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Side by side

Nioxin System 1 Leave In Treatment vs Nioxin System 4 Leave In Treatment

68% function match · 5 of the 10 functions we compared match Formula overlap 65%. Nioxin System 1 Leave In Treatment and Nioxin System 4 Leave In Treatment share 4 ingredients among each other's most prominent.

Based on your consultation

Which of these fits your hair?

We check your pattern, moisture need, scalp, fragrance tolerance, weight sensitivity and more against each formula — and say which one lines up.

Your profile at a glance

  • Your answers appear here
  • Your answers appear here
  • Your answers appear here
  • Your answers appear here

When each one is the right call

What each formula is built for, from its own ingredient list.

  • System 1 Leave In Treatment — fine hair
  • System 4 Leave In Treatment — fine hair

Side by side

Every trait, aligned

One row per trait, read from each product’s own ingredient list and record. A dash means we have not researched that field for that product — it is not a “no”.

Trait
Nioxin System 1 Leave In Treatment — front of package Nioxin

System 1 Leave In Treatment

  • Scalp treatment
  • Salon
  • Sulfate-free
  • Silicone-free
Nioxin System 4 Leave In Treatment — front of package Nioxin

System 4 Leave In Treatment

  • Scalp treatment
  • Salon
  • Sulfate-free
  • Curly-method
Price, size & price per ounce
$27 3.38 oz · $10.28/oz
$27 3.38 oz · $7.99/oz
Value / price positioning
Upper-mid price for a scalp treatment $$$$$ Salon tier · costs more than 58% of the 154 scalp treatments we’ve priced
Upper-mid price for a scalp treatment $$$$$ Salon tier · costs more than 53% of the 154 scalp treatments we’ve priced
Best for hair types
All types Nothing in the formula or the claims narrows this to one pattern. Your hair
All types Nothing in the formula or the claims narrows this to one pattern. Your hair
Moisture level Differs
Moderate Humectants in the working part of the formula. Your hair
Low Humectants appear, but low enough to be a minor part. Your hair
Slip / detangling Differs
Little Nothing here is built to reduce combing force. Your hair
Some Some slip, mostly from esters or silicones rather than conditioners. Your hair
Weight on hair Same
Light Water-first and light: unlikely to flatten fine hair. Your hair
Light Water-first and light: unlikely to flatten fine hair. Your hair
Fragrance
Present Fragrance is listed; it sits below the working ingredients. Your hair
Present Fragrance is listed; it sits below the working ingredients. Your hair
Protein Same
Minor Protein appears, low enough to be a supporting ingredient. Your hair
Minor Protein appears, low enough to be a supporting ingredient. Your hair
Silicone / wax buildup Differs
None Nothing here needs a detergent wash to remove. Your hair
Low The silicones here are the water-soluble kind. Your hair
Clarifying wash needed
Moderate Your hair
Moderate Your hair
Oils and butters Same
None No oils or butters in the list. Your hair
None No oils or butters in the list. Your hair
Hard-water defence Same
Chelators present Chelators are present — they bind hard-water and pool minerals. Your hair
Chelators present Chelators are present — they bind hard-water and pool minerals. Your hair
Formula completeness
out of 10
A simple formula
out of 10
A simple formula
Who should choose this
  • Fine hairthat flattens under most products
  • Silicone-free routinesno silicones appear in the list
  • Very dry hairno fast-drying alcohol in the list
  • Easy to findsold through several channels
  • Fine hairthat flattens under most products
  • Very dry hairno fast-drying alcohol in the list
  • Sun and colour fadea UV filter is in the list
  • Easy to findsold through several channels
Why you might skip it
  • Scents bother youthis product carries a scent
  • Vegan and cruelty-freeour record does not support both claims here
  • Tight budgetsit sits in the upper price tiers
  • Scents bother youthis product carries a scent
  • Silicone-free routinesit does contain silicones — the water-soluble kind
  • Vegan and cruelty-freeour record does not support both claims here
from the formula stated by the brand reported by reviewers Scale: 1 dot low · 5 dots high, within this product type.
More facts about each one
Type
Scalp treatment
Scalp treatment
Where to buy
Salons · Specialty beauty · Amazon
Salons · Specialty beauty · Amazon
Free of
  • sulfate-free
  • silicone-free
  • curly-method compatible
  • sulfate-free
  • curly-method compatible
Cruelty-free
Not cruelty-free · PETA-listed
Not cruelty-free · PETA-listed
Scent
Scented, not described
Scented, not described
How often
every wash
every wash

Facts as we recorded them. A dash means we have not researched that field for that product — it is not a "no".

The bottom line

The bottom line depends on your hair

Which of these two suits you is a question about your hair, not about them. The consultation answers it — and tells you what your routine needs around it.

Take the consultation

$49.00 once, for your consultation and hair profile. No subscription, no required purchases.

The detail behind the table

Where the readings above come from: the ingredient lists themselves, each brand’s claims checked against them, what owners report, and cost per ounce in context.

Shared and distinct ingredients

Shared and distinct ingredients

Computed from the ingredient lists as printed. "Shared" means both lists carry it; where it sits on each label is stated, because position is what tells you how much.

What both formulas carry

IngredientSystem 1 Leave In TreatmentSystem 4 Leave In Treatment
Water
Neutral
#1Leading
#1Leading
Niacinamide
Detangles
#2Leading
#2Leading
Caffeine
Active
#3Leading
#4Supporting
Phenoxyethanol
Stabilizes
#4Below the 1% line
#7Below the 1% line
Sodium Benzoate
Stabilizes
#5Below the 1% line
#8Below the 1% line
Benzyl Alcohol
Stabilizes
#6Below the 1% line
#10Below the 1% line
Polysorbate 80
Stabilizes
#8Below the 1% line
#19Below the 1% line
Fragrance
Fragrance
#16Below the 1% line
#18Below the 1% line
Mentha Arvensis Leaf Oil
Fragrance
#17Below the 1% line
#17Below the 1% line
Mentha Piperita (Peppermint) Oil
Fragrance
#18Below the 1% line
#22Below the 1% line
Limonene
Fragrance
#21Below the 1% line
#23Below the 1% line

What only one of them carries

System 1 Leave In Treatment

System 4 Leave In Treatment

Full ingredient list — System 1 Leave In Treatment (43)
Full ingredient list — System 4 Leave In Treatment (44)

Claims check

What each brand says, against what each formula shows

Claims are quoted from each brand. We only mark one supported, partly supported, or conflicting when that product’s ingredient list actually speaks to it.

VerdictsSystem 1 Leave In TreatmentSystem 4 Leave In Treatment
Supported
1
1
Partly supported
1
1
Stated by brand
0
0
Potential conflict
0
0
Thickens the hair
SupportedLeaves room for lift.
SupportedLeaves room for lift.
Nourishes the scalp
Partly supportedSome hydration, at a low level.
Partly supportedSome hydration, at a low level.

System 1 Leave In Treatment

No claims recorded for this product beyond the ones above.

System 4 Leave In Treatment

No claims recorded for this product beyond the ones above.

Price check

Cost per ounce, in context

Cost per ounce against every product of this type we have priced, each at the size it is most often sold in. Value labels are computed from that percentile and from how many products that do the same job cost less; they are comparisons, not judgements about a brand.

$7.99/oz vs $10.28/oz — Nioxin System 1 Leave In Treatment costs about 1.3× more per ounce than Nioxin System 4 Leave In Treatment.

$1.25/oz median $7.19/oz $55.03/oz $10.28/oz System 1 Leave In Treatmen $7.99/oz System 4 Leave In Treatmen

Every mark sits on one distribution because these are compared against the same set: 154 scalp treatments with a computable unit price.

Value readSystem 1 Leave In TreatmentSystem 4 Leave In Treatment
Label
Upper-mid price for a scalp treatmentSits in the middle of the range for scalp treatments per ounce.
Upper-mid price for a scalp treatmentSits in the middle of the range for scalp treatments per ounce.

Computed from cost per ounce against every product of this type we have priced, and from how many products that do the same job cost less. It is a comparison, not a judgement about the brand.

Compare with something else

Close formulas to each of these, as their own comparison pages.

System 1 Leave In Treatment · System 4 Leave In Treatment · All scalp treatments in the library

How this page was made

  • This page is assembled from the same researched records the individual product pages render: identity, each ingredient list as printed, each brand's own claims, dated price observations, and review themes written in our researchers' own words. Nothing on it is written per comparison.
  • We do not rank these against each other. Which of them suits you depends on your hair, and that is what the consultation works out.
  • The formula similarity percentage is a stored, precomputed number: position-weighted overlap of the two ingredient lists blended with agreement on the attributes we derive. It measures how alike two formulas are, not how well either works.
  • 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.
  • 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.
  • 12 sources were consulted across the products on this page.
  • Ingredient order tells you relative amount only above roughly 1%. Prices are observations on the dates shown and change without notice. We do not sell these products and take no placement fees.
  • This is cosmetic information, not medical advice, and nothing here diagnoses or treats a health condition.

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