Laser hair removal clinical data

Laser hair removal terms and concepts

The new uses of lasers in the 1960s captured the imagination of both scientists and the general public. Lasers also captured the imagination of the hair removal industry, who began attempting hair removal almost as soon as dermatologists and researchers began experimenting on living tissue.

  • Wave 1 lasers: 1960 to 1969

The first lasers used for dermatology in the mid to late 1960’s emitted a continuous wave, but this was not practical for hair removal, since the beam could not be controlled well enough to avoid collateral skin damage. The development of the Q-switch (similar to a camera shutter) allowed laser energy to be emitted in controlled pulses.

  • Wave 2 lasers: 1969 to present

Early laser-like devices (see photoepilators) selectively targeted individual follicles by delivering energy through a wire-thin fiberoptic probe (and later through a penlight-type device). This device was rushed to market without adequate testing of effectiveness. It was marketed illegally as painless and permanent until FDA stepped in. These devices turned out to be tedious to use, logistically difficult to maintain the probes, and ineffective for permanent hair removal.

  • Wave 3 lasers: 1979 to present

As with electrolysis, the early published clinical data on laser hair removal involved the successful treatment of ingrown eyelashes. [1] This led to research and even a commercial attempt at a device using an argon laser for general market hair removal. This device was rushed to market without adequate testing of effectiveness, and it turned out to be tedious to use and ineffective for permanent hair removal.

Other researchers began using lasers for dermatological procedures and found them useful for removing some kinds of tattoos and for the treatment of some kinds of vascular lesions. In some instances, it was observed that hair loss occurred in treated areas, which led to experiments in epilation in animal models and later human subjects in the early 1990’s.

  • Wave 4 lasers: 1995 to present

In 1995, one century after the discovery of x-rays, FDA cleared the first laser for hair removal in the US, the SoftLightℱ Nd:YAG by ThermoLase. [2] This device was rushed to market without adequate testing of effectiveness. It was marketed illegally as painless and permanent until FDA stepped in. It uses a carbon-based lotion as a chromophore. This lotion was rubbed into the skin following waxing, with the hope it would penetrate the follicle. The laser would then rapidly heat the carbon, causing a shock wave of energy that had the potential to damage nearby cells. This process was found to be more complicated and less effective than targeting chromophores that occur naturally in the skin.

The device was sold to physicians and treatments were offered in a chain of proprietary clinics called Spa Thira, primarily in affluent communities. Consumers basically paid to be guinea pigs. By the time a medical paper appeared in 1997 which observed full regrowth of all hair [3], consumers had already spent hundreds of thousands of dollars on treatments. They quickly shifted their marketing strategy away from permanent hair removal to a “hair-management strategy,” but word was beginning to get out.

In 1998 a class action suit was brought against the company by a consumer alleging ThermoLase “advertised SoftLight laser hair removal as long lasting with the knowledge that such treatments did not achieve that result.” [4] ThermoLase quietly settled out of court later that year. In 1999, following other lawsuits and an annual loss of over $41 million, they began closing or selling their spas. [5] In 2000, with the stock down 92% from its high, ThermoLase was folded back into its parent company, which no longer manufactures or markets SoftLight in the U.S.

  • Wave 5 lasers: 1997 to present

In 1997 FDA cleared several types of devices that target melanin in the hair (see also flashlamps). As with the earlier devices, these devices were rushed to market without adequate testing of effectiveness.

Incremental improvements in equipment since 1997, such as more ergonomically-designed handpieces and methods of epidermal cooling, have made treatment generally more tolerable and reduced the likelihood of some side effects. The publication of clinical observations have also led to more optimized treatment parameters, but understanding of lasers and their long-term effects on hair and other skin structures is still in the early stages.

Current laser consumer issues: “A big problem brewing”

This quote is taken from a letter by Rox Anderson M.D., one of the major figures in medical laser research. He has written extensively on lasers in dermatology [6] and in hair removal in particular. I have quoted extensively from his comments below:

“Unfortunately, there is relatively little good, hypothesis-driven research on lasers in dermatology. These studies are expensive and slow to perform, analyze, present, and publish. The laser companies are quick to promote their new devices and procedures, even before efficacy and safety are well established, and before a specific FDA clearance is given.”

“Self-promotion is also common among laser practitioners, especially after laying out a small fortune for some new device. In the long run, their reputations (and ours) will suffer. Fooling the public into buying something of little value, is a very old trick.”

“Hippocrates knew this when making his famous oath… Does “first, do no harm” extend to a prospective patient’s bank account? Does it include the loss of trust suffered after receiving a series of costly, ineffective treatments? The answer is, yes.”

“When poorly researched before use on patients, cosmetic lasers or anything else are no different than the infamous patent medicines of the 19th century… But, what can be done about the decrepit standards for quality of introducing new aesthetic laser applications?… Specifically, I think companies should find it difficult to get a “general” [FDA] 510k clearance and then sell a device for some specific, unproven new procedure.”

“But the problem lies mainly with us, the professionals. We should simply refuse to believe infomercials over peer-reviewed studies.” [7]

Lack of consensus about effectiveness

Recent medical overviews of laser hair removal present widely differing opinions regarding the status. Some view it as “a promising but still faltering medical field,” [8] while others proclaim it’s “beyond the experimental stage.” [9] Some other examples:

“From this review of the literature, we conclude that laser hair removal does not at the moment have a permanent or convincing long-lasting effectiveness.” [10]

“During the last few years the fast development of different laser and laser-like systems for photoepilation and their one-sided representation in media has led to confusion among physicians and patients.” [11]

“Aggressive marketing of [lasers] has contributed to their popularity among patients and physicians. However, significant controversy and confusion surrounds this field… Although the field of optical hair removal is still in its infancy, initial reports of long-term efficacy are encouraging.” [12]

“As the field develops, a better sense of the effectiveness of laser hair removal will evolve and reasonable expectations will be determined.” [13]

“Although the amount of unwanted hair in a treated area can be effectively diminished, it is unclear if complete elimination of unwanted hair from any anatomic area can be achieved with any of the existing systems… There are very little published data on most of the lasers… The optimal treatment parameters, which may vary with anatomic site and skin type, have not been clearly established for any of the systems.” [14]

Optimizing treatment

Because lasers were rushed to market without a full understanding of their capabilities and limitations, it’s vital that researchers, practitioners, and consumers continue to make their experiences known to the public.

Skin cooling continues to be improved, [15, 16, 17] as does pain management [18, 19], although the risks of side effects have not been eliminated. Following a consumer death in 2000 due to a combination of pain medications prior to laser hair removal, [20] I have put together an overview of hair removal pain management. [21]

Standardizing terminology and performance standards

With everyone offering up arbitrary definitions in published data [22, 23, 24] and even on websites like this, it’s very confusing for consumers to judge long-term effectiveness and safety. In addition, FDA currently has no performance standard for epilators. They simply accept or reject definitions submitted by each manufacturer. This has led to multiple standards for what is permanent, which also confuses consumers. [25] If FDA is going to regulate labeling regarding use of the term “permanent,” there needs to be industry consensus on what this means, preferably a year or more follow-up with several hundred subjects participating in controlled multi-center studies.

Who gets to use laser?

The biggest issue at the time of this writing is who will control the use of this technology. Physicians, electrologists, and beauticians have all staked their claims, and it’s being left to each state to decide. [26] As expected, one survey showed that physicians feel they should maintain control of the device, and some non-physicians have stated they are qualified to own and operate lasers. [27]

As with x-ray 100 years earlier, use of dermatological lasers is in danger of being rapidly debased into a cosmetic procedure. Self-proclaimed “laserologists” have set up “training institutes” for beauticians and other non-physicians. Some even offer laser hair removal treatments to consumers without direct medical supervision.

There is currently a legislative push in some areas to make lasers available for purchase to non-physicians, proposed by those who stand to gain financially. Some argue this will make laser hair removal more widely available and drive down prices for consumers. Some consumer activists (including myself) have concerns that the likelihood of injury and quackery will increase if these devices are widely available to non-physicians. For instance, several of the parties pushing to make laser available to non-physicians in Florida are contributors, members and/or moderators of non-recommended promotional site Kitty’s Consumer Beware. [28]

As with Dr. Anderson, Christian Raulin, M.D., another pioneering laser researcher, states the issue of laser training is “a serious problem.” He notes: “Anyone, including healers, hair stylists, tattoo artists, and cosmeticians, can buy lasers and then advertise for their services. There are no legal requirements for training, no quality control measures, no official quality standards or guidelines… We must demand the extensive scientific evaluation of new and existing systems; objective and trustworthy marketing by laser manufacturer; well-founded training for laser operators; and legislation which restricts the use of lasers to physicians alone. [29]

Pushing for more published data

As always, the best hope for consumers comes is that researchers and physicians continue to make their findings known in peer-reviewed journals. This is the only way to combat the hype rampant in the mainstream press, the manufacturer and practitioner promotional materials, and in the unreliable anecdotal reports from consumers, as discussed in my section on recommended and non-recommended information sources.


  1. Berry J. Recurrent trichiasis: treatment with laser photocoagulation. Ophthalmic Surgery 1979 Jul;10(7):36-8.
  2. FDA Docket K950019. 5 April 1995. See summary (requires Adobe Acrobat).
  3. Nanni CA, Alster TS. Optimizing treatment parameters for hair removal using a topical carbon-based solution and 1064-nm Q-switched neodymium:YAG laser energy. Archives of Dermatology 1997 Dec;133(12):1546-9.
  4. Tester v. ThermoLase, Calif. Superior Court (S.F. County, case # 995285)
  5. TLZ 1998 Annual Report and SEC 10K, 18 December 1998.
  6. Anderson RR. Lasers in dermatology–a critical update. Journal of Dermatology. 2000 Nov;27(11):700-5.
  7. Anderson RR. Response to “Letter to the Editor.” Lasers in Surgery and Medicine 28:102 (2001)
  8. Paquet P, Pierard GE. [Laser-assisted hair removal: realities and calculations]. Revue Medicale de Liege. 1999 Sep;54(9):739-45. French.
  9. DiBernardo BE, Perez J, Usal H, Thompson R, Ferraro FJ, Fallek SR. Laser hair removal. Clinics in Plastic Surgery. 2000 Apr;27(2):199-211.
  10. Haedersdal M, Matzen P, Wulf HC. [Laser epilation. A systematic review of evidence-based clinical results]. Ugeskrift for Laeger. 2000 Dec 11;162(50):6809-15. Danish.
  11. Raulin C, Greve B. [Current status of photoepilation]. Hautarzt. 2000 Nov;51(11):809-17. German.
  12. Ort RJ, Anderson RR. Optical hair removal. Seminars in Cutaneous Medicine and Surgery. 1999 Jun;18(2):149-58.
  13. Hobbs L, Ort R, Dover J. Synopsis of laser assisted hair removal systems. Skin Therapy Letter. 2000;5(3):1-5.
  14. Lawrence WT. Hair removal laser and nonlaser light systems. Plastic Surgery Educational Foundation DATA Committee. Plastic and Reconstructive Surgery. 2000 Jan;105(1):459-61. Available online through PubMed
  15. Haas AF. Use of a unique cooling gel applied prior to laser hair removal. Surgery. 2000 Nov;26(11):1045-6.
  16. Zenzie HH, Altshuler GB, Smirnov MZ, Anderson RR. Evaluation of cooling methods for laser dermatology. Lasers in Surgery and Medicine. 2000;26(2):130-44.
  17. Altshuler GB, Zenzie HH, Erofeev AV, Smirnov MZ, Anderson RR, Dierickx C. Contact cooling of the skin. Physics in Medicine and Biology. 1999 Apr;44(4):1003-23.
  18. Eremia S, Newman N. Topical anesthesia for laser hair removal: comparison of spot sizes and 755 nm versus 800 nm wavelengths. Dermatologic Surgery. 2000 Jul;26(7):667-9.
  19. Altman DA, Gildenberg SR. High-energy pulsed light source hair removal device used to evaluate the onset of action of a new topical anesthetic. Dermatologic Surgery. 1999 Oct;25(10):816-8.
  20. Jackman, T. “Man’s Death After Visit To Clinic Spurs Suit” Washington Post, 31 January 2001, p. B1
  21. Please see for a discussion of pain management issues.
  22. Liew SH, Gault DT. Laser hair removal: the subjective hair-free interval as a simple outcome measure. British Journal of Plastic Surgery. 1999 Jun;52(4):322-3.
  23. Kobayashi T. Electrosurgery using insulated needles: epilation. Journal of Dermatologic Surgery and Oncology 1985 Oct;11(10):993-1000. p. 995.
  24. Dierickx CC. Hair removal by lasers and intense pulsed light sources. Seminars in Cutaneous Medicine and Surgery. 2000 Dec;19(4):267-75. Dierickx discusses “unwanted pigmented hair” here, avoiding a discussion of ineffective laser results on unpigmented hair. This follows her 1998 article proclaiming permanent hair removal by normal-mode ruby laser, but defining success based on “miniaturization” of pigmented terminal hairs only, and not complete hair removal. See the section on “permanent hair reduction” for details.
  25. FDA Docket K892514, 8 August 1990. In it, FDA reviewer Paul Tilton allowed 9 weeks as a performance standard for permanent hair removal. Docket 99P-1614 contains an extensive critical analysis of the Tilton decision. This scientifically unsound standard has been subsequently proposed in laser 510(k) submissions to FDA, but fortunately they are not allowed to use 9 weeks for permanence. The Tilton decision is an unfortunate footnote in the history of hair removal regulation and a triumph of quackery over good science.
  26. Crawley MT, Weatherburn H. Application of regulations to cosmetic lasers in private practice. Journal of Radiological Protection. 2000 Sep;20(3):315-9.
  27. Wagner RF Jr, Brown T, McCarthy EM, McCarthy RA, Uchida T. Dermatologist and electrologist perspectives on laser procedures by nonphysicians. Dermatologic Surgery. 2000 Aug;26(8):723-7.
  28. See the page on information sources for details on why Kitty’s Consumer Beware is a non-recommend source of hair removal information.
  29. Raulin C, Greve B, Raulin S. Ethical considerations concerning laser medicine. Lasers in Surgery and Medicine 28:100-101 (2001)