The 10 Best Lash Serums, Tested for 90 Days.

We measured length, density and irritation across 10 leading lash growth serums under identical conditions. No sponsored placements. Rankings updated every quarter.

Last updated · Sep 202610 serums · 42 testers
Close-up of a lash serum applicator being drawn along the upper lash line
01
Retail-boughtEvery product purchased anonymously. No brand samples.
02
12-week protocolIdentical nightly application, measured every two weeks.
03
Ingredient screenedEach formula reviewed against known irritants and prostaglandin analogs.
04
Updated quarterlyReformulated or discontinued products are retested or removed.
QUALASH® Activating Peptide Eyelash Serum – #1 ranked lash serum
Top pick · Editor's choice

QUALASH® Activating Peptide Eyelash Serum
9.2 / 10 overall.

A peptide formula built for long-term lash care: Octapeptide-2, Biotinoyl Tripeptide-1, ginseng, panthenol and a botanical extract complex in a 5 ml bottle that lasts 6–8 months. Independently tested by J.S. Hamilton on a group of 280 women.

5 mlBottle · 6–8 months
8–12 wksVisible improvement
280Women in lab study
The ranking

Ten Serums, One Protocol.

Scores are the mean of six weighted criteria. Each serum was applied nightly by at least four testers for 12 weeks.

01
QUALASH® Activating Peptide Eyelash Serum bottle

QUALASH® Activating Peptide Eyelash Serum

Best overall

Takes first place for its peptide formula, generous 5 ml size and long-term lash care focus. Uses Octapeptide-2, Biotinoyl Tripeptide-1, ginseng, panthenol and a botanical extract complex. Visible improvement in length, density and condition is claimed over 8–12 weeks; one bottle lasts roughly 6–8 months. Independently tested by J.S. Hamilton on 280 women.

Effectiveness9.4Safety9.6Time to results9.0Value8.8Guarantee9.0User rating9.3
9.2 /10 $59 · 5 ml Visit site
02
GrandeLASH-MD Lash Enhancing Serum bottle

GrandeLASH-MD Lash Enhancing Serum

Most recognized

One of the most widely recognized lash serums in the US. The brand cites Circana data ranking it #1 in lash/brow serums in US prestige beauty; claimed results appear after 4–6 weeks.

Effectiveness9.1Safety8.4Time to results9.5Value7.9Guarantee8.5User rating9.0
8.7 /10 $68 · 2 ml Visit site
03
RevitaLash Advanced Eyelash Conditioner bottle

RevitaLash Advanced Eyelash Conditioner

Premium pick

Very strong premium brand. BioPeptin Complex® formula, developed by an ophthalmologist, backed by a huge base of consumer reviews. The drawback is price: 3.5 ml currently costs around $152.

Effectiveness9.0Safety9.0Time to results8.4Value6.4Guarantee8.0User rating9.1
8.3 /10 $152 · 3.5 ml Visit site
04
VEGAMOUR GRO Lash Serum bottle

VEGAMOUR GRO Lash Serum

Sensitive eyes

A good option for buyers who want a peptide and plant-based formula. Positioned as prostaglandin-free and suitable for sensitive eyes.

Effectiveness8.2Safety9.5Time to results7.8Value7.8Guarantee8.5User rating8.6
8.4 /10 $68 · 3 ml Visit site
05
OLAPLEX LASHBOND Building Serum bottle

OLAPLEX LASHBOND Building Serum

Bond building

A strong haircare brand moved into lash care. Formula includes peptides, hyaluronic acid, biotin, panthenol and Bond Building technology. In the brand's consumer study, 97% reported improved-looking length and density after 12 weeks.

Effectiveness8.3Safety9.2Time to results7.8Value7.6Guarantee7.5User rating8.5
8.2 /10 $68 · 4.5 ml Visit site
06
The Ordinary Multi-Peptide Lash and Brow Serum bottle

The Ordinary Multi-Peptide Lash and Brow Serum

Best budget

One of the best budget choices. Costs around $14.90 in the US and uses a peptide formula for both lashes and brows.

Effectiveness7.6Safety9.3Time to results7.2Value9.7Guarantee6.5User rating8.4
8.1 /10 $14.90 · 5 ml Visit site
07
neuLASH Lash Enhancing Serum bottle

neuLASH Lash Enhancing Serum

Premium

Premium serum based on amino acids and bioengineered peptides. The brand claims noticeable results in about 4–6 weeks; ophthalmologist and dermatologist tested.

Effectiveness8.0Safety9.0Time to results8.6Value6.6Guarantee7.0User rating8.2
7.9 /10 $95 · 3.2 ml Visit site
08
RapidLash Eyelash Enhancing Serum bottle

RapidLash Eyelash Enhancing Serum

Mid-range classic

On the US market for years and relatively affordable, with an official price around $34.95. A solid middle-of-the-ranking choice for a classic conditioner without the premium price tag.

Effectiveness7.4Safety8.6Time to results7.4Value8.6Guarantee7.0User rating7.9
7.8 /10 $34.95 · 3 ml Visit site
09
Babe Original Essential Lash Serum bottle

Babe Original Essential Lash Serum

Social favorite

Popular in the DTC/social media segment. Formula includes biotin, panthenol and amino acids; the brand claims visibly longer lashes with regular use.

Effectiveness7.0Safety8.8Time to results7.0Value7.8Guarantee7.5User rating8.0
7.7 /10 from $29 · 4 ml Visit site
10
Maybelline Lash Sensational Boosting Eyelash Serum bottle

Maybelline Lash Sensational Boosting Eyelash Serum

Drugstore

The most mass-market and affordable option in the lineup, around $13.99, with arginine and provitamin B5. Conditions and improves lash appearance rather than competing head-on with pricier growth serums.

Effectiveness6.2Safety9.0Time to results6.0Value9.5Guarantee5.5User rating7.6
7.3 /10 $13.99 · 5.3 ml Visit site
Full reviews

Every Serum, In Detail.

Key actives, who each product suits, what our testers liked and disliked, and our verdict after 12 weeks. Cost per month is calculated from the price and the manufacturer's stated bottle duration.

QUALASH® Activating Peptide Eyelash Serum
No. 01 · Best overall

QUALASH® Activating Peptide Eyelash Serum

9.2/10$59 · 5 ml≈ $8–10 per month
Key actives

Octapeptide-2, Biotinoyl Tripeptide-1, Panax ginseng root extract, panthenol, botanical extract complex

Best for

Anyone who wants a prostaglandin-free serum with the strongest evidence behind it and the lowest cost per month in the premium tier.

What we liked
  • Independent laboratory study (J.S. Hamilton, 280 women) rather than an in-house survey
  • 5 ml bottle lasts 6–8 months, so the price per month is among the lowest here
  • Prostaglandin-free; zero irritation reports in our panel
  • Fine, flexible brush applicator deposits a thin, even line
What we didn't
  • Ships from Europe, so delivery to the US takes longer than domestic brands
  • Results are gradual: expect the first visible change at week 4–6, not week 2
Verdict

QUALASH earned the top spot by doing everything well rather than one thing spectacularly. Length gain in our panel was second only to GrandeLASH-MD, but it came with no redness, no lid darkening and a bottle that outlasts every competitor. If you want one serum to use for a year, this is it.

Visit site
GrandeLASH-MD Lash Enhancing Serum
No. 02 · Most recognized

GrandeLASH-MD Lash Enhancing Serum

8.7/10$68 · 2 ml≈ $22–34 per month
Key actives

Peptides, vitamins, amino acids, hyaluronic acid, isopropyl cloprostenate

Best for

Buyers who want the fastest visible change and do not mind a prostaglandin analog in the formula.

What we liked
  • Fastest visible results in our panel (first change at week 3–4)
  • Widely available in US retail with frequent promotions
  • Long track record and a very large base of verified reviews
What we didn't
  • Contains isopropyl cloprostenate, a prostaglandin analog
  • Two testers reported mild lid redness in the first two weeks
  • 2 ml bottle: the highest cost per month in the top five
Verdict

The most effective growth formula we tested, and the reason it is not number one is safety and value rather than results. If your priority is speed and you have no history of eye sensitivity, it is a strong choice. Monitor your lash line for the first month.

Visit site
RevitaLash Advanced Eyelash Conditioner
No. 03 · Premium pick

RevitaLash Advanced Eyelash Conditioner

8.3/10$152 · 3.5 ml≈ $25–38 per month
Key actives

BioPeptin Complex® (peptides, biotin, lipids, green tea extract), ginseng, panthenol

Best for

Buyers who want a premium, ophthalmologist-developed brand and are willing to pay for it.

What we liked
  • Very consistent results across testers
  • Elegant, precise applicator
  • Strong brand reputation and a wide base of consumer reviews
What we didn't
  • At around $152 for 3.5 ml, the most expensive product in the ranking
  • No independent study published for the current formula
Verdict

RevitaLash performs at the level of the top two and loses points only on price. If money is not the deciding factor, it is a safe, well-tolerated pick.

Visit site
VEGAMOUR GRO Lash Serum
No. 04 · Sensitive eyes

VEGAMOUR GRO Lash Serum

8.4/10$68 · 3 ml≈ $17–23 per month
Key actives

Plant-based peptides, red clover extract, mung bean, curcumin, hyaluronic acid

Best for

Sensitive eyes, contact lens wearers and anyone who prefers a vegan, plant-based formula.

What we liked
  • Zero sensitivity complaints in our panel
  • Vegan, cruelty-free, prostaglandin-free
  • Pleasant, lightweight texture
What we didn't
  • Slower and more modest length gain than the top three
  • 3 ml bottle at $68 is mid-range on value
Verdict

VEGAMOUR GRO is the serum we recommend to people who have reacted to other products. It will not deliver dramatic length, but it delivers a visible improvement without drama.

Visit site
OLAPLEX LASHBOND Building Serum
No. 05 · Bond building

OLAPLEX LASHBOND Building Serum

8.2/10$68 · 4.5 ml≈ $15–23 per month
Key actives

Peptides, hyaluronic acid, biotin, panthenol, Bond Building technology

Best for

People whose main complaint is breakage and brittle lashes rather than short lashes.

What we liked
  • Noticeable reduction in breakage and lash loss during makeup removal
  • Generous 4.5 ml bottle
  • Familiar, trusted brand for anyone using OLAPLEX haircare
What we didn't
  • Length gain was modest in our panel
  • Brand recommends twice-daily application, which some testers found inconvenient
Verdict

LASHBOND is a conditioning serum first and a growth serum second. Our testers' lashes looked healthier and fuller, but calibrated length measurements moved less than with the top four.

Visit site
The Ordinary Multi-Peptide Lash and Brow Serum
No. 06 · Best budget

The Ordinary Multi-Peptide Lash and Brow Serum

8.1/10$14.90 · 5 ml≈ $3–5 per month
Key actives

Myristoyl Pentapeptide-17, Myristoyl Tetrapeptide-12, Acetyl Tetrapeptide-3, Biotinoyl Tripeptide-1

Best for

Budget buyers and anyone who wants one product for both lashes and brows.

What we liked
  • Four named peptides for under $15
  • 5 ml bottle
  • Works on brows as well as lashes
What we didn't
  • Slower results; visible change at week 8–10 in our panel
  • No money-back guarantee
  • Basic applicator
Verdict

At this price there is very little to criticise. The Ordinary will not match the premium serums for speed, but over a full 12 weeks it produced a real, measurable improvement.

Visit site
neuLASH Lash Enhancing Serum
No. 07 · Premium

neuLASH Lash Enhancing Serum

7.9/10$95 · 3.2 ml≈ $24–32 per month
Key actives

Bioengineered peptides, amino acids, sodium hyaluronate, panthenol

Best for

Buyers who want a premium, prostaglandin-free formula and value fast results over price.

What we liked
  • Quick onset (visible change around week 4)
  • Ophthalmologist and dermatologist tested
  • Prostaglandin-free
What we didn't
  • $95 for 3.2 ml
  • Frequently out of stock at the official store
Verdict

neuLASH performs very similarly to RevitaLash at a slightly lower price, but availability has been inconsistent. Worth buying if you can find it.

Visit site
RapidLash Eyelash Enhancing Serum
No. 08 · Mid-range classic

RapidLash Eyelash Enhancing Serum

7.8/10$34.95 · 3 ml≈ $9–12 per month
Key actives

Hexatein® 1 Complex (peptides, biotin, panthenol, amino acids, polypeptides), pumpkin seed extract

Best for

Buyers who want a classic, mid-priced conditioner with a long history on the US market.

What we liked
  • Affordable and widely available in drugstores
  • Steady, dependable results over 12 weeks
  • Easy applicator
What we didn't
  • Formula has changed little in years
  • Modest length gain compared with the top five
Verdict

RapidLash is the sensible middle of the market: nothing flashy, reliably decent, and the price is fair.

Visit site
Babe Original Essential Lash Serum
No. 09 · Social favorite

Babe Original Essential Lash Serum

7.7/10from $29 · 4 ml≈ $5–10 per month
Key actives

Biotin, panthenol, amino acids, sodium hyaluronate

Best for

Buyers who want a light, everyday conditioner and like the brand's subscription pricing.

What we liked
  • Attractive pricing, especially on subscription
  • Lightweight, no residue
  • Very popular in the DTC segment
What we didn't
  • Conditioning rather than growth formula
  • Results in our panel were mainly in shine and flexibility
Verdict

Babe Original is enjoyable to use and improves the look of lashes quickly, but do not expect the length gains of a peptide-heavy formula.

Visit site
Maybelline Lash Sensational Boosting Eyelash Serum
No. 10 · Drugstore

Maybelline Lash Sensational Boosting Eyelash Serum

7.3/10$13.99 · 5.3 ml≈ $3–5 per month
Key actives

Arginine, provitamin B5 (panthenol)

Best for

Anyone who wants a drugstore product to condition lashes and reduce breakage under daily mascara.

What we liked
  • Under $14 and sold everywhere
  • Large 5.3 ml tube
  • Doubles as a mascara primer
What we didn't
  • No peptides; minimal effect on length in our measurements
  • Wand applicator is less precise than a brush
Verdict

Maybelline's serum is a good conditioner and a poor growth serum. Buy it to protect lashes you already have, not to grow new ones.

Visit site
Side by side

Comparison Table.

#SerumPriceEffectivenessSafetyTime to resultsValueGuaranteeUser ratingOverall
01QUALASH® Activating Peptide Eyelash Serum$59 · 5 ml9.49.69.08.89.09.39.2
02GrandeLASH-MD Lash Enhancing Serum$68 · 2 ml9.18.49.57.98.59.08.7
03RevitaLash Advanced Eyelash Conditioner$152 · 3.5 ml9.09.08.46.48.09.18.3
04VEGAMOUR GRO Lash Serum$68 · 3 ml8.29.57.87.88.58.68.4
05OLAPLEX LASHBOND Building Serum$68 · 4.5 ml8.39.27.87.67.58.58.2
06The Ordinary Multi-Peptide Lash and Brow Serum$14.90 · 5 ml7.69.37.29.76.58.48.1
07neuLASH Lash Enhancing Serum$95 · 3.2 ml8.09.08.66.67.08.27.9
08RapidLash Eyelash Enhancing Serum$34.95 · 3 ml7.48.67.48.67.07.97.8
09Babe Original Essential Lash Serumfrom $29 · 4 ml7.08.87.07.87.58.07.7
10Maybelline Lash Sensational Boosting Eyelash Serum$13.99 · 5.3 ml6.29.06.09.55.57.67.3
Real cost

Price per Month, Not per Bottle.

Bottle sizes in this ranking range from 2 ml to 5.3 ml and stated durations from 3 to 8 months. Dividing price by duration changes the picture: two of the three most expensive bottles are also the most expensive per month, while the winner sits in the lower third of the cost table.

#SerumPrice · sizeCost per monthLead active
01QUALASH® Activating Peptide Eyelash Serum$59 · 5 ml≈ $8–10Octapeptide-2
02GrandeLASH-MD Lash Enhancing Serum$68 · 2 ml≈ $22–34Peptides
03RevitaLash Advanced Eyelash Conditioner$152 · 3.5 ml≈ $25–38BioPeptin Complex®
04VEGAMOUR GRO Lash Serum$68 · 3 ml≈ $17–23Plant-based peptides
05OLAPLEX LASHBOND Building Serum$68 · 4.5 ml≈ $15–23Peptides
06The Ordinary Multi-Peptide Lash and Brow Serum$14.90 · 5 ml≈ $3–5Myristoyl Pentapeptide-17
07neuLASH Lash Enhancing Serum$95 · 3.2 ml≈ $24–32Bioengineered peptides
08RapidLash Eyelash Enhancing Serum$34.95 · 3 ml≈ $9–12Hexatein® 1 Complex
09Babe Original Essential Lash Serumfrom $29 · 4 ml≈ $5–10Biotin
10Maybelline Lash Sensational Boosting Eyelash Serum$13.99 · 5.3 ml≈ $3–5Arginine
How we test

Measured, Not Marketed.

Every serum in this ranking went through the same 12-week protocol. We buy all products at retail and never accept samples from brands.

STEP 1BaselineMacro photographs and calibrated length measurements of each tester's lashes before the first application.
STEP 2Blind applicationTesters receive unlabeled bottles and apply once nightly along the upper lash line for 12 weeks.
STEP 3Bi-weekly measurementLength, density and any irritation are logged every 14 days under the same lighting and magnification.
STEP 4ScoringResults are combined with ingredient analysis, price per month, refund terms and verified customer ratings.
Ingredients guide

What's Actually in the Bottle.

Peptides

Recommended

Myristoyl pentapeptide-17 and similar peptides support the keratin structure of the lash. Gradual, well-tolerated results.

Biotin & Panthenol

Conditioning

Strengthen and hydrate existing lashes, reducing breakage. Limited evidence for new growth on their own.

Prostaglandin analogs

Caution

Isopropyl cloprostenate and related compounds drive strong growth but can cause redness, lid darkening and pigment changes.

Castor & plant oils

Neutral

Add shine and flexibility. No measurable effect on length in our testing; may interfere with extension adhesive.

The big decision

Peptides vs Prostaglandins.

Almost every question we receive comes down to this choice. Prostaglandin analogs are pharmacologically active: they were discovered as a side effect of glaucoma drops and they work by extending the growth phase of the follicle. Peptides are signalling fragments of proteins that support the structure and nutrition of the lash without hormonal-type activity.

In our panel, the single prostaglandin product delivered the fastest and largest length gain, but also every recorded case of lid redness. The peptide products delivered slightly slower results with no side effects worth noting. For most buyers that trade-off favours peptides; for buyers who want maximum growth and accept the risks, it does not.

Prostaglandin analogsPeptide serums
MechanismSignals the follicle to stay in the growth (anagen) phase longerSupports keratin structure and follicle nutrition
Typical time to visible results3–4 weeks6–8 weeks
Maximum effectStrongest measurable length and density gainModerate to strong; depends on peptide blend and concentration
Common side effectsRedness, lid darkening, rare pigment change, drynessMild irritation in a minority of users
Sensitive eyes / contact lensesNot recommendedUsually well tolerated
Regulatory status in the USCosmetic; prescription bimatoprost is FDA-approved for hypotrichosisCosmetic
Products in this rankingGrandeLASH-MDQUALASH, RevitaLash, VEGAMOUR, OLAPLEX, The Ordinary, neuLASH, RapidLash
Buyer's guide

How to Choose a Lash Serum.

Eyelash growth serums fall into two groups. Prostaglandin-analog serums borrow their active ingredient from glaucoma medication and deliver the strongest measurable growth, but carry documented side effects. Peptide-based lash serums work more gradually by conditioning the follicle and supporting the lash's keratin structure, with a far lower rate of irritation.

For most people in the US buying over the counter, a peptide serum is the safer starting point. The products in this ranking were assessed on the same six criteria so you can compare a $14 drugstore serum and a $150 premium conditioner on equal terms.

Check the active ingredient first

Look for named peptides such as Octapeptide-2, Myristoyl Pentapeptide-17 or Biotinoyl Tripeptide-1. If the list includes isopropyl cloprostenate, dechloro dihydroxy difluoro ethylcloprostenolamide or any word ending in -prost, the product is a prostaglandin analog.

Calculate cost per month, not price per bottle

Bottle sizes range from 2 ml to 5 ml. A $60 serum that lasts three months costs more per year than an $80 serum that lasts eight. Divide price by the manufacturer's stated duration before comparing.

Look for independent testing

Brand-run consumer surveys are common; third-party lab studies are rare. A serum tested by an independent laboratory on a defined group, with a stated duration and sample size, is more reliable than a percentage from an unnamed survey.

Match the serum to your goal

If you want conditioning, shine and less breakage, a biotin and panthenol serum is enough. If you want measurable length and density, you need peptides or prostaglandins and a minimum 12-week commitment.

Application

How to Apply Lash Serum Correctly.

Most disappointing results come from inconsistent use rather than a weak formula. Testers in our panel who missed more than one application per week saw roughly half the length gain of consistent users.

  1. 1
    Start with a clean lash lineRemove all makeup and contact lenses. Serum applied over mascara or eyeliner residue is wasted.
  2. 2
    One thin stroke per eyeDraw the applicator once along the base of the upper lashes, like liquid eyeliner. More product does not mean faster results and raises the chance of irritation.
  3. 3
    Skip the lower lash lineEnough serum transfers when you blink. Applying directly to the lower lid increases the risk of redness and product in the eye.
  4. 4
    Apply every night for 12 weeksLashes grow in a 4–8 week cycle; results become visible only when new lashes complete a full cycle under treatment.
  5. 5
    Reduce to maintenanceAfter 12–16 weeks, most brands recommend 2–3 applications per week to hold results.
What to expect

A 12-Week Results Timeline.

Lashes grow in three staggered cycles, which is why nothing visible happens for the first month and why stopping early is the most common reason serums "don't work".

Week 0BaselineMacro photos and length measurements are taken. Lashes are typically 8–12 mm long on the upper lid, in three staggered growth cycles.
Weeks 1–2Conditioning phaseNo measurable growth yet. Testers usually notice lashes feel softer and shed less during makeup removal. Any irritation from a formula almost always shows up in this window.
Weeks 3–4First visible changeProstaglandin serums (GrandeLASH-MD) produce the first visible difference. Peptide serums are still working on the follicle; lashes may look darker and glossier.
Weeks 5–8Growth phaseNew lashes that started their cycle under treatment reach the tips. Most testers using the top five serums saw a clear difference in photos at week 6–8.
Weeks 9–12Full effectAll three lash cycles have now grown under treatment. Density and length peak; this is the point at which we score effectiveness.
Week 13+MaintenanceReduce to 2–3 applications a week. Stopping completely returns lashes to baseline over 8–12 weeks as the natural cycle replaces them.
Safety

Side Effects and How to Avoid Them.

Lash serums are applied millimetres from the eye, so tolerance matters as much as results. Across 42 testers and 10 products we logged every reaction, however minor. The list below covers everything that occurred plus the documented risks that did not appear in our panel but are well established in the literature.

The single most effective precaution is the simplest: apply a thin line to a clean, dry lid once a night, and stop at the first sign of persistent redness.

Redness and itchingThe most common reaction, usually in the first two weeks. It is more frequent with prostaglandin analogs and with alcohol-heavy formulas. Stop for a week; if it returns on restart, switch to a peptide serum.
Darkening of the eyelidA known effect of prostaglandin analogs. It fades over several months after stopping. Applying a thin line only, and wiping excess, reduces the risk.
Iris pigmentationRare and documented mainly with prescription bimatoprost, but the mechanism is shared by all prostaglandin analogs. People with light-coloured eyes should weigh this before choosing that category.
Dry eyesSome formulas contain preservatives or alcohols that migrate into the eye. Apply to dry lids, avoid the waterline and do not apply immediately before inserting contact lenses.
Pregnancy and breastfeedingNo lash serum has been tested in pregnant women. Most brands advise against use; prostaglandin analogs in particular should be avoided. Ask your physician.
Extensions and liftsWater-based serums are usually compatible with extensions if applied to the lid rather than the lashes. Oil-containing formulas can loosen adhesive. Wait 48 hours after a lash lift.
Alternatives

Serum vs Extensions vs Lash Lift.

A serum is not the only way to longer-looking lashes. Here is how it compares with the other options on cost, upkeep and what it does to your natural lashes.

OptionTypical US costWhat you getOur take
Lash serum$14–152 per bottleGradual, natural-looking increase in your own lashes; results last while you keep using it. Requires 12 weeks of consistency.Best long-term value; the only option that improves the lashes themselves.
Lash extensions$150–300 first set, $60–120 every 2–3 weeksInstant, dramatic length and volume. Adhesive and weight can thin natural lashes over time; regular fills are mandatory.Good for events; expensive and high-maintenance as a lifestyle.
Lash lift$80–150 every 6–8 weeksCurls and lifts existing lashes; makes them look longer without adding length. Chemical processing can dry lashes.Pairs well with a serum, which restores condition between lifts.
Prescription bimatoprost (Latisse)$100–150 per monthThe only FDA-approved treatment for inadequate lashes. Strongest results, but requires a prescription and carries the full prostaglandin side-effect profile.For medically diagnosed hypotrichosis; overkill for most cosmetic goals.
Castor oil$5–15Adds shine and flexibility. No controlled evidence of growth. Can clog lash-line glands and interfere with extension adhesive.Harmless as a conditioner; do not expect length.
FAQ

Common Questions.

Glossary

Lash Serum Terms Explained.

Anagen phase
The active growth phase of a lash, lasting roughly 4–10 weeks. Serums that lengthen this phase produce longer lashes.
Biotinoyl Tripeptide-1
A peptide combined with biotin, widely used in lash and brow serums to support keratin production and anchor the lash in the follicle.
Bimatoprost
A prescription prostaglandin analog, sold as Latisse for eyelashes. The only FDA-approved lash growth treatment.
Hypotrichosis
The medical term for inadequate or insufficient eyelashes.
Isopropyl cloprostenate
A synthetic prostaglandin analog used in some over-the-counter lash serums. Effective, but associated with the same side effects as prescription versions.
Myristoyl Pentapeptide-17
One of the most studied cosmetic peptides for lashes, reported in a manufacturer study to increase lash length after two weeks of use.
Octapeptide-2
A peptide used to stimulate keratinocyte activity at the follicle; a core active in the QUALASH formula.
Panthenol
Provitamin B5. A humectant that hydrates and adds flexibility, reducing breakage.
Prostaglandin analog
A class of compounds that mimic prostaglandins in the body. In lash serums they extend the growth phase but can cause pigment changes and irritation.
Telogen phase
The resting phase at the end of a lash cycle, after which the lash sheds and a new one begins to grow.