PRESERVATIVE
Benzoic Acid
- preservative
A food-grade preservative that only works in acidic formulas, which is why it usually appears next to citric acid.
- products in our library
- 314
- of researched products
- 8%
- on the label, in our shampoos
- usually #22
- most common in
- Shampoo
- in water
- Water-soluble
At a glance
Four things worth knowing about how this ingredient behaves on hair.
How much of it is left on hair between washes.
What it takes to get it off the hair again.
What it is in the formula to protect.
Where it sits on the labels we have, in the category it appears in most.
| Property | Level | Out of |
|---|---|---|
| Buildup risk | Low | 1 of 5 |
| Rinse-out behaviour | Rinses clean | 5 of 5 |
| Role | Keeps water-based formulas | 4 of 5 |
| Prominence | Secondary | 2 of 5 |
What it does for a formula
What Benzoic Acid does
The general function first, then how the role changes by product type where we have researched it.
Anything with water in it needs one, over the life of the bottle.
Water alone removes it, so it does not accumulate between washes.
Charge
Negatively charged, like the hair surface itself — so it is repelled rather than attracted, rinses away cleanly, and is the charge most detergents carry.
Solubility
Rinses out with water alone — it does not accumulate on hair between washes.
Where it appears
Where it appears
One row per product category in our library: how many products list it, what share of that category that is, and where it typically sits on the label.
| Product type | How common | Typical position on label ? |
|---|---|---|
Shampoo
109 products
|
secondary · #22 | |
Conditioner
68 products
|
secondary · #17 | |
Leave-in
38 products
|
secondary · #20 | |
Mask / treatment
25 products
|
secondary · #28 | |
Styler: mousse
12 products
|
secondary · #14 | |
Styler: gel
9 products
|
secondary · #16 | |
Heat protectant
7 products
|
secondary · #24 | |
Styler: curl cream
5 products
|
secondary · #18 | |
Styler: hairspray
5 products
|
secondary · #12 | |
Co-wash
4 products
|
secondary · #18 |
12 more product types
| Product type | How common | Typical position on label ? |
|---|---|---|
Finisher: shine spray
4 products
|
secondary · #21 | |
Scalp treatment
4 products
|
secondary · #20 | |
Styler: smoothing cream
4 products
|
secondary · #32 | |
Styler: lotion
3 products
|
secondary · #10 | |
Styler: paste
3 products
|
secondary · #16 | |
Styler: texture spray
3 products
|
secondary · #15 | |
Styler: volumizer
3 products
|
secondary · #30 | |
Finisher: oil
2 products
|
secondary · #29 | |
Finisher: serum
2 products
|
secondary · #23 | |
Styler: edge control
2 products
|
secondary · #22 | |
Finisher: end oil
1 product
|
secondary · #18 | |
Styler: refresh spray
1 product
|
secondary · #11 |
| Product type | Products | Share of category | Median position | Earliest position | Band |
|---|---|---|---|---|---|
| Shampoo | 109 | 13% | 22 | 1 | secondary |
| Conditioner | 68 | 10% | 17 | 6 | secondary |
| Leave-in | 38 | 9% | 20 | 7 | secondary |
| Mask / treatment | 25 | 6% | 28 | 9 | secondary |
| Styler: mousse | 12 | 9% | 14 | 6 | secondary |
| Styler: gel | 9 | 6% | 16 | 8 | secondary |
| Heat protectant | 7 | 5% | 24 | 13 | secondary |
| Styler: curl cream | 5 | 5% | 18 | 12 | secondary |
| Styler: hairspray | 5 | 5% | 12 | 7 | secondary |
| Co-wash | 4 | 4% | 18 | 12 | secondary |
| Finisher: shine spray | 4 | 6% | 21 | 11 | secondary |
| Scalp treatment | 4 | 2% | 20 | 18 | secondary |
| Styler: smoothing cream | 4 | 7% | 32 | 32 | secondary |
| Styler: lotion | 3 | 25% | 10 | 8 | secondary |
| Styler: paste | 3 | 3% | 16 | 12 | secondary |
| Styler: texture spray | 3 | 5% | 15 | 13 | secondary |
| Styler: volumizer | 3 | 4% | 30 | 16 | secondary |
| Finisher: oil | 2 | 1% | 29 | 21 | secondary |
| Finisher: serum | 2 | 2% | 23 | 19 | secondary |
| Styler: edge control | 2 | 13% | 22 | 19 | secondary |
| Finisher: end oil | 1 | 11% | 18 | 18 | secondary |
| Styler: refresh spray | 1 | 8% | 11 | 11 | secondary |
No product-type differences have been researched yet — the reading below is computed from where it sits on the labels in our library.
Position footprint
Every listing in our library, by position on the label.
| Positions | Zone | Listings |
|---|---|---|
| 1-3 | Leading | 4 |
| 4-8 | Supporting | 21 |
| 9-15 | Secondary | 86 |
| 16-25 | Lower | 138 |
| 26+ | Trace | 128 |
How to read this
US labelling rules put ingredients above 1% in descending order of amount; below 1% they may be listed in any order.
So position tells you about relative amount only above that line, and we never convert a position into a percentage.
Why it matters to shoppers
What this ingredient is evidence of, what it is not evidence of, and what our own method can and cannot tell you.
- a product that keeps over its shelf life
- a rinse-clean feel
- an exact safety score — we do not publish one, for any ingredient
- how a finished product performs by itself — that is the whole formula, not one line of it
- the exact percentage in a bottle — label position never converts into a number
- a secondary preservative, listed below the main ingredients in our shampoos
- it was on the label of every product we counted — we read printed ingredient lists, not marketing copy
- that the product would be better without one
- that a product is right or wrong for you
We do not publish safety scores or hazard grades. Where a regulator has published a restriction or a use condition, we state it and cite it; otherwise we describe what the ingredient does and stop.
Commonly paired with
Ingredients that appear alongside this one most often in our library. Near-universal ingredients are excluded — they pair with everything and tell you nothing.
- Benzyl Alcohol · 100
- Cetrimonium Chloride · 97
- Glycereth-2 Cocoate · 95
- Behentrimonium Chloride · 95
- Sodium Chloride · 85
- Tocopherol · 82
- Propylene Glycol · 80
- Caprylyl Glycol · 80
- Aloe Barbadensis Leaf Juice · 78
- Cocamidopropyl Betaine · 76
The number beside a name is how many products in our library list both.
These ingredients tend to appear together to carry the formula and let it dry, improve feel after rinsing, and clean and build foam.
Found in these products
The most prominent placements first. The badge is the position on that product’s own ingredient list.
amika · Shampoo
Bust Your Brass Cool Blonde Strength Repair Shampoo
#2 on the label · $3.15/oz
Carol's Daughter · Shampoo
Born To Repair Sulfate Free Nourishing Shampoo
#2 on the label · $1.27/oz
Pureology · Shampoo
Pureology Pure Volume Shampoo
#2 on the label · $2.37/oz
Pureology · Shampoo
Pureology Hydrate Shampoo
#5 on the label · $2.51/oz
Design Essentials · Conditioner
Agave & Lavender Moisturizing & Detangling Conditioner
#6 on the label · $1.04/oz
ORS · Styler
Olive Oil Curlshow Curl Style Mousse
#6 on the label · $1.43/oz
Design Essentials · Shampoo
Almond & Avocado Moisturizing & Detangling Sulfate-Free Shampoo
#7 on the label · $1.08/oz
Design Essentials · Leave-in
Kukui & Coconut Hydrating Leave-In Conditioner
#7 on the label · $1.08/oz
got2b · Styler
Glued Blasting Freeze Hairspray
#7 on the label · $0.60/oz
Design Essentials · Leave-in
Almond & Avocado Moisturizing & Detangling Leave-In Conditioner
#8 on the label · $1.17/oz
Design Essentials · Styler
Almond & Avocado Twist & Set Setting Lotion
#8 on the label · $1.87/oz
Identity
What this entry is, and what our references call it.
Benzoic Acid
- CAS 65-85-0
- PubChem 243
- benzoic acid
For your hair?
Whether Benzoic Acid matters for your hair depends on your hair.
the 4th most-listed preservative or antioxidant in our libraryWhat this ingredient does, and where it sits on the labels we have researched.
A verdict on any product that contains it, and never a safety grade.
We do not physically test your hair. Everything above is read from the ingredient lists in our library and from published references — the consultation is what turns it into a plan.
References
Sourced Backed by a manufacturer or regulatory source.
This ingredient
- Manufacturer or regulatory PubChem — Compound identity: CID 243, CAS 65-85-0, C7H6O2 · accessed 2026-08-28
How this page was made
- Every number above is counted from the ingredient lists in our own product library — 314 of 4008 researched products list this ingredient. Nothing on this page is written per ingredient.
- The dots are levels, not scores. Each one is read from what kind of ingredient it is — its chemical class, its charge, its solubility — or from where it sits on the labels we have.
- US labelling rules put ingredients above 1% in descending order of amount; below 1% they may be listed in any order. Position tells you about relative amount only above that line, and we never convert a position into a percentage.
- The prominence bands (leading, supporting, secondary) are the same ones the product pages use to read a single label, applied here to the median position across a category.
- We do not publish safety scores or hazard grades. Where a regulator has published a restriction or a use condition, we state it and cite it; otherwise we describe what the ingredient does and stop.
- Identifiers and references appear only when a published source is attached to this entry; where none is, the row is simply absent rather than filled in.
- This is cosmetic information, not medical advice, and nothing here diagnoses or treats a health condition.
- Entry last updated 2026-08-28. Product-page methodology: the product library.