How can this be true when the whole point of laser hair removal is to eliminate hair?  Research has shown that there is the possibility that some patients can develop an increase in hair growth, also known as paradoxical hypertrichosis, following a treatment like laser/light therapy, although the side effect is relatively rare.  We have witnessed this occurance when selective clients came to us after having previously been treated with laser hair removal. These clients were of Mediterranean complexion (Fitzpatrick 4 or higher) and had a substantial number of laser treatments, resulting in visually significant increased facial hair growth.

What could cause such a reaction? One current theory is that the fine vellus hairs, usually dark hairs, are stimulated to grow because there is a less than therapeutic effect on these hairs, making them thicker and longer. (Willey, 2007)
Another theory looks at the use of low-level laser therapy (LLLT) where the energy level of the laser is too low to destroy the hair follicle, and subsequently stimulates growth factors leading to increased amounts of hair growth, clinically known as laser induced hypertrichosis. (Gagnon,L. 2014). Since medical practitioners must be extremely careful when treating pigmented skin with lasers, increased hair growth is another important reason to refer these clients to an electrologist, who can remove these hairs permanently and safely.   


Resources:
Gagnon, L. (2014) Dermatology Times, April 21: 1-3.
http://www.ncbi.nlm.nih.gov/pubmed/159 65427
Willey, A.  et al., Lasers Surgical Medicine (2007) Apr;39(4): 297 - 301.