Photodynamic therapy requires three components: a photosensitizer; a light source; and oxygen. Photosensitizers are topically applied solutions that cause certain types of abnormal cells to produce light-absorbing molecules called porphyrins. This change allows the light treatment to target the abnormal cells. After applying a topical photosensitizer, a medical light source is focused on the skin to activate it. This light source may provide blue light, red light, or intense pulsed light (IPL). A doctor will decide what light source is best for the individual. Combined with the photosensitizer and the presence of oxygen, the light helps to destroy pre-cancer cells, acne cells and bacteria. PDT also reduces the size and activity of the oil-producing glands on the skin, known as the sebaceous glands.

The skin is swabbed to remove oils. Aminolevulinic acid is then applied to the skin and left on for 60 minutes. The patient then rests in a reclining position with goggles on while a blue light shines on the skin for 16 minutes. In some patients, Intense Pulsed Light (IPL) may be used instead of the blue light to help with brown spots and blood vessels. A titanium/zinc sunscreen is then applied.

The number of treatments required depends on the person's skin type, the number of lesions they have, and how severe those lesions are. Anywhere between two and five sessions are necessary, at 2-4 week intervals, for optimal results. Some people may notice results after a single session.

Current recommendations suggest 1 to 2 treatments are necessary to achieve results.  Recent data suggests approximately 90% of patients obtain significant improvement from this regimen.  In addition, precancerous lesions and sometimes very superficial skin cancers that are not yet visible on the skin can be cleared.  Improvement likely lasts years with the continued use of sunscreens and anti-aging creams such as retinoids.

PDT tends to be more effective for inflammatory, rather than non-inflammatory, acne. Another important benefit of photodynamic therapy is that it does not involve the use of antibiotics or oral retinoids, such as Accutane. This makes PDT a viable treatment for people who cannot take those medications. PDT may be especially beneficial for people with severe acne or those whose acne has not responded well to other treatments.

Photodynamic therapy (PDT) is the use of a medication activated by light. PDT for treating precancerous lesions (actinic keratoses), improving skin tone and erasing sun damage utilizes a topical (on the skin) solution in conjunction with a blue light, or intense pulsed light source. This treatment acts by eliminating sun damaged and precancerous cells as well as shrinking sebaceous glands damaged by the sun.

Prior to treatment, the skin will be cleansed and treated with microdermabrasion or a scrub. The photosensitizing agent is then applied to the skin. Some people may experience a stinging sensation during this portion of the treatment, which should gradually subside. Next, a medical light source is shone on the skin for 8-20 minutes. The light activates the photosensitizing agent. At this stage of the procedure, some people may experience a stinging or burning sensation, the intensity of which varies. After treatment, the skin is extremely sensitive. People must stay indoors, out of sunlight, for 48 hours following treatment. This is because the photosensitizing agent makes skin sensitive to sunlight, so there is a risk of severe burns from sun exposure.