Photodynamic hair removal
Photodynamic therapy (PDT) is an experimental method of epilation combining chemicals and radiation to induce controlled hair loss or hair reduction. A chemical is administered which selectively pigments a follicle‘s regenerative structures. Laser or other radiation selectively targets the darkened cells while sparing surrounding tissue. Theoretically could target any hair color.Commercial use is not expected in the foreseeable future.
Hair growth cells and cancer cells share some interesting characteristics: rapidly dividing with multiple potentials for differentiation. This is part of the reason many combinations of chemotherapy and radiation result in hair loss: they disrupt the same kinds of cellular activity.  It has been theorized that combinations of these drugs and radiation may be used to induce a controlled amount of hair loss or reduction.
Photodynamic therapy (PDT) has been useful in treating some types of cancers. [2, 3, 4] Certain chemicals have been observed to darken some types of skin cells,  which can then be selectively targeted by laser to induce apoptosis or “programmed cell death.”  Recent data suggests PDT may have uses in the treatment of acne as well. 
In addition, the presence or absence of certain genetic markers in mice such as p53 have been observed to be “on-off” switches for chemical/radiation induced hair loss.  Learning to manipulate genetic markers like these in conjunction with chemicals and/or radiation may lead to new hair reduction treatments.
This has been proposed as a theoretical possibility of hair removal, and in 1995 an experimental clinical trial was performed.  However, commercial use of the procedure is not expected in the near future.
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- Morton CA and others. Photodynamic therapy for large or multiple patches of Bowen disease and basal cell carcinoma. Archives of Dermatology. 2001 Mar;137(3):319-24.
- Guillen C and others. Photodynamic therapy for in situ squamous cell carcinoma on chronic radiation dermatitis after photosensitization with 5-aminolaevulinic acid. Journal of the European Academy of Dermatology and Venereology. 2000 Jul;14(4):298-300.
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- Hongcharu W and others. Topical ALA-photodynamic therapy for the treatment of acne vulgaris. Journal of Investigative Dermatology 2000 Aug;115(2):183-92.
- Botchkarev VA and others. p53 is essential for chemotherapy-induced hair loss. Cancer Research 2000 Sep 15;60(18):5002-6.
- Grossman MC, Wimberely J, Dwyer P, Flotte TJ, Anderson RR. PDT for hirsutism. Lasers in Surgery and Medicine (supplement) 7 : 44,1995.