Do Eyelash and Eyebrow Serums Actually Work?

My Honest Results as an Aesthetic Doctor with Obagi Nu-Cil

by Dr Caroline Warden NHS GP, cosmetic dermatology and aesthetic doctor in Hale, Cheshire

Eyelash and eyebrow serums have exploded in popularity over the past few years but do they ACTUALLY work? Or is it all just clever marketing?

Thankfully i’ve always had ‘OK’ eyelashes but as I can’t tolerate falsies/stick-ons for more then an hour and hated the process of an LVL eyelash extension so I was intrigued by serums.

I wondered if I could grow them naturally a touch longer or fuller but my scientific mind would need to know the evidence and see for myself!

Short answer: yes, many serums do work! When they contain the right ingredients, are applied correctly, and you give them enough time. In this blog post, I’ll break down how lash and brow serums work, what results you can realistically expect, how to use them safely, and I’ll share my personal experience using Obagi Nu-Cil Lash and Brow serums, plus what I noticed week by week.

How Do Lash & Brow Serums Work?

Most effective serums aim to support hairs through the natural growth cycle:

• Anagen (growth)

• Catagen (transition)

• Telogen (rest/shedding)

The goal is to support follicles in anagen for longer, reduce breakage, and improve the condition of the hair shaft so lashes/brows look darker, shinier, and more uniform.

There are two broad categories of active approaches:

1. Peptide + conditioning complexes
   These use multi-peptides, biotin, panthenol (vitamin B5), amino acids, and humectants like hyaluronic acid. They don’t alter the follicle’s biology as dramatically as prescription prostaglandin analogues, but they nourish, strengthen, and reduce shedding, often giving a fuller, healthier look over 6–12 weeks.

2. Prostaglandin analogue derivatives
   These can encourage longer anagen phases and visibly longer lashes. Some are available by prescription; others are included (in derivative form) in certain over-the-counter serums. They tend to produce faster, more dramatic lash length results for some people, but can bring a higher risk of sensitivity for others, especially around the eye.

Obagi Nu-Cil uses a multi-active, conditioning approach (their proprietary complex is designed to support follicle health and lash/brow quality).

In my experience, this gave me natural-looking density and better lash integrity without irritation.

What Results Are Realistic?

Let’s set healthy expectations:

• Lashes: Expect to start noticing changes around 6–8 weeks, with best results by 12–16 weeks. Improvements typically look like less shedding, better curl hold, and a thicker “fringe” effect (mascara suddenly looks better because you’ve got more uniform hairs to coat)

• Brows: Brows are slower. Expect 8–12+ weeks for clear gains in density and tail definition. You’ll likely notice fewer sparse patches first, then soft new growth that needs consistent grooming.

Consistency is the entire game.

My Personal Experience with Obagi Nu-Cil

I trialled Obagi Nu-Cil Eyelash Enhancing Serum and Nu-Cil Brow Serum consistently, once nightly.

Weeks 1–2

• Lashes: No visible changes yet, but my mascara was flaking less. No stinging or redness.

• Brows: Zero visible change (completely normal at this stage).

Weeks 3–4

• Lashes: Subtle improvement in how my curl held throughout the day. The outer third looked slightly more “fanned”. Still very natural.

• Brows: The front (bulb) looked softer and a touch more even, as if tiny new hairs were filling in.

Weeks 6–8

• Lashes: Noticeably fuller lash line, especially at the outer corners. I could get away with a single coat of mascara for daytime and it looked polished. Lash loss when removing eye makeup was reduced.

• Brows: Better density through the arch; those sparse mid-sections were less obvious. I started needing less pencil to even them out.

Weeks 10–12

• Lashes: Best results. A denser lash fringe with a small but definite improvement in length. The look remained natural and not “extension-like”, but a healthier, thicker set of lashes that frames the eye beautifully.

• Brows: Tail definition improved, and overall texture looked smoother and glossier. Makeup sat better and I needed less product.

Side Effects?

I didn’t experience irritation, redness, or itching. No darkening of the skin along the lash line. (That said, everyone’s skin and eyes are different (more on safety below.)

Bottom line from my trial: Obagi Nu-Cil gave me noticeably fuller, healthier-looking lashes and brows with a very low irritation profile, provided I kept up nightly use.

How to Use Lash & Brow Serums for Best Results

1. Start with a perfectly clean canvas.
   Remove all eye makeup and cleanse thoroughly. Oil residue can block absorption.

2. Apply a thin line at the base of the lashes.
   For lash serum, one dip is usually enough for both eyes. Apply like eyeliner: right where the lashes meet the skin.

3. Brows: target the sparse zones.
   Sweep through the entire brow, then add an extra pass to tails or gaps.

4. Nightly is ideal.
   Consistency > volume. Don’t double-dose to “catch up”.

5. Wait a few minutes before layering skincare.
   Let it absorb before using eye cream or brow gels.

6. Be gentle with removal.
   Rough rubbing causes mechanical lash/brow loss. Use a soak-and-press method with a mild remover.

Safety & Side Effects: What to Know

Most peptide-based serums are well tolerated. Still, keep these in mind:

• Possible irritation: stinging, redness, itching along the lash line or brow area. If this occurs, pause for 2–3 days and retry every other night. If irritation persists, stop.

• Contact lens wearers: apply after removing lenses at night.

• Pigmentation changes: A small subset of users may notice mild darkening of the skin where applied, particularly with prostaglandin-derived formulas. If you see this, stop and speak to a clinician.

• Pregnancy & breastfeeding: play it safe and avoid unless cleared by your healthcare provider.

• Glaucoma/ocular history: if you use prescription eye drops or have a history of eye conditions, check with your ophthalmologist first.

Lash vs Brow Serums: Are They Interchangeable?

Even though the ingredient philosophies overlap, lashes and brows aren’t identical:

• Lashes benefit from ultra-precise, thin-line application to avoid the eye’s mucosa.

• Brows need a wider, comb-through application to reach multiple directions of hair growth and the often-sparse tails.

Using dedicated formulas designed for each area gives you the best chance of great results with minimal irritation.

Who Is a Great Candidate?

• You notice increased shedding or your lashes/brows feel less dense than 1–2 years ago.

• You’ve stopped lash extensions and want to rehab your natural lashes.

• You want a natural, low-maintenance boost without makeup.

• You’re prepping for an event and have 8–12 weeks to build results.

Who Should Skip or Seek Advice First?

• You’re pregnant or breastfeeding.

• You have active eye infections, blepharitis flares, or eczema on the lids.

• You have significant ocular history (glaucoma, eye surgeries)

Why I Like Obagi Nu-Cil for Clinic Patients

From a practical, clinic-friendly perspective, I appreciate that Nu-Cil:

• Prioritises conditioning + strength for a natural look.

• Plays nicely with sensitive eyes (in my experience and with my patients).

• Has easy, precise applicators for both lashes and brows.

• Works well alongside a gentle eye-area skincare routine (SPF on the lids by day, light hydrating eye cream away from the lash line at night).

It’s an great choice for people who want credible, cosmetic-grade results without venturing into prescription territory.

Practical Tips to Maximise Your Results

• Photograph your progress at weeks 0, 6, and 12 in the same lighting. It’s motivating and keeps expectations realistic.

• Tame inflammation: if your eyelids tend to be reactive, keep fragrance away from the eye area and use a bland, ophthalmologist-tested remover.

• Mind your mascara and brow gels: tubing mascaras and flexible-hold brow gels reduce tugging at removal.

• Don’t forget nutrition: adequate protein, iron, B-vitamins, and essential fatty acids support hair quality from the inside out.

• Maintain, don’t abandon: once you reach your “happy place,” drop to every other night rather than stopping completely. Hair cycles continue; maintenance preserves gains.

Frequently Asked Questions

How long before I see results?

Lashes often show change at 6–8 weeks, with best results by 12–16 weeks. Brows are slower: 8–12+ weeks.

Will my lashes/brows go back to “before” if I stop?

Yes—over several weeks to months, as your hair cycles naturally. Maintain with every-other-night use once you’ve reached your goal.

Can I use lash serum with extensions or lifts?

Yes, but pause for 48–72 hours post-procedure and avoid saturating the adhesive area. Always follow your lash tech’s aftercare.

Will serums change my eye colour?

That concern relates primarily to certain prescription prostaglandin formulas used inside the eye for glaucoma. Cosmetic, over-the-counter lash serums are applied to the skin at the lash line and, when used correctly, have a very low risk. If you notice any unusual changes, stop and seek advice.

Can I use lash serum on my brows (or vice versa)?

Some formulas are safe across both, but brow-specific serums usually have different applicators and texture for better spread. I recommend using the dedicated versions.

Is Obagi Nu-Cil safe for sensitive skin?

It’s been well tolerated in my experience. Introduce slowly (every other night for the first week) if you’re reactive, and avoid applying to broken or irritated skin.

The Verdict: Do Lash & Brow Serums Work

Yes—when you choose a credible formula and use it consistently. Eyelash and eyebrow serums won’t give an “extension” look overnight, but they can deliver healthier, fuller, better-behaved natural hairs that make everything—from bare-faced days to five-minute makeup—look more polished.

For me, Obagi Nu-Cil produced a noticeably fuller lash line and denser brows by the 8–12 week mark, with no irritation and a very natural finish. If you’re ready for a subtle-to-significant boost without the maintenance of extensions, it’s a smart, clinic-grade place to start.

Ready to Try It (and Do It Right)?

If you’d like personalised guidance, whether you’re a sensitive-skin wearer, transitioning from extensions, or need a brow rehab plan I can tailor a simple routine and realistic timeline for you. Book a consultation at my Hale clinic and we’ll set you up with an eye-safe, results-focused plan using Obagi Nu-Cil and gentle, supportive skincare so you actually see the difference in 8–12 weeks.

Final thought: Lashes and brows are tiny, but the confidence they add is not. If you’re patient and consistent, a well-formulated serum like Obagi Nu-Cil can absolutely earn a place in your routine.

Book a consultation today

Dr Caroline Warden is an experienced NHS GP and aesthetic doctor. She has been a medical doctor for over 18 years. Her Skin and Aesthetic Clinic is located in Hale, Cheshire

Whether you're new to aesthetic treatments or ready to refine your routine, her bespoke skin assessments are the best place to start. She’ll design a tailored plan based on your skin goals, lifestyle, and timeline.

Our main Hale clinic is local To:

Alderley Edge, Altrincham, Bowdon, Bramhall, Hale Barns, Knutsford, Manchester, Mobberley, Sale, Timperley, Urmston, Wilmslow, Handforth, Poynton, Cheadle, Didsbury, Warrington

Our satellite Disley clinic on Thursday nights at Scott, Skin & Co, is local to:

New Mills, High Lane, Marple, Mellor, Whaley Bridge, Hayfield, Stockport

References and Further Reading

1. Obagi’s Lash & Brow Serum Set page (includes both lash + eyebrow serums)
   https://www.obagi.com/products/obagi-lash-and-brow-serum-set Obagi

2. Press release about Nu-Cil’s clinical study results (16-week double-blind study)
   https://www.prnewswire.com/news-releases/obagi-medical-introduces-nu-cil-eyelash-enhancing-serum-clinically-proven-to-reveal-revolutionary-lashes-from-root-to-tip-301350496.html PR Newswire

3. Aesthetics Journal article summarising Obagi’s clinical trial outcomes
   https://aestheticsjournal.com/news/obagi-medical-releases-new-nu-cil-eyelash-serum/ Aesthetics Membership

4. Cityskin Clinic page summarising clinical trial metrics (e.g. % improvements)
   https://cityskinclinic.com/about-us/contact-us/products/obagi-skincare/obagi-nu-cil-eyelash-enhancing-serum/ City Skin Clinic