Cosmetic Stores · Formulated and filled in the USA
The serum aisle never tells you what it weighs.
Every hair serum on the shelf says weightless. Northline prints a number instead — 0 to 5, on the bottle and on every page — for how much one application actually leaves on the strand. Then it tells you the number your hair can carry.
All prices in USD · Free US shipping over $45 · 45-day returns
The scale
Zero to five, and what each one means
Weightless
Weight 0
Rinses out, or dries down to nothing you can feel. Shampoos, conditioners and water-light mists sit here — nothing in this band can weigh hair down, whatever your hair is like.
Light
Weight 1–2
A pea-sized amount disappears into most hair. This is the band fine and thin hair should live in, and the only band we would put anywhere near the root.
Medium
Weight 3–4
You will feel this one on the strand. Mid-lengths and ends only, on medium to thick hair — or on fine hair as a wash-day treatment and nothing more.
Rich
Weight 5
Heavy by design, for coarse, curly and colour-worn hair that drinks it. On anything finer it will look greasy within a day — that is not the product failing, it is the wrong number for the hair.
The useful half
A 4 is heavy on fine hair and light on curls
The number on the bottle only means something measured against your own hair. So every product page states its weight, and this is the ceiling to hold it against. It is deliberately conservative: the failure mode of a hair serum is looking greasy by lunchtime, and the shop that told you to use less is the one you come back to.
Find your ceilingFine / thin
up to 2
Strands you can barely feel between two fingers, and volume that has dropped by the evening. Stay at 2 or under, keep everything off the root, and use half of what the bottle suggests before you use all of it.
Medium
up to 3
The default. 3 is comfortable on wash day and 1–2 on the days between. Mid-lengths down.
Thick / coarse
up to 4
Carries weight well and usually wants more than the label suggests. Work up to 4 before you reach for 5.
Curly / coily
up to 5
The one hair type the top of the scale is built for. Apply to soaking-wet hair, in sections, and do not rake it through once it has dried.
Start here
Three that suit most hair
Weightless Smoothing Serum
The one fine hair can actually wear
$28.00
Bond Repair Serum
For hair that has been bleached, coloured or over-heated
$36.00
Heat Shield Spray
Rated to 450°F, and light enough to use every day
$26.00
The Fine Hair Week
Everything at weight 1 or under. Nothing that can flatten you
$84.00
What is on every page
Printed, not implied
The full ingredient list
Every product page carries the complete INCI list in descending order, not a highlight reel of the four ingredients with the best names.
The strength of the ingredient
Where a percentage matters — salicylic acid, UV filter, protein — it is stated as a number rather than as a claim about being clinical.
A cautions block
Who a product is not for, what it does to fine or colour-treated hair, and what not to layer it with. The most useful block on the page, and the one most brands leave out.
Fill size and net weight
In millilitres and grams, on every product, so a price per bottle can be compared to a price per bottle.
And what we will not say
Northline sells cosmetics. Nothing here regrows hair, treats hair loss or fixes a scalp condition — those are drug claims, and a shop that makes them casually is telling you something about the rest of its copy. Our products change how hair looks, feels and behaves. That is the whole claim, and it is the reason the numbers can be honest.
There are also no star ratings, no review counts and no testimonials anywhere on this site. Not because we do not want them — because this shop is new, and numbers we cannot yet stand behind are worth less than saying so.
The centre of the catalog
Serums, weight 1 to 5
Weight 1 to 5. The centre of the catalog. One job each, at a stated strength, with a number on the bottle that tells you what it will do to your hair before you open it.
Whole wash days
Three routines, costed
Each one states the highest weight it contains and the order to use it in, and each is priced below the sum of its parts. Neither a subscription nor an enrolment — you buy the box once.
The Fine Hair Week
$84.00tops out at 1
Everything at weight 1 or under. Nothing that can flatten you
- 1 × Daily Wash0
- 1 × Daily Conditioner0
- 1 × Weightless Smoothing Serum1
- 1 × Heat Shield Spray1
The Repair Week
$86.00tops out at 2
The bond complex in all three steps it belongs in
- 1 × Bond Repair Wash0
- 1 × Bond Repair Mask2
- 1 × Bond Repair Serum1
The Curl Week
$92.00tops out at 4
The top of the weight scale, used the way it is meant to be
- 1 × Daily Wash0
- 1 × Deep Moisture Mask4
- 1 × Leave-In Milk2
- 1 × Frizz Control Serum4
Terms of sale
Currency
All prices are shown and charged in US Dollars (USD). Sales tax, where it applies, is calculated and shown at checkout before you pay.
Shipping
$4.95 standard, free over $45. 3–5 business days after dispatch, with tracking on every order. United States only.
Returns
45 days on anything unopened. An opened product that caused a reaction is replaced or refunded — send a photograph and keep the product.
On your statement
Charges appear as NORTHLINE. If a line looks unfamiliar, contact us before your bank — we can resolve it the same day.