PRESERVATIVE
Hydroxyacetophenone
- preservative
A preservative booster that also protects the formula from oxidising.
- products in our library
- 54
- of researched products
- 1%
- on the label, in our shampoos
- usually #21
- most common in
- Shampoo
- in water
- Water-soluble
At a glance
Four named levels, read from this ingredient’s chemical class, its charge, its solubility, or where it sits on the labels we have. More dots means more of the property named — never “better”.
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 Hydroxyacetophenone 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.
Protects the oils in the bottle rather than the hair.
Water alone removes it, so it does not accumulate between washes.
Charge
Charge is not recorded for this ingredient.
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
21 products
|
secondary · #21 | |
Conditioner
8 products
|
secondary · #21 | |
Leave-in
6 products
|
secondary · #18 | |
Mask / treatment
5 products
|
secondary · #32 | |
Finisher: serum
3 products
|
secondary · #22 | |
Styler: smoothing cream
3 products
|
secondary · #23 | |
Styler: gel
2 products
|
secondary · #15 | |
Co-wash
1 product
|
supporting · #4 | |
Heat protectant
1 product
|
secondary · #11 | |
Styler: curl cream
1 product
|
supporting · #8 |
3 more product types
| Product type | How common | Typical position on label ? |
|---|---|---|
Styler: mousse
1 product
|
secondary · #26 | |
Styler: paste
1 product
|
secondary · #25 | |
Styler: texture spray
1 product
|
secondary · #14 |
| Product type | Products | Share of category | Median position | Earliest position | Band |
|---|---|---|---|---|---|
| Shampoo | 21 | 3% | 21 | 8 | secondary |
| Conditioner | 8 | 1% | 21 | 10 | secondary |
| Leave-in | 6 | 1% | 18 | 12 | secondary |
| Mask / treatment | 5 | 1% | 32 | 11 | secondary |
| Finisher: serum | 3 | 4% | 22 | 9 | secondary |
| Styler: smoothing cream | 3 | 5% | 23 | 17 | secondary |
| Styler: gel | 2 | 1% | 15 | 12 | secondary |
| Co-wash | 1 | 1% | 4 | 4 | supporting |
| Heat protectant | 1 | 1% | 11 | 11 | secondary |
| Styler: curl cream | 1 | 1% | 8 | 8 | supporting |
| Styler: mousse | 1 | 1% | 26 | 26 | secondary |
| Styler: paste | 1 | 1% | 25 | 25 | secondary |
| Styler: texture spray | 1 | 2% | 14 | 14 | 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 | 0 |
| 4-8 | Supporting | 4 |
| 9-15 | Secondary | 17 |
| 16-25 | Lower | 26 |
| 26+ | Trace | 16 |
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
- oils that do not turn rancid in the bottle
- 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.
- Hexyl Cinnamal · 31
- Guar Hydroxypropyltrimonium Chloride · 26
- Caprylyl Glycol · 26
- Propanediol · 22
- Sodium Hydroxide · 22
- Citronellol · 21
- Sodium Lauroyl Methyl Isethionate · 14
- Hydroxyethylcellulose · 14
- Glycol Distearate · 14
- Propylene Glycol · 14
The number beside a name is how many products in our library list both.
These ingredients tend to appear together to give it a scent, improve feel after rinsing, and hold on to water.
Found in these products
The most prominent placements first. The badge is the position on that product’s own ingredient list.
Urban Hydration · Co-wash
Breath of Fresh Hair Kids Co-Wash & Conditioner
#4 on the label · $0.83/oz
Bondi Boost · Scalp treatment
Lock Drops Anti-Shedding Scalp & Hair Serum
#7 on the label · $30.00/oz
Goldwell · Styler
StyleSign Curls Defining Cream
#8 on the label · $4.75/oz
Selsun Blue · Shampoo
Medicated Maximum Strength Dandruff Shampoo
#8 on the label · $0.73/oz
UNITE Hair · Finisher
7SECONDS Detangler
#9 on the label · $6.16/oz
Christophe Robin · Shampoo
Colour Shield Shampoo with Camu-Camu Berries
#10 on the label · $3.90/oz
Kevin Murphy · Conditioner
KILLER.CURLS RINSE
#10 on the label · $4.38/oz
Christophe Robin · Mask / treatment
Colour Shield Conditioner with Camu Camu Berries
#11 on the label · $6.27/oz
Sexy Hair · Heat protectant
Style Prep Me 450F Heat Protection Blow Dry Primer
#11 on the label · $3.03/oz
Alterna Haircare · Shampoo
Caviar Anti-Aging Restructuring Bond Repair Shampoo
#12 on the label · $3.44/oz
American Crew · Styler
Fiber Grooming Foam
#12 on the label · $1.95/oz
Blind Barber · Styler
121 Proof Thickening Style Gel
#12 on the label · $9.60/oz
See all 54 products in the library that list Hydroxyacetophenone
Identity
What this entry is, and what our references call it.
Hydroxyacetophenone
- CAS 99-93-4
- PubChem 7469
- antioxidant
- hydroxyacetophenone
For your hair?
Whether Hydroxyacetophenone matters for your hair depends on your hair.
54 products in our library list itWhat 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 7469, CAS 99-93-4, C8H8O2 · accessed 2026-08-28
How this page was made
- Every number above is counted from the ingredient lists in our own product library — 54 of 3889 researched products list this ingredient. Nothing on this page is written per ingredient.
- The dots are named levels read from an ingredient’s chemical class, charge, solubility, or where it sits on the labels we have — never a score.
- 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.