Overnight Scalp Barrier Serum
Scalp treatment
- Scalp treatment
- Sulfate-free
- Silicone-free
Add it to your products. We’ll tell you if it’s ever recalled.
Manufacturer page: philipkingsley.com
Personal fit
Is this right for you?
Complete the consultation to see how well this product fits your hair and your goals. With 6,000+ products in our library, we can match you to the right ones.
- About 20 minutes, and your answers save as you go.
- Every product matched against your hair across the 19 factors we check.
- A personalized routine built around your schedule, styling habits, and local weather.
- Find products that do the same job at a lower cost.
- Your goals, scalp, damage history, water, budget, and scent preferences all shape your plan.
$49 with 60 days of follow-up questions and plan updates
$99 with 12 months. Pay once; the year renews only if you choose.
Show all 19 factors we check
The rest of what your plan weighs on this product.
The consultation builds your hair profile, checks every factor in this table against it, and tells you where this product fits or what to use instead.
Start your consultation$49 once, with 60 days of follow-up questions and plan updates. Nothing renews, and you never have to buy a product.
Your avoid-list
Same job for less elsewhere
$21.68/oz at 2.03 oz, more than 80% of the 280 scalp treatments , which mostly run $3.84–19.05/oz.
Great for
Maybe skip if
What the formula actually does
Read from the label, not the marketing
Each row says where it comes from: F means we derived it from this product’s own ingredient list, S means it is a claim the brand makes that the formula neither confirms nor contradicts.
Nothing here is built to reduce combing force.
Oils are present, but low enough to be a finishing touch.
Water-first and light: unlikely to flatten fine hair.
Humectants near the top: binding water is one of its main jobs.
No protein or amino acids in the list.
Nothing here needs a detergent wash to remove.
No chelating agent in the list.
No fragrance is listed.
Ingredients that matter
The ingredients that change a decision
The workhorse ingredients, plus anything lower down that changes a decision. The chips name what an ingredient does. They are not safety scores, and no ingredient here is rated good or bad on its own.
| Ingredient | What it does | Why it matters | Chip |
|---|---|---|---|
| Aloe Barbadensis Leaf Juice | humectant | Pulls water into the hair | Moisturizes |
| WaterAqua/Water/Eau | solvent | The base everything else is dissolved in | Neutral |
| Propanediol | humectant | Pulls water into the hair | Moisturizes |
| Betaine | humectant | Pulls water into the hair | Moisturizes |
| Polysorbate 20 | solubilizer | Keeps oils dissolved in water | Stabilizes |
| Lactic Acid | pH adjuster | Fine-tunes the pH | Moisturizes |
| Hamamelis Virginiana (Witch Hazel) Water | botanical extract | A trace plant extract | Neutral |
| Benzyl Alcohol | preservative | Keeps the product from spoiling | Stabilizes |
| Menthol | fragrance | The scent | Fragrance |
| Menthyl Lactate | fragrance | The scent | Fragrance |
| Piroctone Olamine | active | A secondary active | Active |
Full ingredient list (25)
In the US, ingredients above 1% are listed from most to least. Below 1% they can appear in any order. Each note keeps three things apart: what the ingredient generally does, its role in this type of product, and what its position can tell you.
-
1
Aloe Barbadensis Leaf Juice
General function
Aloe gel, used for light moisture and slip. High in the list it also contributes a little natural hold.
Leading ingredientListed in the first three ingredients, it is likely a structural part of this formula.
May suitCurls or waves needing flexible holdGums thicken and set soft, which gives definition that bends rather than a rigid cast.
May suitFine or easily flattened hairHydration with no oil attached, so it adds very little weight even high on a list.
May suitVery dry or highly damaged hairAloe is mostly water carrying sugars that bind more of it, which is why it turns up as the base of moisture-first formulas.
- humectant
- botanical extract
- gum
-
2
Water
· Aqua/Water/Eau
General function
The base of almost every rinse-off and cream hair product. It carries everything else and is normally the first ingredient on the label.
Leading ingredientListed in the first three ingredients, it is likely a structural part of this formula.
- solvent
-
3
Propanediol
General function
A corn-derived humectant and solvent, often chosen as a lighter-feeling alternative to propylene glycol.
Leading ingredientListed in the first three ingredients, it is likely a structural part of this formula.
PubChemMay suitFine or easily flattened hairLight and water-binding rather than oily, so it adds less weight than oils or butters do.
May suitVery dry or highly damaged hairA small water-binding solvent. It holds moisture and helps the rest of the formula spread evenly over the strand.
DependsClimate-sensitive or frizz-prone hairA 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.
- humectant
- solvent
-
4
Betaine
General function
A sugar-beet derived humectant that binds water. Despite the name it is not a cleanser like cocamidopropyl betaine.
Supporting ingredientListed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.
PubChemMay suitDry, coarse, or high-porosity hairHigh-porosity hair loses water fast; a humectant holds some of it in place for longer than the wash itself would.
May suitVery dry or highly damaged hairBinds water into the outer layers of the strand, and water is what makes dry hair flexible again rather than brittle.
DependsClimate-sensitive or frizz-prone hairA humectant moves water in whichever direction the air allows: it holds moisture in humid conditions and can pull it back out of hair in very dry ones.
- humectant
-
5
Polysorbate 20
General function
Keeps fragrance and oils dissolved in a watery formula so it stays clear.
Supporting ingredientListed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.
- solubilizer
- emulsifier
- ▾Below about here, the order stops meaning much. These are usually used at 1% or less.
-
6
Lactic Acid
General function
An acid used to set pH and, in scalp products, to loosen flakes.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
PubChemMay suitDry, coarse, or high-porosity hairHigh-porosity hair loses water fast; a humectant holds some of it in place for longer than the wash itself would.
May suitVery dry or highly damaged hairBinds water into the outer layers of the strand, and water is what makes dry hair flexible again rather than brittle.
DependsClimate-sensitive or frizz-prone hairA humectant moves water in whichever direction the air allows: it holds moisture in humid conditions and can pull it back out of hair in very dry ones.
- pH adjuster
- humectant
- exfoliant
-
7
Hamamelis Virginiana (Witch Hazel) Water
General function
Witch hazel water, used in scalp products for an astringent claim.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
- botanical extract
-
8
Benzyl Alcohol
General function
A preservative and solvent that also occurs naturally in some essential oils.
Estimated lower-concentration zonePubChemIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
- preservative
- solvent
-
9
Glycerin
General function
Glycerin, also called glycerol, attracts moisture and mixes completely with water.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
Scientific ReportsMay suitDry, coarse, or high-porosity hairHigh-porosity hair loses water fast; a humectant holds some of it in place for longer than the wash itself would.
May suitVery dry or highly damaged hairBinds water into the outer layers of the strand, and water is what makes dry hair flexible again rather than brittle.
DependsClimate-sensitive or frizz-prone hairWater moves both ways. Measured across concentrations, glycerin solutions give water up in some conditions and take it from the air in others. What it does for you depends on how much of it is there and on the air around it.
- humectant
-
10
Hexylene Glycol
General function
A solvent that keeps other ingredients dissolved and helps preservatives work.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
PubChemMay suitFine or easily flattened hairLight and water-binding rather than oily, so it adds less weight than oils or butters do.
May suitVery dry or highly damaged hairA small water-binding solvent. It holds moisture and helps the rest of the formula spread evenly over the strand.
DependsClimate-sensitive or frizz-prone hairA 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.
- solvent
- humectant
-
11
Saccharide Isomerate
- humectant
-
12
Capryloyl Glycine
General function
An amino-acid derivative used to support the preservative system and, in scalp products, for a clarifying claim.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
PubChemMay suitBuild-up-sensitive routinesCleansing is what lifts deposited films off the strand. How completely depends on which detergent it is and how high on the list it sits.
DependsVery dry or highly damaged hairEvery detergent removes some sebum along with the product it is there to wash out. Which detergent it is matters more than that there is one.
- preservative
- cleanser
-
13
Hydroxyethylcellulose
General function
A cellulose thickener that gives gels and conditioners their body and adds a soft, flexible film.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
PubChemMay suitCurls or waves needing flexible holdA polysaccharide film stays softer than a synthetic one as it dries, which is what leaves a curl defined but still able to move.
May suitFrizz-prone, damaged, or high-friction hairA soft film binds neighbouring strands together, which is most of what helps flyaways lie down.
May not suitMaximum-hold stylingGum films stay soft. A style that needs firm fixation usually wants a synthetic polymer doing the holding.
- gum
- thickener
- film former
-
14
Sodium Hydroxide
General function
A strong base used in trace amounts to raise pH; fully neutralised in the finished product.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
International Journal of TrichologyDependsFrizz-prone, damaged, or high-friction hairThe alkali half of a pH-adjusting pair, used in small amounts to bring a formula up to its target rather than to make it alkaline. Alkaline conditions raise the fibre's surface charge and lift the scales — but the finished pH is not on the label.
- pH adjuster
-
15
Menthol
General function
Produces the cooling, tingling feeling on the scalp. The sensation is real; it is not evidence that anything else is happening.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
PubChemMay not suitFragrance-sensitive routinesDeclared fragrance. On a fragrance-sensitive routine this is the line that decides it, wherever it sits on the label.
- fragrance
- active
-
16
Menthyl Lactate
General function
A gentler cooling agent than menthol, with less scent.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
PubChemMay not suitFragrance-sensitive routinesDeclared fragrance. On a fragrance-sensitive routine this is the line that decides it, wherever it sits on the label.
- fragrance
- active
-
17
Ethylhexylglycerin
General function
A preservative booster that also adds a little softness. Almost always paired with phenoxyethanol.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
PubChemMay suitFrizz-prone, damaged, or high-friction hairEmollients fill and smooth the surface of the strand, which lowers the friction that lifts the cuticle and reads as roughness.
- preservative
- emollient
-
18
Piroctone Olamine
- active
-
19
Sarcosine
General function
An amino acid derivative used for moisture binding and in scalp-positioned formulas.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
May suitVery dry or highly damaged hairAmino acids are the smallest protein fraction and bind water as well, so they add far less stiffness than a hydrolysed protein does.
DependsProtein-sensitive hairThe lightest option in the protein family, but still protein — worth watching if protein reliably stiffens your hair.
- amino acid
-
20
Xylitylglucoside
General function
A sugar-derived humectant used for lasting moisture without stickiness.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
PubChemMay suitDry, coarse, or high-porosity hairHigh-porosity hair loses water fast; a humectant holds some of it in place for longer than the wash itself would.
May suitVery dry or highly damaged hairBinds water into the outer layers of the strand, and water is what makes dry hair flexible again rather than brittle.
DependsClimate-sensitive or frizz-prone hairA humectant moves water in whichever direction the air allows: it holds moisture in humid conditions and can pull it back out of hair in very dry ones.
- humectant
-
21
Phenoxyethanol
- preservative
-
22
Avena Sativa (Oat) Kernel Oil
- oil
- emollient
-
23
Citric Acid
General function
Used to bring the product to a slightly acidic pH, which helps the cuticle lie flat. It is almost always near the end of the list.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
International Journal of TrichologyMay suitBuild-up-sensitive routinesHolds hard-water minerals in solution so they rinse away instead of depositing on the hair.
May suitFrizz-prone, damaged, or high-friction hairThe acid side of pH adjustment, and the reason it matters is measured: alkaline formulas raise the fibre's surface negative charge, increase friction between strands and lift the scales, while lower-pH ones do the reverse.
May suitGray, silver, or brass-prone hairWhere a warm cast comes from water minerals rather than from the hair itself, holding those metals in solution is what removes it.
- pH adjuster
- hard-water chelator
-
24
Sodium Citrate
General function
Used with citric acid to hold the formula at a steady, slightly acidic pH. It also binds a little hard-water mineral.
Estimated lower-concentration zoneIt appears around or below the estimated 1% line, where label order no longer indicates relative amount; its role may be minor or technical.
PubChemMay suitBuild-up-sensitive routinesBinds the calcium and magnesium in hard water, which is what stops mineral deposits accumulating on the strand wash after wash.
May suitGray, silver, or brass-prone hairCopper 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.
DependsFrizz-prone, damaged, or high-friction hairpH adjusters are how a formula is brought to a chosen acidity, and an acidic formula keeps the cuticle lying flatter than an alkaline one. Which way this one moves the pH depends on the formula, and the finished pH is not on the label.
- pH adjuster
- hard-water chelator
-
25
Tocopherol
- antioxidant
- vitamin
What the whole list adds up to
- 8 humectants
- 4 solvents
- 4 pH adjusters
- 4 preservatives
- 3 actives
- 2 botanical extracts
- 2 gums
- 2 fragrances
- 2 emollients
- 2 hard-water chelators
- 1 solubilizer
- 1 emulsifier
- 1 exfoliant
- 1 cleanser
Ingredient list captured 2026-10-07. Formulas change, so check the package in your hand when an ingredient matters to you.
Price · 2.03 oz
Priced above the products that do the same job. Stores sell it above the $7 line; products that do this job typically go for about $8 at this size.
Show the price ladder
Where we’ve seen it4 listings · 4 stores
-
Cult Beauty
$43.002.03 oz · $21.18/ozOct 8Lowest per oz
-
Philip Kingsley (brand site)
$44.002.03 oz · $21.68/ozOct 7
-
Philip Kingsley US
$44.002.03 oz · $21.68/ozOct 8
-
Dermstore
$44.002.03 oz · $21.68/ozOct 8
Sorted by price per ounce. Dated observations from our research, not live prices. Direct store pages, no affiliate links. We don’t sell this product.
How we work this out
- 2.03 oz is the size stores list most often; every comparison on this page is made at it. Other sizes are shown in the Sizes row and the store list.
- Commonly seen is the middle half of current prices for the 2.03 oz at recognised stores. We leave out the cheapest and most expensive quarters, so one sale or one overpriced listing can’t move it.
- Good value under $7 comes from the 8 products we score as doing the same job as this one. A quarter of them cost less than $3.21/oz; at 2.03 oz that is $7. Under that line you are paying less than most of them.
- About $8 is what those same products typically cost at this size: the midpoint of their prices per ounce, scaled to 2.03 oz.
Formula
It costs more per ounce than 80% of the 280 scalp treatments we’ve priced, the formula leaves out conditioning agents up front, and 8 close matches sell for at least a quarter less per ounce.
How the score is counted
- 8 products we score as doing the same job cost less per ounce
- Costs more per ounce than 80% of the 280 scalp treatments we’ve priced
- No conditioning agents up front in the formula
- No oils or butters in the working zone either
- Conditioning agents up frontWhat makes wet hair comb through.3 pts
- Oils or butters in the working zoneSoftens the strand rather than just coating it.2 pts
- Slip for detanglingReduces the force it takes to comb wet hair.2 pts
- A humectantBinds water into the hair.1 pt
- A pH adjusterBrings the formula to the acidic pH hair prefers.1 pt
- Fragrance kept out of the top eightScent as a finishing touch, not a major share.1 pt
The formula score measures completeness for the job: a weighted share of the systems this product type is usually built around that we find in this list. It does not rate how well the product works or its quality, and it never compares across product types.
Does the same job, for less
Formulas that do the same things (cleanse, condition, coat or hold) for less per ounce. Scent, texture and where you buy them can still differ.
- Protein-free
- Lightweight
- Silicone-free
- Function
- Also
- Protein-free
- Lightweight
- Silicone-free
- Function
- Also
- Protein-free
- Lightweight
- Silicone-free
- Function
- Also
See more alternatives in the product library
These products do a similar job. We haven’t matched them to you. Find the one that fits your hair, routine and budget
Final decision
Should you buy it?
Good for the right person, not the lowest costFlaking scalps who want an over-the-counter scalp active and a formula with no added fragrance
Not ideal for very dry or very humid climates, anyone who does not want a medicated product, or people shopping on a budget
We do not sell products or take placement fees. This page states what the formula and the prices show; the consultation is what matches it to a person.
More from Philip Kingsley
How this page was made
- Everything above comes from our researched product record: identity, the ingredient list as printed, the brand's own claims, dated prices and review themes our researchers wrote in their own words. No part of this page is written by hand for one product.
- The value band is a fixed label over two stored numbers: this product’s cost per ounce as a percentile of every product of this type we have priced, each at the size it is most often sold in, and how many products we score as doing the same job cost at least a quarter less per ounce.
- Both scores out of ten are defined on this page. The formula score is completeness for the job, computed from a fixed per-format checklist shown beneath the gauge; the price score is cost per ounce against every product of this type we have priced.
- The "Is this right for you?" panel reads only your own consultation answers, and it applies exactly the filters our recommendation engine applies. It is computed when you load the page and is never stored on it.
- 1 source consulted for this product (1 manufacturer or regulatory, 0 retailer, 0 editorial), last checked 2026-10-07.
- Ingredient references are linked for 14 of 16 product-aware annotations on this page. Fit notes are general formulation guidance. They aren’t a verdict on the finished product or on you.
- We haven’t tested this product in a lab, and we don’t physically test your hair. Formula readings come from the ingredient list. Claims about how it behaves are labelled as the brand's.
- Ingredient order tells you relative amount only above roughly 1%. Prices are what we saw on the dates shown and can change.
- Ingredient names link to our ingredient library, where each entry shows what it does, which product types use it, and where it usually sits on a label across everything we have researched.
- This is cosmetic information, not medical advice, and nothing here diagnoses or treats a health condition.
- Formula readings: derivation v23. Record last updated 2026-10-08.
