Why IPL Hair Removal Needs Multiple Treatments: The Science of Hair Growth Cycles

If you’ve ever wondered why IPL hair removal doesn’t remove every hair after one session, the answer is simple: not all of your hair is growing at the same time.

IPL works best when hair is in its active growth stage. Because only some hairs are in that stage during any given treatment, multiple sessions are needed to gradually target more follicles over time.

How IPL works

IPL stands for intense pulsed light. It uses broad-spectrum light to target pigment in the hair, and that light energy turns into heat, which damages the follicle and reduces its ability to keep producing hair.

This is why IPL works best on hair that is actively connected to the follicle. If a hair is in the wrong part of the growth cycle, the treatment is less effective, even if the hair is visible on the surface.

The hair growth cycle

Hair grows in repeating stages, and different hairs on the same area of your body can be in different stages at the same time.

• Anagen: the active growth phase, when the hair is still attached to the follicle and is most responsive to IPL.
• Catagen: the transition phase, when the follicle begins to shrink and detach from the hair.
• Telogen: the resting phase, when the hair is no longer actively growing and is less responsive to treatment.

That cycle is the real reason IPL needs repeated treatments. One session can only effectively target the hairs that are currently in anagen, while the rest will need to be treated later when they cycle back into that stage.

Why one treatment is not enough

A single IPL session does not fail because hair shows up afterward. It simply means other follicles were in a different phase and were not ideal targets yet.

That is why early results are usually partial. After the first treatment, hair reduction is often limited, and smoother, more noticeable results tend to come from completing a full treatment series rather than expecting a one-time transformation.

It’s also normal for treated hairs not to disappear immediately. Hair can shed gradually over days to weeks, which can make it seem like it is still growing even when the treatment has already worked.

Why treatments are spaced out

Sessions are spaced out to give a new group of hairs time to enter the active growth phase.

That is why IPL routines are usually designed over several weeks instead of several days. Treatment intervals can also vary depending on the area, since facial hair and body hair do not all grow at the same speed.

MimiSilk IPL and why consistency matters

What makes at-home IPL appealing is not just convenience, but consistency. Instead of relying on occasional appointments, users can follow a treatment schedule more easily at home, which is especially important because hair follicles are not all in the same growth stage at the same time. 

This is exactly why at-home IPL works best as a routine, not a one-time treatment. MimiSilk’s IPL devices are designed to be used regularly over a treatment period and then followed by maintenance as needed, which matches how hair follicles cycle naturally.

With consistent use, different groups of hair can be treated as they enter the active phase. Over time, that can lead to less dense regrowth, finer hair, and smoother skin rather than instant all-at-once removal.

It’s important to set realistic expectations. IPL is designed for long-term hair reduction, which means results usually build gradually, and occasional maintenance treatments may still be needed.

Why this matters before summer

Summer often makes people want faster results, especially for legs, underarms, bikini line, and facial hair. But IPL works best when you start early enough to stay consistent for several weeks, rather than waiting until the last minute.

That makes this one of the most important things to understand before starting: IPL is not a one-day fix. It is a process built around the biology of the hair cycle, and that is exactly why repeated treatments are part of getting better results.

Sources

American Academy of Dermatology. “Laser hair removal: FAQs.” https://www.aad.org/public/cosmetic/hair-removal/laser-hair-removal-faqs

Cleveland Clinic. “Laser Hair Removal: How it Works & What to Expect.” https://my.clevelandclinic.org/health/treatments/21757-laser-hair-removal

Almohanna HM, et al. “Integrative and Mechanistic Approach to the Hair Growth Cycle and Hair Loss.” PMC, 2023. https://pmc.ncbi.nlm.nih.gov/articles/PMC9917549/

Mayo Clinic. “Laser hair removal.” https://www.mymlc.com/health-information/tests-and-procedures/l/laser-hair-removal2/