Timing is everything in lash lifting. The difference between beautifully curled lashes and damaged, over-processed ones often comes down to just a few minutes. Yet processing times remain one of the most confusing aspects of at-home lash lifts, with kit instructions often providing broad ranges that leave users uncertain. This guide will help you understand the science behind processing times and develop the skills to time your treatments perfectly.
The Science of Processing
Understanding what's happening chemically during each step helps you appreciate why timing matters so much.
What the Lifting Solution Does
The lifting solution contains active ingredients (typically ammonium thioglycolate) that break the disulphide bonds in your lash hairs. These bonds are what give your lashes their natural shape. By breaking them, the solution allows lashes to be reshaped around the shield. The longer the solution remains on your lashes, the more bonds are broken.
What the Setting Solution Does
The setting solution (usually containing hydrogen peroxide or sodium bromate) reforms the broken bonds in their new curved position. This "locks in" the lift. If bonds aren't adequately reformed, the curl won't hold, and results will fade quickly.
The Balance
Successful lash lifting is about breaking just enough bonds to allow reshaping, then reforming them completely. Too few broken bonds means minimal lift; too many means damage. The setting time must be sufficient to fully reform whatever bonds were broken.
Factors That Affect Processing Time
Lash Thickness and Texture
This is the most significant factor in determining processing time. Lash hairs vary considerably in thickness between individuals:
- Fine, soft lashes: Process quickly (6-8 minutes per solution). These lashes have fewer protein bonds and less structure, so they respond rapidly to chemicals. Over-processing is a significant risk.
- Medium lashes: Standard processing (8-10 minutes per solution). The "average" lash type that most kit instructions are designed for.
- Thick, coarse lashes: Require longer processing (10-14 minutes per solution). More structure means more bonds to break. Under-processing is the common issue.
Lash Colour
Colour can be an indicator of lash structure. Lighter lashes (blonde, red, light brown) tend to be finer and process more quickly. Dark lashes often have more melanin and structure, requiring slightly longer times. However, this is a generalisation - always assess the actual texture of your lashes.
Previous Chemical Treatments
If your lashes have been lifted recently (within the past month or two), they may still have some residual effects from the previous treatment. Previously treated lashes often process slightly faster and carry higher risk of over-processing.
Solution Strength
Not all lash lift products are created equal. Professional-grade solutions are often stronger than consumer kits and require shorter processing times. Always read the specific instructions for your product and adjust from there.
Never Assume
Even if you've used a dozen different lash lift kits, always read the instructions for each new product. Processing time recommendations can vary significantly between brands and formulations.
Processing Time Guidelines
Lifting Solution Times
Use these as starting points and adjust based on your lash type and results:
- Fine lashes: 6-8 minutes
- Medium lashes: 8-10 minutes
- Thick lashes: 10-14 minutes
- Very coarse/resistant lashes: 12-16 minutes (with caution)
Setting Solution Times
Setting times are typically similar to or slightly shorter than lifting times:
- Fine lashes: 5-7 minutes
- Medium lashes: 6-8 minutes
- Thick lashes: 8-12 minutes
Start at the lower end of recommended times for your first treatment with any new product. You can always increase times in future treatments, but you cannot undo over-processing.
How to Determine Your Ideal Time
The Learning Approach
Finding your perfect processing times is a gradual process:
- First treatment: Use the minimum recommended time for your lash type. Accept that results may be subtle.
- Assess results: After 48 hours (once the lift has fully set), evaluate. Is the curl noticeable? Did it take evenly? Any signs of damage?
- Adjust next time: If results were too subtle, add 1-2 minutes. If lashes seem frizzy or over-curled, reduce time.
- Document everything: Keep detailed notes so you can refine your approach over time.
Visual Cues During Processing
Experienced technicians sometimes use visual cues to assess processing, though this is difficult to do on yourself:
- Lashes may begin to look slightly lighter or more translucent as bonds break
- Very fine lashes may start to appear slightly frizzy at the tips if over-processing begins
- The solution may change colour slightly as it reacts (product-dependent)
For at-home users, timing is more reliable than visual assessment. Set a timer and stick to it.
Common Timing Mistakes
Using the Same Time for Every Treatment
Your lashes change over time. Seasonal variations, health changes, and age can all affect lash structure. Stay attentive and adjust as needed rather than assuming what worked last time will work again.
Not Using a Timer
Estimating time while focusing on other aspects of the treatment leads to inconsistent results. Always use a timer. Most smartphones have timer functions that can alert you audibly.
Extending Time to "Boost" Results
If your lift isn't taking well, the solution is rarely to process longer. Issues like poor adhesion to the shield, inadequate product application, or resistant lashes require technique adjustments, not extended processing.
Rushing the Setting Step
After the drama of the lifting solution, some people shortchange the setting time. This is a mistake. Insufficient setting means bonds don't reform properly, and your curl will drop within days.
Signs of Over-Processing
Learning to recognise over-processing helps you adjust future treatments:
- Frizzy or kinked lashes: Lashes that look unruly rather than smoothly curled
- Overly tight curl: Lashes that curl back on themselves or look crimped
- Brittle texture: Lashes that feel dry and snap easily
- Premature shedding: Increased lash loss in the days following treatment
- Discolouration: Lashes appearing lighter or more transparent than before
If You Over-Process
There's no quick fix for over-processed lashes. Focus on intensive conditioning with serums and oils, avoid further chemical treatments until lashes have fully grown out (2-3 months), and learn from the experience to adjust times for next time.
Signs of Under-Processing
Under-processing is less damaging but still disappointing:
- Minimal visible lift: Lashes look almost the same as before treatment
- Quick fade: Any lift achieved drops within a week or two
- Uneven results: Some lashes lifted while others didn't respond
If under-processing occurs, you can repeat the treatment in 4-6 weeks with slightly longer times. This is always preferable to the damage caused by over-processing.
The Perfect Lift
When timing is right, lashes are beautifully curled, smooth in texture, and maintain their lift for 6-8 weeks. With practice and careful documentation, you'll find your ideal processing times and achieve consistent, stunning results.