What is photorejuvenation?

IPL (intensepulsed light, intense pulsed light) is currently the most widely used optical equipment. Since the relevant sales supervision of IPL has not been standardized, IPL is currently widely used in many non-medical beauty institutions other than hospitals. Therefore, it is very important to use IPL correctly to make it exert its application effect and reduce side effects.

The IPL is the most useful device if used correctly.

The therapeutic value of IPL is very high. For many indications, IPL can easily achieve the same efficacy as laser equipment, but only if it is used correctly. The so-called correct use, including IPL pulse number, pulse width, filter, cooling and patient selection and other aspects.

IPL is not a laser, but an incoherent, non-monochromatic light emitted by a flash lamp, but the therapeutic value of IPL is not inferior to that of a laser.

IPL technology started in the mid-1990s when the industry knew very little about it. As technology continues to evolve, today’s IPL spectrum has been extended to 500nm –
Any band in the 1200nm range, and its target tissue (skin chromophore) comprehensively includes water, melanin and heme. That said, IPL can treat multiple indications simultaneously. But the key is to adjust the treatment parameters according to the target tissue, otherwise the effect will be minimal.


The band of the IPL depends on the system and handpiece or filter used. There are two types of filters: short-pass cut-off and long-pass cut-on.

Short-pass cut-off filters are the most commonly used, and can filter all wavelengths except a specific wavelength. For example, a 560nm filter has a pass spectrum of 560nm – 1200nm.

The long-pass cut-off filter filters out all wavelengths except a specific band. For example, a 1064nm filter has a pass spectrum of 1064nm – 1066nm (not a laser).

The selection of the appropriate filter is an important factor in ensuring the success of the treatment and should be determined based on the indication and the skin tone of the patient.

Since the absorption peak of melanin is located in the lower wavelength range, higher wavelengths have a protective effect on dark skin.

Higher wavelength filters penetrate better in hair removal treatments (reaching dividing cells is the key to permanent hair removal); while lower wavelength filters are more easily absorbed by melanin and are therefore safer for light skin.

skin type

The darker the lesion, the easier it is to remove (instantly use longer wavelengths). For light-colored lesions, it is necessary to choose shorter wavelengths that are more easily absorbed by the pigment, and the lower wavelength limit depends on the patient’s skin type.

In addition to wavelength, the adjustable parameters of IPL include optical fluence and pulse width.

Countless pulse trains can be generated by adjusting the number of pulses, pulse width and delay between pulses. It is precisely because of this feature that IPL is highly dependent on patients. That is, the operator must select appropriate parameters according to the patient’s condition.

Pulse Width

Pulse width refers to the duration of each pulse, and the pulse width of IPL is in milliseconds. For darker skin types, longer pulse widths can better protect the epidermis (with the same light radiation intensity, the peak heat is lower, thus avoiding permanent damage to melanocytes); Large vascular lesions. On the other hand, shorter pulse widths are more suitable for treating pigmented skin lesions.

It is worth noting that since melanosomes are extremely small and the thermal relaxation time is short, the ideal pulse width should be as close as possible to the thermal relaxation time.

For telangiectasia, short pulse width has better curative effect. When treating vascular skin lesions, since it needs to act on the deep layers of the skin, it is necessary to increase the intensity of light radiation as much as possible while controlling the peak heat (lower than the epidermal burn point).

cool down

The skin cooling mechanism varies from device to device. Some use contact and some use air cooling. Proper cooling expands the therapeutic possibilities and the functionality of the device.

When treating sub-epidermal lesions, more epidermal cooling is required; when lesions (eg, sunburn) are located in the epidermis, less cooling is required.

In most cases, cooling parameters require operator control. There are also devices that offer automatic cooling control.

The cooling head will become hot after cooling. Therefore, it should be ensured that the cooling head itself has enough time to cool down, otherwise it will affect the cooling effect of the skin and cause side reactions.


The clinical indications for IPL are extremely broad, and photoaging symptoms (pigmentation, telangiectasia, and wrinkles) are traditionally used.

At the same time, IPL can be used to treat: rosacea, acne, chloasma, port-wine stain, hemangioma, alopecia, angiokeratoma with vasodilatation, hypertrophic scar, skin heterochromia, pigmented purpura.

In addition, IPL can also be used for photodynamic (PDT) treatment of actinic keratosis.


Two separate studies have shown no interaction between the use of IPL after filler injection.

In addition, there are also studies showing that no adverse reactions have been seen in the use of IPL after botulinum toxin injection.