Penetraitt Serum
Finisher / Serum, lightweight
- Finisher
- serum
- Sulfate-free
- Protein-free
- Curly-method
- Not cruelty-free · PETA-listed
Scent:
The ingredient list declares fragrance. What it smells of is not stated, and we do not guess.
Personal fit
Is this right for you?
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- In 10 minutes we can identify your exact hair condition and traits.
- Every product matched against your hair across the 22 factors we check.
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- Your goals, scalp, damage history, water, budget, and scent preferences all shape your plan.
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Show all 22 factors we check
The rest of what your plan weighs on this product.
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Your avoid-list
Upper-mid price for a serum
$9.59/oz at 3.2 oz — more than 53% of the 77 serums , which mostly run $3.25–14.50/oz. The cost less.
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.
Water-first and light: unlikely to flatten fine hair.
No oils or butters in the list.
The silicones here are the water-soluble kind.
Fast-drying alcohol in the first three ingredients.
Fragrance sits in the first eight ingredients — a larger share of the formula.
Ingredients that matter
The ingredients that change a decision
The workhorse ingredients plus anything lower down that changes a decision. These 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 |
|---|---|---|---|
| Alcohol Denat. | drying alcohol | Speeds drying — and can read dry on the hair | Drying |
| Water | solvent | The base everything else is dissolved in | Neutral |
| Niacinamide | vitamin | A marketed vitamin addition | Detangles |
| Peg/Ppg-20/23 Dimethicone | emulsifier | Keeps oil and water mixed | Shine |
| Caffeine | active | The over-the-counter active | Active |
| FragranceParfum | fragrance | The scent | Fragrance |
| Acrylates/C10-30 Alkyl Acrylate Crosspolymer | thickener | Adjusts the texture | Holds |
| Sodium Hyaluronate | humectant | Adds a little water-binding | Moisturizes |
| Hexyl Cinnamal | fragrance | The scent | Fragrance |
| Benzyl Salicylate | fragrance | The scent | Fragrance |
| Linalool | fragrance | The scent | Fragrance |
| Citronellol | fragrance | The scent | Fragrance |
Full ingredient list (16)
US labelling rules put ingredients above 1% in descending order of amount; below 1% they may be listed in any order. Annotations keep three readings separate: the ingredient's general function, its role in this product type, and what its position can support.
-
1
Alcohol Denat.
General function
Fast-drying alcohol used to make sprays set quickly. In leave-on products it can leave hair feeling dry, especially in high position on the list.
Leading ingredientListed in the first three ingredients, it is likely a structural part of this formula.
PubChemMay suitFine or easily flattened hairEvaporates on contact, which is how a spray sets almost instantly and leaves no weight behind it.
May not suitDry, coarse, or high-porosity hairPorous hair gives water up easily as it is; a fast-evaporating solvent high on the list accelerates that.
May not suitVery dry or highly damaged hairIt evaporates quickly and takes some water with it. On hair already short of moisture, a formula built on a lot of it can finish drier than it started.
- drying alcohol
- solvent
-
2
Water
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
Niacinamide
General function
Vitamin B3, used in scalp products for conditioning claims.
Leading ingredientListed in the first three ingredients, it is likely a structural part of this formula.
PubChemMay suitFrizz-prone, damaged, or high-friction hairDeposits a lubricating layer that makes combing easier, which is most of what stops mechanical damage adding to frizz.
- vitamin
- conditioning agent
-
4
Peg/Ppg-20/23 Dimethicone
General function
An ethoxylated or propoxylated formulation aid. Ingredients of this family keep oils, silicones and fragrance evenly dispersed in a water-based product.
Supporting ingredientListed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.
- emulsifier
- silicone
- water-soluble silicone
-
5
Caffeine
General function
Included in scalp and thickening products for label appeal. Evidence for applied caffeine changing hair growth is limited.
Supporting ingredientPubChemListed in positions 4–8, it likely makes a meaningful contribution alongside the formula's main ingredients.
- active
- ▾Below about this point, order stops being meaningful — these are typically used at 1% or less.
-
6
Fragrance
· Parfum
General function
An undisclosed blend of scent ingredients. Regulations let it stay unlisted, so a fragrance-free product is the only way to be certain what is not in it.
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 not suitFragrance-sensitive routinesDeclared fragrance. On a fragrance-sensitive routine this is the line that decides it, wherever it sits on the label.
- fragrance
- declared fragrance
-
7
Acrylates/C10-30 Alkyl Acrylate Crosspolymer
General function
A gel-forming thickener that also keeps oils suspended. It contributes a little hold.
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 suitClimate-sensitive or frizz-prone hairA set polymer film is a physical barrier to humidity, so a style keeps its shape longer in damp conditions.
May suitMaximum-hold stylingSynthetic film formers dry into a continuous film, which is what holds a shape against movement and against humid air.
DependsBuild-up-sensitive routinesSome acrylate copolymers rinse with water and some need a detergent; the label alone does not say which one a formula used.
- thickener
- polymer
- film former
-
8
Sodium Hyaluronate
General function
A large water-binding molecule that sits on the surface holding moisture.
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 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
-
9
Glycerin
General function
A small water-loving molecule that draws moisture into the hair and holds it there. It is the most common softening ingredient in conditioners and leave-ins.
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
Hexyl Cinnamal
General function
A jasmine-like fragrance component named separately as a recognised allergen.
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 routinesOne of the 26 scent components the EU requires to be named individually above a threshold. It is named because it is a known contact allergen, not because it is unusual.
- fragrance
- named fragrance allergen
-
11
Benzyl Salicylate
General function
A soft floral fragrance component listed separately as a recognised allergen.
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 routinesOne of the 26 scent components the EU requires to be named individually above a threshold. It is named because it is a known contact allergen, not because it is unusual.
- fragrance
- named fragrance allergen
-
12
Linalool
General function
A floral fragrance component listed separately as a recognised contact allergen.
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 routinesOne of the 26 scent components the EU requires to be named individually above a threshold. It is named because it is a known contact allergen, not because it is unusual.
- fragrance
- named fragrance allergen
-
13
Trideceth-6
- emulsifier
- solubilizer
-
14
Citronellol
General function
A rose-like fragrance component named separately as a recognised allergen.
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 routinesOne of the 26 scent components the EU requires to be named individually above a threshold. It is named because it is a known contact allergen, not because it is unusual.
- fragrance
- named fragrance allergen
-
15
Geraniol
General function
A rose-scented fragrance component, listed on its own because some people react to it.
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 not suitFragrance-sensitive routinesOne of the 26 scent components the EU requires to be named individually above a threshold. It is named because it is a known contact allergen, not because it is unusual.
- fragrance
- named fragrance allergen
-
16
Limonene
General function
A citrus-smelling fragrance component that EU rules require to be named separately because some people react to it.
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 routinesOne of the 26 scent components the EU requires to be named individually above a threshold. It is named because it is a known contact allergen, not because it is unusual.
- fragrance
- named fragrance allergen
What the whole list adds up to
- 7 fragrances
- 6 named fragrance allergens
- 2 solvents
- 2 emulsifiers
- 2 humectants
- 1 drying alcohol
- 1 vitamin
- 1 conditioning agent
- 1 silicone
- 1 water-soluble silicone
- 1 active
- 1 declared fragrance
- 1 thickener
- 1 polymer
Ingredient list captured 2026-08-27. Formulas change — check the package in your hand when an ingredient matters to you.
Price · 3.2 oz
Priced above the products that do the same job. Stores sell it above the $13 line; products that do this job typically go for about $31 at this size.
Sizes
The 3.2 oz costs the least per ounce — 29% less than the 3.4 oz.
Show the price ladder
Where we’ve seen it2 listings · 2 stores
3.2 ozmost listedBest per ounce
-
ShopSimon
$30.693.2 oz · $9.59/ozSep 5Lowest per ozSale · was $42.00
3.4 oz
-
Ulta
$46.003.4 oz · $13.53/ozAug 28Lowest per oz
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
- 3.2 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.
- Seen at $30.69 is the price we have observed for the 3.2 oz. We need three stores before we call a price commonly seen.
- Good value under $13 comes from the 6 products we score as doing the same job as this one. A quarter of them cost less than $4.15/oz; at 3.2 oz that is $13. Under that line you are paying less than most of them.
- Each size is guarded on its own, so a multipack or a marketplace listing at one size cannot move another.
- About $31 is what those same products typically cost at this size — the midpoint of their prices per ounce, scaled to 3.2 oz.
Formula
Nothing separates this from the middle of the range for serums, on formula or on cost per ounce.
How the score is counted
- 1 products that do the same job cost less per ounce
- Costs more per ounce than 53% of the 77 serums we’ve priced
- No oils or butters in the working zone in the formula
- Prestige tier, sold at Ulta and Salons
- A shine systemThe silicone, oil, or ester that produces gloss.3 pts
- A weightless carrierDelivers the shine without leaving grease.2 pts
- Oils or butters in the working zoneSoftens the strand rather than just coating it.2 pts
- An antioxidantKeeps the oils in the bottle from going off.1 pt
- No drying alcohol in the first threeFast drying without leading on alcohol.1 pt
- Fragrance kept out of the top eightScent as a finishing touch, not a major share.1 pt
The formula score is completeness for the job: the share of the systems this product type is normally built around that we can find in this list, weighted. It is not efficacy, not quality, and it never compares across product types.
Does the same job, for less
Same derived functions — what it cleans, conditions, coats or holds — at a lower cost per ounce. Scent, texture and where you buy it can still differ.
- Heat protect
- Protein-free
- Lightweight
- Function
- Also
See more alternatives in the product library
These are functional neighbours, not personal recommendations — they are close on formula, not chosen for anyone. Get the one that fits your hair, routine, and budget
Final decision
Should you buy it?
Only for a specific needHair that stiffens on protein — for a protein-free formula and something that will not weigh hair down
Worth skipping for anyone sensitive to fragrance, very dry or high-damage hair, or anyone who will not scrunch out a cast
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 Sebastian
How this page was made
- Everything above is generated from our researched product record — identity, the ingredient list as printed, the brand's own claims, dated price observations, and review themes written in our researchers' own words. No part of this page is written per 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.
- 2 sources consulted for this product (0 manufacturer or regulatory, 1 retailer, 1 editorial), last checked 2026-09-05.
- Ingredient references are linked for 8 of 12 product-aware annotations on this page. Fit notes are conditional formulation guidance, not a conclusion about the finished product or about you.
- We have not tested this product in a lab and we do not physically test your hair. Formula readings come from the ingredient list; behaviour claims are labelled as the brand's.
- Ingredient order tells you relative amount only above roughly 1%. Prices are observations on the dates shown and change without notice.
- 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 v22. Record last updated 2026-09-09.