0–100 score is a weighted average across all matched ingredients, scaled to reflect both the concentration of each ingredient and its compatibility with your specific porosity level.
What our scores don't tell you
Honest limitations.
Qoyl scores cosmetic compatibility - not medical outcomes. Our scores reflect ingredient-level data and hair science, not clinical trials or guaranteed results. Individual responses to ingredients vary based on factors we don't capture: medication, hormonal changes, water temperature, application technique, and more.
A high score means the ingredient profile aligns with your hair's needs. It doesn't guarantee the product will work for you. A low score means the ingredient profile raises concerns for your profile - it doesn't mean the product is dangerous or won't work for anyone.
We do not address medical hair loss, scalp conditions requiring medical treatment, or any health-related concerns. If you are experiencing significant hair loss, scalp pain, or other symptoms, please consult a licensed dermatologist.
Our commitment to independence
No brand pays to improve their score.
Every score on Qoyl is generated by our algorithm from the product's ingredient list and your hair profile. Brand partners who access our B2B dashboard see their scores - they don't influence them. Affiliate relationships with retailers do not affect compatibility scores. A product that scores 34 will always score 34 for your profile, regardless of whether we have an affiliate relationship with the brand.
If we ever change our scoring methodology, we will document the change and explain why.
Last updated August 10, 2026
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