PRESERVATIVE
Caprylhydroxamic Acid
- preservative
A coconut-derived preservative booster that also binds trace metals.
- products in our library
- 62
- of researched products
- 2%
- on the label, in our shampoos
- usually #17
- most common in
- Shampoo
- in water
- Water-dispersible
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 | 2 of 5 |
| Rinse-out behaviour | Rinses with shampoo | 4 of 5 |
| Role | Keeps water-based formulas | 4 of 5 |
| Prominence | Secondary | 2 of 5 |
What it does for a formula
What Caprylhydroxamic 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.
Stops calcium and iron in tap water dulling a wash.
It does not truly dissolve, and ordinary shampooing removes it.
Charge
Charge is not recorded for this ingredient.
Solubility
Spreads through water without truly dissolving, and normal shampooing removes it.
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
15 products
|
secondary · #17 | |
Conditioner
14 products
|
secondary · #20 | |
Leave-in
11 products
|
secondary · #17 | |
Mask / treatment
6 products
|
secondary · #25 | |
Scalp treatment
5 products
|
secondary · #19 | |
Styler: mousse
4 products
|
secondary · #14 | |
Co-wash
2 products
|
secondary · #15 | |
Styler: gel
2 products
|
secondary · #12 | |
Styler: curl cream
1 product
|
secondary · #14 | |
Styler: hairspray
1 product
|
secondary · #22 |
1 more product type
| Product type | How common | Typical position on label ? |
|---|---|---|
Styler: smoothing cream
1 product
|
secondary · #29 |
| Product type | Products | Share of category | Median position | Earliest position | Band |
|---|---|---|---|---|---|
| Shampoo | 15 | 2% | 17 | 7 | secondary |
| Conditioner | 14 | 2% | 20 | 4 | secondary |
| Leave-in | 11 | 3% | 17 | 9 | secondary |
| Mask / treatment | 6 | 2% | 25 | 5 | secondary |
| Scalp treatment | 5 | 3% | 19 | 12 | secondary |
| Styler: mousse | 4 | 3% | 14 | 11 | secondary |
| Co-wash | 2 | 2% | 15 | 14 | secondary |
| Styler: gel | 2 | 1% | 12 | 11 | secondary |
| Styler: curl cream | 1 | 1% | 14 | 14 | secondary |
| Styler: hairspray | 1 | 1% | 22 | 22 | secondary |
| Styler: smoothing cream | 1 | 2% | 29 | 29 | 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 | 7 |
| 9-15 | Secondary | 26 |
| 16-25 | Lower | 29 |
| 26+ | Trace | 13 |
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.
Who should pay attention
Conditional formulation guidance, scoped to a hair condition and to the positions where it is meaningful. It is not a conclusion about any finished product, and not a conclusion about you.
Binds the calcium and magnesium in hard water, which is what stops mineral deposits accumulating on the strand wash after wash.
Copper and iron carried in tap water deposit on the strand and read as a dull, warm cast on gray or light hair. A chelator holds those metals in solution so the wash carries them off.
Read from this ingredient’s chemical class. Where we have researched the ingredient itself, that reading replaces the class one.
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 formula built for hard water
- a product that keeps over its shelf life
- a product ordinary shampooing removes
- a routine that does not build up
- 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.
- Caprylyl Glycol · 34
- Propanediol · 22
- Aloe Barbadensis Leaf Juice · 22
- Benzyl Alcohol · 19
- Simmondsia Chinensis (Jojoba) Seed Oil · 18
- Behentrimonium Chloride · 16
- Butyrospermum Parkii (Shea) Butter · 14
- Sodium Hydroxide · 14
- Cocos Nucifera (Coconut) Oil · 14
- Lactic Acid · 13
The number beside a name is how many products in our library list both.
These ingredients tend to appear together to hold on to water, carry the formula and let it dry, and give the formula body and hold.
Found in these products
The most prominent placements first. The badge is the position on that product’s own ingredient list.
Original Sprout · Mask / treatment
Luscious Island Masque
#5 on the label · $6.66/oz
Mixed Chicks · Shampoo
Gentle Clarifying Shampoo
#7 on the label · $1.00/oz
Mixed Chicks · Shampoo
His Mix Shine-Starter Clarifying Shampoo
#7 on the label · $1.17/oz
Rahua · Styler
Aloe Vera Hair Gel
#7 on the label · $9.55/oz
Melanin Haircare · Conditioner
Plumping Deep Conditioner
#8 on the label · $3.00/oz
Rahua · Styler
Aloe Vera Hair Mousse
#8 on the label · $11.52/oz
Hairstory · Mask / treatment
Pre-Wash
#9 on the label · $5.88/oz
Honest · Leave-in
Conditioning Sweet Cream Hair Detangler Spray
#9 on the label · $1.87/oz
Melanin Haircare · Leave-in
Multi-Use Softening Leave In Conditioner
#9 on the label · $2.25/oz
Hairstory · Leave-in
Primer
#10 on the label · $4.50/oz
Mixed Chicks · Conditioner
Kids Conditioner
#10 on the label · $1.38/oz
See all 62 products in the library that list Caprylhydroxamic Acid
Identity
What this entry is, and what our references call it.
Caprylhydroxamic Acid
- CAS 7377-03-9
- PubChem 23846
- hard-water chelator
- caprylhydroxamic acid
- caprylhydroxamic acid (coconut-based preservative)
For your hair?
Whether Caprylhydroxamic Acid matters for your hair depends on your hair.
62 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 23846, CAS 7377-03-9, C8H17NO2 · accessed 2026-08-28
How this page was made
- Every number above is counted from the ingredient lists in our own product library — 62 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.