PROTEIN
Quaternium-33
- protein
A lanolin-derived conditioning agent used for slip and a soft, coated feel. Animal-derived.
- products in our library
- 19
- of researched products
- 0.3%
- on the label, in our leave-ins
- usually #23
- most common in
- Leave-in
- in water
- Water-dispersible
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.
Smaller fragments travel further into the strand.
Read from where it sits on the labels we have, not from the molecule.
| Property | Level | Out of |
|---|---|---|
| Buildup risk | Low | 2 of 5 |
| Rinse-out behaviour | Stays where hair is damaged | 2 of 5 |
| Fragment size | Large | 4 of 5 |
| Stiffening potential | Slight | 2 of 5 |
What it does for a formula
What Quaternium-33 does
The general function first, then how the role changes by product type where we have researched it.
Sticks to damaged areas of the surface and temporarily firms them.
Welcome on limp or damaged hair, unwelcome on hair that already feels rigid.
Positive charge is drawn to the negatively charged, worn patches of a strand.
The measurable part of conditioning: less force to pull a comb through.
Charge
Positively charged, so it is drawn to the negatively charged, damaged areas of hair and stays behind after rinsing. That is why conditioning happens where the wear is.
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 ? |
|---|---|---|
Leave-in
5 products
|
secondary · #23 | |
Mask / treatment
5 products
|
secondary · #15 | |
Heat protectant
3 products
|
secondary · #19 | |
Shampoo
3 products
|
secondary · #17 | |
Conditioner
2 products
|
secondary · #24 | |
Finisher: serum
1 product
|
supporting · #8 |
| Product type | Products | Share of category | Median position | Earliest position | Band |
|---|---|---|---|---|---|
| Leave-in | 5 | 1% | 23 | 8 | secondary |
| Mask / treatment | 5 | 1% | 15 | 15 | secondary |
| Heat protectant | 3 | 1% | 19 | 8 | secondary |
| Shampoo | 3 | 0% | 17 | 16 | secondary |
| Conditioner | 2 | 0% | 24 | 16 | secondary |
| Finisher: serum | 1 | 1% | 8 | 8 | supporting |
We have not researched differences by product type yet. The reading below comes 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 | 3 |
| 9-15 | Secondary | 3 |
| 16-25 | Lower | 10 |
| 26+ | Trace | 3 |
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
Formulation guidance for specific hair conditions, limited to the label positions where it applies. It is not a conclusion about any finished product, or about you.
A cationic conditioning agent: it binds to the damaged, negatively charged parts of the cuticle and lowers combing friction there.
Substantive by design. A routine with no detergent wash gives it nothing to leave with.
Detangling and weight come from the same deposit; how much of each depends on the chain length of the specific conditioner.
Read where it is listed in the first three ingredients or positions 4–8.Unhydrolysed protein is too large to enter the strand. It sits on the surface, which is a coating effect rather than internal reinforcement.
A large surface-depositing protein. If protein reliably makes your hair feel rigid, this is the form most likely to do it.
Read where it is listed in the first three ingredients or positions 4–8.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 seeing this ingredient tells you, what it does not, and the limits of our own method.
- detangling
- thick or coarse hair
- temporary strength on damaged hair
- detangling and less breakage from combing
- an exact safety score (we do not publish one for any ingredient)
- how a finished product performs, which depends on the whole formula, not one line of it
- the exact percentage in a bottle, because label position never converts into a number
- a secondary protein, listed below the main ingredients in our leave-ins
- it was on the printed ingredient list of every product we counted (we read labels, not marketing copy)
- it is meant to stay on the hair rather than rinse away
- stiffness (that depends on how much of it there is)
- 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
The ingredients that most often appear alongside this one in our library. We leave out the near-universal ones, because they pair with everything and tell you nothing.
- Behentrimonium Methosulfate · 15
- Cetyl Alcohol · 14
- Propylene Glycol · 10
- Behentrimonium Chloride · 10
- Citronellol · 9
- Tocopherol · 8
- Benzyl Alcohol · 8
- 2-Oleamido-1,3-Octadecanediol · 7
- Dipropylene Glycol · 7
- Sodium Hyaluronate · 7
The number beside a name is how many products in our library list both.
These ingredients tend to appear together to improve feel after rinsing, soften the strand, and carry the formula and let it dry.
Found in these products
The most prominent placements first. The badge is the position on that product’s own ingredient list.
Kerastase · Finisher
Blond Absolu Cicaplasme Serum
#8 on the label · $8.63/oz
Kerastase · Heat protectant
Blond Absolu Cicaplasme Thermique Heat Protecting Cream
#8 on the label · $9.86/oz
L'Oreal Professionnel · Leave-in
[Pro Longer] Renewing Cream
#8 on the label · $6.03/oz
LADOR · Mask / treatment
Perfumed Hair Treatment [Hinoki]
#15 on the label · $3.42/oz
LADOR · Mask / treatment
Perfumed Hair Treatment [La pitta]
#15 on the label · $3.42/oz
LADOR · Mask / treatment
Perfumed Hair Treatment [Osmanthus]
#15 on the label · $3.42/oz
Color Wow · Leave-in
Flo-etry Vital Natural Serum for Curly Hair
#16 on the label · $5.00/oz
Leonor Greyl · Shampoo
Shampooing Reviviscence
#16 on the label · $12.20/oz
Redken · Conditioner
Extreme Conditioner
#16 on the label · $2.72/oz
Redken · Shampoo
Extreme Shampoo
#17 on the label · $2.87/oz
Kerastase · Heat protectant
Resistance Ciment Thermique
#19 on the label · $9.90/oz
Kerastase · Heat protectant
Resistance Heat Protectant Leave-In Styling Cream for Damaged Hair
#19 on the label · $9.80/oz
Identity
What this entry is, and what our references call it.
No public-domain structure depiction is available for this entry.
Quaternium-33
- conditioning agent
- quaternium 33
- quaternium-33
For your hair?
Whether Quaternium-33 matters for your hair depends on your hair.
19 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 comes 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: 19 of 6816 researched products list this ingredient. Nothing on this page is written per ingredient.
- The dots are levels, not scores. Each one comes from what kind of ingredient it is (its chemical class, charge and 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. Without one, we leave the row out rather than fill it in.
- This is cosmetic information, not medical advice, and nothing here diagnoses or treats a health condition.
- Entry last updated 2026-09-22. Product-page methodology: the product library.
