(IPL), is a technology aimed at producing light of high intensity during a very short period of time. It involves specific lamps together with capacitors whose rapid discharge provides the high energy required.

It is most commonly employed by medical practitioners and estheticians, is a method of hair removal from the body. It involves the use of a specially constructed xenon flash lamp and focusing optics.

The Intense Pulsed Light hair removal process has become very popular due to its cheaper and faster procedure compared to laser hair removal. The comparison of effectiveness between Intense Pulsed Light and Laser Epilation is debated by scientists, equipment manufacturers and practitioners, but results are generally accepted to be roughly equivalent. It is also used for the treatment of the skin in a process known as photorejuvenation.

Intense pulsed light (IPL) or flashlamp therapy is a non-invasive and non-ablative treatment that uses high intensity pulses of visible light to improve the appearance of the following skin problems:
Vascular lesions including spider angiomas, port wine stains, broken facial veins, rosy cheeks, rosacea and red thread veins of the legs
Freckles and age marks
Facial lines and wrinkles
Removal of unwanted dark hair

Hair removal mechanics

The focused, broad-spectrum light is applied to the surface of the skin by way of either a hand-held wand or an articulated arm. This light travels through the skin until it strikes the hair shafts or the bulb (root) of the hair. The bulb is usually where the highest concentration of melanin is located, as opposed to the rest of the hair shaft. As the light is converted to heat energy, the bulb and most of the hair shaft are instantly vaporized. The intense heat radiated by the hair also destroys the hair-producing papilla or the entire hair follicle. It is also claimed that direct light-heat conversion occurs directly in the darker colored capillaries that bring nourishing blood vessels to the follicle.

IPL technology is also employed in the treatment of medical disorders of the skin including:

Sun damage induced dyspigmentation and vascular changes
Poikiloderma of Civatte
Acne Rosacea
Broken capillaries/telangiectases
Vascular and pigmented birth marks

In terms of rosacea, IPL offers one of the few effective treatments to relieve the facial redness associated with the disorder. Such treatment may be administered by a dermatologist or other medical specialist with experience treating skin disorders. This new technology incorporates 'dual mode filtering' and other important advances which result in safer and more effective treatment than older systems designed for hair removal.

The pulses of light produced by IPL equipment are very short in duration, so discomfort and damage to non-target tissues is minor. Most people who undergo IPL epilation only experience slight irritation similar to that of a minor sunburn though under certain circumstances, blisters may occur. Men undergoing the procedure experience greater discomfort as male body hair is generally thicker than women's. Depending on the instrument settings and intensity, treating sensitive areas such as the chest and face can result in pain comparable to waxing the same areas; however this pain dissipates immediately. The light that emanates from the IPL wand is filtered to remove any ultraviolet components, eliminating the possibility of UV skin damage.

IPL's (Intense Pulsed Light) work more directly on the top layers of the skin and do not penetrate deep enough to damage hair germ cells, without potential damage to the epidermis.

What does the procedure involve?

Prior to the procedure your specialist practitioner should explain the process to you and clearly define your expectations of the treatment. They should be able to tell you whether or not the results you are looking for will be achievable using this method. It is important that the correct diagnosis has been made by your doctor prior to treatment.

IPL treatments are normally straightforward. Make sure the technician has been properly trained and is experienced in IPL therapy.

Avoid sun exposure in the days and weeks before and after treatment.
A topical anaesthetic may be applied to the area but is not usually necessary.
Cold gel is applied to the area being treated. IPL devices often have integrated cooling systems.
The smooth, glass surface of the IPL treatment head is applied to the skin, delivering precise pulses of light to the area being treated.
Treatment sessions usually last about 20 minutes. A course of 4-6 sessions every 3-6 weeks may be needed to achieve desired results.
Most patients can return to work immediately after treatment.

Throughout the treatment session the patient must wear protective eyewear. IPL treatments are relatively painless compared to other facial rejuvenation techniques. The sensation has been likened to a light pinch or the snap of a rubber band, but some people find it distressing.

Are there any side effects?

Side effects are minor and include:

Pain during treatment (reduced by contact cooling and if necessary, topical anaesthetic)
Skin turning pink and a little sore immediately after the procedure.
Sensation of a mild sunburn (redness, peeling, swelling) that may last a few days after treatment.
Rarely, skin pigment may absorb too much light energy and blistering can occur.
Sometimes the pigment cells (melanocytes) can be damaged leaving darker or paler patches of skin. White patches or scars are rarely permanent.
Hair loss may occur.
Bruising affects up to 10% of patients

Dangers Of IPL
References to peer reviewed studies of the dangerous and bystander effects of IPL to DNA and surrounding tissue with sources:

Effect of Intense Pulsed-Light Exposure on Lipid Peroxides and Thymine Dimers in Human Skin In VivoOlivier Sorg, PhD; Victor Janer, MD; Christophe Antille, MD; Pierre Carraux; Evelyne Leemans; Elizabeth Masgrau, MD; Jean-Hilaire Saurat, MD; Denis Salomon, MD

http://www.ncbi.nlm.nih.gov/pubmed/19587691 (page does not exist)" href="http://en.wikipedia.org/w/index.php?title=Source:_http://www.ncbi.nlm.nih.gov/pubmed/19587691&action=edit&redlink=1">J Invest Dermatol. 2010 Jan;130(1):86-92
Thermal injury causes DNA damage and lethality in unheated surrounding cells: active thermal bystander effect. Purschke M, Laubach HJ, Anderson RR, Manstein D.Wellman