Guide

The IPL treatment schedule, and the biology behind it

Every protocol in this category looks arbitrary until you understand the hair growth cycle. Then it becomes obvious why weekly, why twelve weeks, and why skipping sessions costs more than the sessions you skipped.

By Selena H. · Published October 13, 2026

Illustrative photograph, not a picture of a specific device.

The biology

The growth cycle explains everything

Hair does not grow continuously. Each follicle cycles through three phases:

Anagen - active growth. The hair is attached to the follicle's growth structures and melanin content is highest. This is the only phase in which IPL can do meaningful damage.
Catagen - transition. The follicle begins to detach.
Telogen - rest. The hair is no longer attached and the follicle is dormant. A pulse here does essentially nothing useful.

At any moment, only a fraction of the follicles in an area are in anagen. That single fact drives the entire protocol: one session can only affect the follicles that happen to be in the right phase on the day.

The schedule

Why weekly, then spaced out

Weekly sessions catch different cohorts of follicles as they rotate into anagen. Over a course of weeks, you progressively work through the population.

Manufacturer protocols vary within a consistent shape:

Device	Published protocol
Braun Silk-expert Pro 5	Weekly for the first phase; Braun quotes first results after three weekly uses and up to a year of hair reduction with maintenance
Ulike Air 10	Weekly through the initial course, then maintenance; four modes allow faster passes
Philips Lumea 9900	Initial weekly phase then monthly maintenance; publishes per-area times (lower leg 8.5 min, underarm 2.5, bikini 2, face 1.5)
General pattern	Weekly for 4-12 weeks, then maintenance every few weeks indefinitely

Follow the protocol published for your specific device. Where manufacturers differ, the manual that came with your handset wins.

The rule people break

Shave, never wax or epilate

Shave before each session. Hair above the skin absorbs energy that was meant for the follicle, and it singes, which is unpleasant and wasteful.

Never wax, epilate or thread between sessions. All three remove the hair from the follicle, and the hair is the thing that carries the pulse down to the growth structures. Remove it and the session accomplishes nothing - you will have done twelve weeks of treatment on empty follicles.

Consistency

What missing sessions actually costs

Missing a week is not simply a week's delay. The follicles that were due to be in anagen that week rotate out, and you catch them next time round - or the time after. The effect compounds across a course, and the usual outcome is patchy results that people attribute to the device.

This is why we weight session speed so heavily in our reviews. The Braun's both-legs-in-five-minutes claim and the Philips per-area times are not vanity metrics; they are the difference between a schedule you keep and one you abandon in week four.

After the course

What maintenance means

Maintenance is indefinite. There is no completion point in home IPL: you reach a level of reduction you are happy with and then top up every few weeks to hold it.

Hormonally influenced areas - the face in particular - typically need more frequent maintenance than legs, because the hormonal signal driving terminal hair growth is unaffected by anything a handset does. Facial IPL covered properly.

What to expect

A realistic timeline

When	What typically happens
Session 1	Nothing visible. Treated hairs may shed over the following one to three weeks.
Weeks 2-3	Shedding becomes noticeable. This is not regrowth and is not a problem.
Week 3-4	Braun quotes first visible results around here with weekly use.
Weeks 4-8	Density visibly reducing; regrowth finer and slower.
Weeks 8-12	End of the initial course for most protocols. Assess here.
Ongoing	Maintenance every few weeks, indefinitely.

A general shape based on published manufacturer protocols. Coarse hair and hormonally influenced areas commonly take longer.

The checklist

Before every session

Shave the area and clean it. No lotion, no deodorant, no self-tan residue.
Check for a tan. A tan you acquired since your last session changes your suitability. Why.
Patch test if anything has changed - a new area, a higher setting, a new medication.
Plan your pattern so you cover the area without overlapping. Overlapping pulses are how burns happen.
Work in good light so you can see where you have been.
Skip the session if the skin is irritated, broken or sunburned. One skipped week beats a damaged area.

Afterwards: no heat, no hot showers, no sauna, no sun on the treated area for the period your manufacturer specifies, and sunscreen on anything exposed.

FAQ

Questions people actually ask

How often should you use IPL?

Weekly through the initial course, typically four to twelve weeks depending on the device, then maintenance every few weeks indefinitely. Weekly spacing catches different cohorts of follicles as they rotate into the anagen growth phase.

Why can't you wax between IPL sessions?

Waxing, epilating and threading remove the hair from the follicle, and the hair is what carries the pulse down to the growth structures. Without it the session does nothing. Shaving is the only compatible method during a course.

How long until IPL shows results?

Braun quotes first results after three weekly uses. Most protocols run eight to twelve weeks before you assess properly. Shedding of treated hairs in weeks two and three is normal and is not regrowth.

What happens if you miss an IPL session?

The follicles due to be in the anagen phase that week rotate out and are caught a cycle or two later, so the course stretches and results come out patchier. Missing weeks costs more than the weeks themselves.

Do you have to keep doing IPL forever?

Yes, as maintenance. Home IPL produces reduction rather than removal, so you top up every few weeks to hold the result. Hormonally influenced areas such as the face usually need more frequent maintenance.

Sources