EMULSIFIER
PEG-40 Hydrogenated Castor Oil
- emulsifier
A castor-oil derivative that dissolves fragrance and oils into water so the product stays clear and does not separate.
- products in our library
- 262
- of researched products
- 7%
- on the label, in our leave-ins
- usually #8
- most common in
- Leave-in
- 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.
How much oil it strips, as a class.
The foam the class is known for, not a measured volume.
| Property | Level | Out of |
|---|---|---|
| Buildup risk | Low | 1 of 5 |
| Rinse-out behaviour | Rinses clean | 5 of 5 |
| Cleansing strength | Not a cleanser | 1 of 5 |
| Lather | Little | 1 of 5 |
What it does for a formula
What PEG-40 Hydrogenated Castor Oil does
The general function first, then how the role changes by product type where we have researched it.
How a clear liquid can carry an oil or a fragrance without going cloudy.
Without one, a cream separates in the bottle.
Water alone removes it, so it does not accumulate between washes.
Hair neither pulls it in nor pushes it away.
Charge
Carries no charge, so it neither clings to hair nor is pushed away by it. Nonionic ingredients are the mild, pH-tolerant workhorses of a formula.
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 ? |
|---|---|---|
Leave-in
40 products
|
supporting · #8 | |
Styler: gel
35 products
|
supporting · #6 | |
Styler: mousse
33 products
|
supporting · #8 | |
Shampoo
25 products
|
secondary · #14 | |
Styler: paste
24 products
|
supporting · #7 | |
Heat protectant
17 products
|
supporting · #6 | |
Scalp treatment
17 products
|
supporting · #8 | |
Mask / treatment
15 products
|
secondary · #12 | |
Conditioner
12 products
|
secondary · #18 | |
Styler: volumizer
10 products
|
supporting · #9 |
11 more product types
| Product type | How common | Typical position on label ? |
|---|---|---|
Co-wash
5 products
|
secondary · #19 | |
Finisher: shine spray
4 products
|
supporting · #7 | |
Styler: curl cream
4 products
|
secondary · #18 | |
Styler: edge control
4 products
|
supporting · #6 | |
Styler: hairspray
4 products
|
secondary · #10 | |
Styler: texture spray
4 products
|
supporting · #7 | |
Finisher: anti frizz finish
3 products
|
secondary · #12 | |
Finisher: serum
3 products
|
supporting · #4 | |
Styler: refresh spray
2 products
|
secondary · #11 | |
Finisher: oil
1 product
|
supporting · #4 | |
Styler: smoothing cream
1 product
|
supporting · #6 |
| Product type | Products | Share of category | Median position | Earliest position | Band |
|---|---|---|---|---|---|
| Leave-in | 40 | 9% | 8 | 2 | supporting |
| Styler: gel | 35 | 22% | 6 | 3 | supporting |
| Styler: mousse | 33 | 24% | 8 | 2 | supporting |
| Shampoo | 25 | 3% | 14 | 3 | secondary |
| Styler: paste | 24 | 27% | 7 | 2 | supporting |
| Heat protectant | 17 | 12% | 6 | 3 | supporting |
| Scalp treatment | 17 | 11% | 8 | 3 | supporting |
| Mask / treatment | 15 | 4% | 12 | 3 | secondary |
| Conditioner | 12 | 2% | 18 | 6 | secondary |
| Styler: volumizer | 10 | 15% | 9 | 4 | supporting |
| Co-wash | 5 | 5% | 19 | 4 | secondary |
| Finisher: shine spray | 4 | 6% | 7 | 4 | supporting |
| Styler: curl cream | 4 | 4% | 18 | 5 | secondary |
| Styler: edge control | 4 | 25% | 6 | 4 | supporting |
| Styler: hairspray | 4 | 4% | 10 | 4 | secondary |
| Styler: texture spray | 4 | 7% | 7 | 6 | supporting |
| Finisher: anti frizz finish | 3 | 13% | 12 | 6 | secondary |
| Finisher: serum | 3 | 4% | 4 | 2 | supporting |
| Styler: refresh spray | 2 | 15% | 11 | 8 | secondary |
| Finisher: oil | 1 | 1% | 4 | 4 | supporting |
| Styler: smoothing cream | 1 | 2% | 6 | 6 | supporting |
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 | 37 |
| 4-8 | Supporting | 131 |
| 9-15 | Secondary | 88 |
| 16-25 | Lower | 36 |
| 26+ | Trace | 32 |
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 clear formula that still carries oils
- a stable cream that does not separate
- 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 supporting solubiliser alongside the main ingredients in our leave-ins
- it was on the label of every product we counted — we read printed ingredient lists, not marketing copy
- 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.
- Citronellol · 83
- Propylene Glycol · 78
- Hexyl Cinnamal · 74
- Benzyl Alcohol · 74
- Butylene Glycol · 73
- Cetrimonium Chloride · 71
- Disodium EDTA · 68
- Caprylyl Glycol · 67
- Tocopherol · 60
- Benzyl Salicylate · 56
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, carry the formula and let it dry, and improve feel after rinsing.
Found in these products
The most prominent placements first. The badge is the position on that product’s own ingredient list.
Aunt Jackie's · Finisher
Curl La La Bounce Back Refreshing Serum
#2 on the label · $2.00/oz
Axe · Styler
Axe Signature Clean Cut Look Hair Classic Pomade
#2 on the label · $3.03/oz
Cantu · Leave-in
Kids Conditioning Detangler
#2 on the label · $0.67/oz
Carol's Daughter · Leave-in
Black Vanilla Moisture & Shine Leave-In Conditioner
#2 on the label · $1.57/oz
Creme of Nature · Styler
Hair Food Smoothing & Frizz Control Styling Mousse
#2 on the label · $0.87/oz
Creme of Nature · Leave-in
Pure Honey Scalp Refresh Invigorating Leave-In
#2 on the label · $0.85/oz
got2b · Styler
Curled Flexible Curl Foam
#2 on the label · $1.64/oz
IGK · Leave-in
Mixed Feelings Leave-In Blonde Toning Drops
#2 on the label · $29.00/oz
Kevin Murphy · Leave-in
Staying.Alive
#2 on the label · $6.77/oz
Redken · Styler
Brews Cream Pomade
#2 on the label · $7.06/oz
Redken · Styler
Brews Molding Paste
#2 on the label · $4.80/oz
Redken · Styler
Texture Paste
#2 on the label · $8.24/oz
See all 262 products in the library that list PEG-40 Hydrogenated Castor Oil
Identity
What this entry is, and what our references call it.
No public-domain structure depiction is available for this entry.
PEG-40 Hydrogenated Castor Oil
- solubilizer
- peg-40 hydrogenated castor oil
For your hair?
Whether PEG-40 Hydrogenated Castor Oil matters for your hair depends on your hair.
the 3rd most-listed cleanser or emulsifier 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
Seed entry — sourcing in progress Written from our reference work; primary sourcing is still being attached.
No published source is attached to this entry yet.
How this page was made
- Every number above is counted from the ingredient lists in our own product library — 262 of 3928 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.