SOLVENT
Propylene Glycol
- solvent
A small humectant and solvent that keeps formulas stable and helps active ingredients spread.
- products in our library
- 1245
- of researched products
- 18%
- on the label, in our shampoos
- usually #17
- 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.
How fast it leaves after the product is applied.
What is still on the hair once it has evaporated.
| Property | Level | Out of |
|---|---|---|
| Buildup risk | Low | 1 of 5 |
| Rinse-out behaviour | Rinses clean | 5 of 5 |
| Drying speed | Steady | 2 of 5 |
| Residue | Minimal | 2 of 5 |
What it does for a formula
What Propylene Glycol does
The general function first, then how the role changes by product type where we have researched it.
What everything else is dissolved in before it reaches your hair.
Binds water and holds it against the hair rather than adding oil.
What a humectant does depends on the air around it as much as on the formula.
Water alone removes it, so it does not accumulate between washes.
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, so it does not build up 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
260 products
|
secondary · #17 | |
Conditioner
191 products
|
secondary · #15 | |
Leave-in
168 products
|
supporting · #7 | |
Mask / treatment
128 products
|
secondary · #12 | |
Styler: paste
69 products
|
supporting · #6 | |
Styler: gel
67 products
|
supporting · #5 | |
Styler: mousse
54 products
|
secondary · #9 | |
Heat protectant
44 products
|
supporting · #8 | |
Scalp treatment
41 products
|
secondary · #14 | |
Styler: curl cream
38 products
|
supporting · #6 |
16 more product types
| Product type | How common | Typical position on label ? |
|---|---|---|
Styler: hairspray
28 products
|
secondary · #13 | |
Styler: volumizer
24 products
|
supporting · #7 | |
Styler: edge control
19 products
|
supporting · #6 | |
Styler: smoothing cream
17 products
|
supporting · #7 | |
Finisher: serum
15 products
|
supporting · #5 | |
Finisher: shine spray
15 products
|
supporting · #6 | |
Styler: texture spray
15 products
|
supporting · #5 | |
Finisher: oil
11 products
|
secondary · #13 | |
Styler: lotion
9 products
|
supporting · #6 | |
Co-wash
8 products
|
secondary · #20 | |
Styler: refresh spray
8 products
|
leading · #3 | |
Finisher: anti frizz finish
7 products
|
secondary · #10 | |
Dry shampoo
5 products
|
secondary · #17 | |
Relaxer
2 products
|
secondary · #11 | |
Finisher: end oil
1 product
|
supporting · #4 | |
Lightener
1 product
|
secondary · #10 |
| Product type | Products | Share of category | Median position | Earliest position | Band |
|---|---|---|---|---|---|
| Shampoo | 260 | 17% | 17 | 2 | secondary |
| Conditioner | 191 | 17% | 15 | 2 | secondary |
| Leave-in | 168 | 24% | 7 | 2 | supporting |
| Mask / treatment | 128 | 22% | 12 | 1 | secondary |
| Styler: paste | 69 | 35% | 6 | 2 | supporting |
| Styler: gel | 67 | 25% | 5 | 1 | supporting |
| Styler: mousse | 54 | 27% | 9 | 2 | secondary |
| Heat protectant | 44 | 21% | 8 | 1 | supporting |
| Scalp treatment | 41 | 14% | 14 | 2 | secondary |
| Styler: curl cream | 38 | 17% | 6 | 2 | supporting |
| Styler: hairspray | 28 | 12% | 13 | 2 | secondary |
| Styler: volumizer | 24 | 17% | 7 | 2 | supporting |
| Styler: edge control | 19 | 50% | 6 | 3 | supporting |
| Styler: smoothing cream | 17 | 21% | 7 | 2 | supporting |
| Finisher: serum | 15 | 11% | 5 | 1 | supporting |
| Finisher: shine spray | 15 | 15% | 6 | 1 | supporting |
| Styler: texture spray | 15 | 15% | 5 | 2 | supporting |
| Finisher: oil | 11 | 4% | 13 | 2 | secondary |
| Styler: lotion | 9 | 25% | 6 | 2 | supporting |
| Co-wash | 8 | 8% | 20 | 8 | secondary |
| Styler: refresh spray | 8 | 23% | 3 | 2 | leading |
| Finisher: anti frizz finish | 7 | 22% | 10 | 2 | secondary |
| Dry shampoo | 5 | 4% | 17 | 14 | secondary |
| Relaxer | 2 | 50% | 11 | 6 | secondary |
| Finisher: end oil | 1 | 13% | 4 | 4 | supporting |
| Lightener | 1 | 33% | 10 | 10 | secondary |
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 | 217 |
| 4-8 | Supporting | 287 |
| 9-15 | Secondary | 294 |
| 16-25 | Lower | 311 |
| 26+ | Trace | 136 |
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.
Light and water-binding rather than oily, so it adds less weight than oils or butters do.
A small water-binding solvent. It holds moisture and helps the rest of the formula spread evenly over the strand.
A humectant follows the air: it holds water in humid conditions and can give it up in very dry ones. Climate decides what it does more than the label does.
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.
- a light, fast-drying formula
- hydration rather than oil
- a rinse-clean feel
- body without weight on fine hair
- 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 solvent, listed below the main ingredients in our shampoos
- it was on the printed ingredient list of every product we counted (we read labels, 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
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.
- Hexyl Cinnamal · 385
- Ethylhexylglycerin · 379
- Benzyl Alcohol · 371
- Behentrimonium Chloride · 331
- Cetrimonium Chloride · 320
- Citronellol · 304
- Disodium EDTA · 288
- Sodium Hydroxide · 273
- Sodium Chloride · 270
- Caprylyl Glycol · 259
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, 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.
Color Wow · Finisher
Pop & Lock Frizz Control & Glossing Serum
#1 on the label · $13.33/oz
Color Wow · Finisher
Pop & Lock High Gloss Finish
#1 on the label · $13.33/oz
Davines · Mask / treatment
OI Liquid Luster
#1 on the label · $5.62/oz
Garnier Fructis · Finisher
Whole Blends Hair Honey Repairing Serum
#1 on the label · $1.86/oz
Joico · Mask / treatment
Defy Damage In A Flash 7-Second Bond Builder
#1 on the label · $4.73/oz
L'Oreal Paris · Mask / treatment
Elvive 8 Second Wonder Water Lamellar Hair Treatment
#1 on the label · $1.62/oz
L'Oreal Paris · Mask / treatment
Elvive Dream Lengths 8 Second Wonder Water Lamellar Rinse-Out
#1 on the label · $1.62/oz
L'Oreal Paris · Mask / treatment
Elvive Hyaluron Plump Flash Hydration Wonder Water
#1 on the label · $1.62/oz
One 'n Only · Finisher
Shiny Silver Ultra Shine Spray
#1 on the label · $2.50/oz
Paul Mitchell · Styler
Straight Works Serum Gel
#1 on the label · $5.10/oz
Rusk · Heat protectant
Blow Dry Balm
#1 on the label · $5.25/oz
African Pride · Styler
Moisture Restore Curl Refresher
#2 on the label · $0.83/oz
See all 1245 products in the library that list Propylene Glycol
Identity
What this entry is, and what our references call it.
Propylene Glycol
- CAS 57-55-6
- PubChem 1030
- humectant
- propylene glycol
- propylene glycol (1,2-propanediol)
- propylene glycon
For your hair?
Whether Propylene Glycol matters for your hair depends on your hair.
the 3rd most-listed solvent or propellant 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 comes 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 1030, CAS 57-55-6, C3H8O2 · accessed 2026-08-28
How this page was made
- Every number above is counted from the ingredient lists in our own product library: 1245 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.
