New Study Shows Hair Regrowth in Home Laser Treatments

IPL and laser treatments from home are growing in popularity, but to what degree does hair regrowth occur after the end of treatment?  A new scientific study has been released with some interesting results.

What are Home IPL / Laser Devices?

The Silk'n SensEpil is one of the most popular home hair removal kits that are available on the market. This particular brand uses IPL technology.

Laser and IPL (Intense Pulsed Light) are both popular forms of hair removal that offer permanent hair reduction.  You can read about the difference between laser and IPL here.

Historically, these hair removal treatments were only available for consumers who went to professional salons, however recently a new breed of home devices have been cleared by the FDA as being safe for selling directly to the consumer for home use.

These devices are less powerful than the lasers and IPL devices that are used in professional salons, however there have been a number of studies to show that they are still effective at hair reduction.

Hair Regrowth Rates

Both laser and IPL hair removal (both at home and professionally) cause a certain amount of regrowth following the initial hair reduction.  

We don't yet fully understand all the factors that contribute to hair regrowth, however a recent scientific study has shed some light on the extent at which this regrowth occurs.

Study - 36 Females in Underarm Hair Removal (2014)

A recent study published in 2014 investigated the hair regrowth rates in 36 female patients after home laser hair removal treatment.

Test Details

  • All 36 women had skin type between 1 and 4 on the Fitzpatrick scale.  This means that their skin tone ranged from "white with no pigment" to "light / moderate brown".
  • The treatments were self administered by the participants on a weekly basis for a total of 8 weeks with a diode laser set to 810nm wavelength.  
  • Results were taken before each treatment and up to 3 months after the final treatment
  • Light to dark brown underarm hairs were treated in the study
  • Subjects shaved both underarm regions one week before each visit.
  • Median age of subjects was 32 years (range 22 - 44)

Results

There was a steady reduction of hair count in all participants of up to 59% while the remaining hairs were up to 38% thinner and 5% lighter.  Participants reported "moderately" to "much less hair".  This was result was sustained until one month after the final treatment.

However, interestingly, 3 months after the treatment stopped hair count gradually returned to the initial count and, on average, the hair count grew beyond the original amount by up to 29%.​

In plain Layman's terms - the participants experienced a reduction in hair count while they were actively treating the underarm region up until one month after the final treatment.

However when they stopped the hairs grew back to 29% more than the original amount counted before the first treatment.​

The following chart shows how the participants reacted to the home laser hair removal treatments week by week.  Only weeks 1 - 8 were treatment weeks, any weeks after this point were follow up sessions.

What Does this Study Tell Us?

It's very easy to jump to the initial conclusion that home laser hair removal devices cause an increase in hair count around 3 months after the patient stops using the device.

The problem is that this goes against a LOT of the other scientific data that has been published regarding laser hair removal.  While we do know that lasers can induce additional hair growth, it only happens in a very small number of cases.  This wouldn't be enough to account for the massive 29% average increase after 3 months.

How Can We Explain the Increase?

Temporary Transformation of Hair Stages

The power of home laser / IPL kits is much less than those used in professional salons. It is thought that the lower-power lasers reduce hair counts by transforming hairs from the growing phase to the resting phase whereas the high-powered lasers (such as those found in salons) heat the follicle enough to produce a more permanent transformation.

In plain English - home laser / IPL kits simply move hairs that are currently growing into a resting phase.​  If the treatment stops, then these hairs will convert back into the growing phase.  

One possible theory to explain the hair count increase after three months is that the hairs that were transformed into the resting stage from the treatment convert back into their growth stage on top of the new hairs that grow naturally.

Contradiction with Other Studies

There are a number of similar other studies that look at hair regrowth from home laser hair removal and none have reported increased hair counts.  So how can we explain why this study is different?  Here are two things to consider:-

  • Patients shaved before each treatment - Contrary to all other studies, this study only counted the active "growing" hairs because each patient shaved their underarms one week before each visit.
  • Counts were automatic rather than manual - this particular study used a computer program to count hairs while, in all other studies, hair counts have been manual. This is unlikely to have any baring on the results, though.

Summary of Other Studies that have Looked at Regrowth Rate on home laser / IPL Devices

So far there have been 3 controlled and 6 uncontrolled studies that have looked at the efficacy of home laser / IPL hair removal kits.  Here is a summary of their findings:-

  • During treatment patients received up to 70% reduction in hair count
  • Hair reduction of between 6% and 72% at 3 months after treatment
  • Hair reduction of between 41% - 87% at 6 months post treatment
  • Hair reduction of between 33% and 65% at 12 months post treatment

The Conclusion - Do Home Laser / IPL Machines Cause Increased Hair Regrowth?

Given all the evidence that's available - no.​

Naked male and female facing away from camera

The major flaw with this study is that patients weren't analysed after 3 months from the post treatment date.  This would have helped us to understand if the increased hair growth is temporary due to resting hairs moving back into the growth phase or if it's a more permanent side effect.

With all the evidence that's available at the moment, it seems highly unlikely that the 29% increase in hair growth is a long term result of home laser / IPL hair removal.  This would also be inconsistent with the large number of anecdotal evidence from people who have actually used these kits.

In fact, there is a large amount of evidence to support the efficacy of home based hair removal systems for up to 12 months after the end of treatment.

Here are some things that do appear to be the case, though:-

  • Home laser / IPL hair removal systems are not as powerful and thus seemingly effective than professional laser hair removal systems.  The degree to which this is true is still uncertain, but it doesn't seem to be hugely significant.
  • The lower fluence (power) in the home laser / IPL kits reversibly transform hairs from growing to resting whereas high-fluence lasers are believed to damage stem cells and induce a more long lasting effect
  • Home laser / IPL kits do work for most people although the degree of effectiveness does vary from person to person
  • For best results, continued use with the home laser is necessary
  • After stopping treatment hair regrowth will occur.  This usually doesn't happen before one month after the treatment.  However, after three months regrowth should be expected.
  • Home laser / IPL devices are safe with only minor temporary side effects having been reported.

Conclusion:- In light of all this evidence, home laser / IPL kits are a good purchase for people who want the convenience of hair removal from their own home, who would prefer a more longer lasting effect than other forms of hair removal (such as waxing / shaving) and who don't want the much larger expense of professional laser hair removal / electrolysis.

Resources

Paul
 

I'm a computer science graduate, have a passion for self development and created this site as a side project due to the lack of complete, understandable, helpful and truthful information about hair removal available online. Over the next few years, I want to develop this site into being the place to visit for hair removal consumer information. Got any questions? Write to us below:

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