Cosnori Serum Eyelash Agent
COSNORI eyelash serums are leave-on lash conditioners formulated to nourish lashes at the root and along the shaft. This collection brings together the brand's eyelash-care line: a concentrated 100 EX nourishing serum, the Long Active formula for daily conditioning, and a Black Tinting serum that adds depth while it cares. Each one applies like a thin brush-on liquid you sweep along the lash line as the last step of an evening routine.
By Skinsli editorial Updated
Buying guide
COSNORI Eyelash Serum Buying Guide
COSNORI builds its eyelash range around brush-on nourishing serums you leave on overnight. The three formulas in this collection cover slightly different goals, from a concentrated nourishing agent to a tinting serum that darkens lashes as it conditions. This guide explains what each one does, how to apply them, and how to pick the formula that fits your lashes.
What a COSNORI eyelash serum actually is
These are leave-on conditioning serums, not mascaras and not lash extensions. You apply a thin film along the upper lash line and let it sit, so the formula stays in contact with the lash roots and shafts for hours. COSNORI calls each one an eyelash nourishing agent, which signals the intent: keep lashes conditioned and less prone to breakage with daily use rather than colour them for a single day.
Because they are leave-on products, consistency matters more than any single application. The brand's range is sized small, between 7g and 9g per tube, which is normal for a product you dose one brush stroke at a time.
The three formulas in this grid
This collection currently lists three COSNORI serums. The Eyelash Serum 100 EX (7g) is the concentrated nourishing agent in the line. The Long Active Eyelash Serum (9g) is the everyday conditioning option in a larger tube. The Black Tinting Serum (9g) adds a dark tint while it conditions, so lashes read deeper between mascara wears.
If you are deciding between them, the split is mostly nourishing versus nourishing-plus-tint, with the 100 EX sitting at the more concentrated end.
Tinting serum versus a clear nourishing serum
The Black Tinting Serum does two jobs at once. It carries the same leave-on conditioning idea as the clear serums, but it also deposits a dark tone so bare lashes look fuller without mascara. The trade-off is that a tinting formula is less suited to people who want a fully colourless product, for example anyone who reacts to lash dyes or prefers to keep tinting to a salon.
The 100 EX and Long Active formulas stay clear, so they fit under makeup and work for anyone who only wants the conditioning step.
How to apply a lash serum
Start with a clean, dry lash line. Remove all eye makeup first, because residue and oils sit between the serum and the lashes. Sweep a small amount along the upper lash line the way you would draw a thin eyeliner, then let it dry before you lie down.
One pass is enough. Loading more product on does not speed up conditioning and only raises the chance of it migrating into the eye. Let the serum settle for a minute or two before any other overnight step.
Where it fits in your routine
Treat a COSNORI eyelash serum as a night step. Cleanse, do your usual skincare around the eyes, and apply the serum last so nothing layers on top of it. Keep it off the waterline and away from the inner corner.
The tinting serum is the one exception worth planning around. Apply it on a night when you are not also using a strong eye-area exfoliant, so the freshly tinted lashes are not disturbed.
What to expect and how long it takes
A conditioning serum works gradually. Lashes grow and shed on their own cycle, so give a clear nourishing formula several weeks of nightly use before you judge it. The tinting serum shows its effect immediately because the result is visible tone rather than long-term conditioning.
If your lashes feel dry or brittle, the conditioning step is the part doing the work, and that is the part that needs patience and a steady routine.
Sizing and value
The tubes run small by design: 7g for the 100 EX and 9g for the Long Active and Black Tinting serums. Since you use roughly one brush stroke per eye per night, a tube lasts a long time relative to its size. Buy the 9g formats if you apply nightly and want fewer repurchases; the 7g 100 EX makes sense if you want the more concentrated nourishing agent and dose it less often.
Authenticity and Korean sourcing
COSNORI is a Korean brand, and these eyelash serums ship as the Korean-market formulas. Eye-area products are worth buying from a source you trust, since you are applying them close to the eye every night. We carry the COSNORI line directly so the formula and packaging match what the brand sells in Korea.
FAQ
Frequently asked questions
FAQ
Frequently asked questions
What is the difference between the COSNORI Eyelash Serum 100 EX and the Long Active Eyelash Serum?
The 100 EX is the concentrated nourishing agent in a 7g tube, while the Long Active is the everyday clear conditioning serum in a larger 9g tube. Both stay clear and apply along the lash line; pick the 100 EX if you want the more concentrated formula and the Long Active if you want a bigger size for nightly use.
What does the COSNORI Black Tinting Serum do?
It conditions lashes like the clear serums but also deposits a dark tone, so bare lashes look deeper and fuller without mascara. It is the only formula in this collection that adds visible colour; the 100 EX and Long Active serums stay colourless.
How do I apply a COSNORI eyelash serum?
Start with clean, dry lashes free of makeup and oil. Sweep one thin pass along the upper lash line like a fine eyeliner, then let it dry before lying down. One application per eye is enough; more product does not condition faster and can migrate into the eye.
When in my routine should I use these serums?
Use them as the last step at night, after cleansing and your usual eye-area skincare, so nothing layers over the serum. Keep it off the waterline and inner corner. Apply the Black Tinting Serum on a night you are not also using a strong eye exfoliant so the fresh tint is not disturbed.
How long before a COSNORI lash serum makes a difference?
The clear nourishing serums work gradually with nightly use, so give them several weeks before judging since lashes grow and shed on their own cycle. The Black Tinting Serum is the exception: its darkening effect is visible right away because it deposits tone rather than conditioning over time.
How long does a 7g or 9g tube last?
Because you use about one brush stroke per eye each night, the small tubes last a long time. The 9g Long Active and Black Tinting formats suit nightly users who want fewer repurchases, while the 7g 100 EX is the more concentrated option you can dose less often.
Are these COSNORI eyelash serums authentic Korean products?
Yes. COSNORI is a Korean brand and these serums ship as the Korean-market formulas. We carry the line directly, so the formula and packaging match what the brand sells in Korea, which matters for a product you apply near the eye every night.