Rumour: “Laser thins the skin” — What does the science say?

Short answer: in general, no. There is no evidence that laser performed with a suitable device, at the correct settings and at appropriate intervals causes long-term thinning of healthy skin. A hair removal laser targets the hair follicle. Tissue studies carried out with skin resurfacing lasers have shown an increase in collagen production and an orderly healing response. The redness and sensitivity during the healing period are temporary and are not thinning. The real risks are burns, discolouration and scarring; these increase with incorrect or excessively frequent treatment.

Where does the rumour come from?

There are understandable reasons for this rumour. In the days after laser and peels the skin turns red, feels tight, becomes dry, may peel and is more sensitive to touch, to the sun and to cosmetic products. A person going through this may think that their skin has 'become thin'. The second reason is the real damage seen after incorrect treatments: burns, pigmentation and scarring. The third is a confusion: strong corticosteroid creams are known to be able to thin the skin when used for a long time, and over time this knowledge has been attached to other skin treatments as well.

There is also a problem of language. In everyday speech, 'thin skin' mostly describes skin that reddens easily, has visible blood vessels or is quickly irritated. In medicine, however, thinning of the skin means a measurable decrease in the thickness of the layers of the skin. These two are not the same thing.

Is laser a single procedure?

No. Lasers are distinguished from one another by which structure in the skin absorbs the light. To assess the rumour, you need to know which laser is being talked about.

Does laser hair removal thin the skin?

The light used in laser hair removal is absorbed by the dark pigment in the hair follicle, and the heat produced acts on the follicle. The aim of the procedure is not to peel or remove layers of skin. For this reason, laser hair removal performed at the correct settings is not expected to thin the skin; nor is thinning of the skin listed among the side effects in the reviews on the subject or in the patient information from dermatology organisations.

The fact that some people perceive their skin as 'thinner' or smoother after hair removal mostly has to do with the reduction in hair and in bumps at the base of the hairs. The redness, mild swelling and sensitivity seen within one to three days after the procedure, meanwhile, are temporary. The real risks lie elsewhere: unsuitable settings or tanned skin can lead to burns, blistering, discolouration and, rarely, scarring. The details are in our article “Laser Hair Removal: How It Works, Who It Suits and What to Watch For”; another common worry is covered in our article “Rumour: Laser hair removal causes cancer — What does the science say?”.

What have tissue studies shown for fractional and non-ablative lasers?

These lasers create column-shaped zones of heat damage in the skin that are too small to be seen with the naked eye, and preserve the intact skin between them. In one study examining what this method does in the skin, a single session was given to the forearm of twelve volunteers, and tissue samples taken over three months were examined. The continuity of the upper layer of the skin was restored within one day, the upper layer was completely renewed in seven days, findings pointing to an increase in collagen production were detected on the seventh day, and at the end of three months no scar tissue was found in the lower layer. The researchers interpreted this as a wound-healing response initiated in the lower layer of the skin.

These findings need to be read with restraint. The studies are small, were mostly carried out on forearm skin and with a single session, their follow-up is limited to months, and they reflect particular device settings. There are no large studies measuring the effect of many sessions over years on skin thickness. The available data point not to thinning but to repair and new collagen production; however, this does not mean that treatment at any setting and any frequency is harmless. The details of the method are in our article “Fractional Laser: How Suitable Is It for Acne Scars, Wrinkles and Skin Texture?”.

If ablative laser removes the upper layer of the skin, is that not thinning?

This is where the rumour comes closest to the truth. Ablative lasers do indeed remove the upper layer of the skin and part of the lower layer in a controlled way. However, this is not a loss that does not come back: the upper layer re-forms from cells coming from the hair follicles and the surrounding intact skin, while a repair process begins in the lower layer.

In a study of 28 adults in whom carbon dioxide laser was applied to sun-damaged forearm skin, measures of new collagen production rose to several times the baseline level about three weeks after the procedure and remained high for at least six months. The researchers described these changes as an orderly wound-healing response resulting in marked structural change in the lower layer of the skin. In other words, what is expected once healing is complete is not thinner skin but remodelled skin.

The price of this is recovery time and risk. Recovery after ablative lasers can take around two weeks, and there is a small but significant risk of complications; this is also why gentler methods were developed. If healing does not go smoothly, if infection develops or if the treatment is carried out more deeply than necessary, a scar may be left. A depressed scar does mean that the skin in that area has truly become thinner; this is not the usual outcome of laser but a complication.

Is the sensitivity during the healing period thinning?

No. In the days and weeks after laser the skin repairs itself. During this period the protective surface of the skin has not yet fully returned to its former state; the skin loses water more easily, reddens more quickly and is more sensitive to the sun. This is mostly what a person is describing when they say 'my skin has become thin'.

• Redness, tightness, dryness and peeling are expected findings of the healing period and last days to weeks, depending on the intensity of the procedure.
• Products you used before without any problem may sting and burn during this period; do not go back to products containing acids and retinoids until your physician recommends it.
• During this period the sun increases the risk of pigmentation. Sun protection is one of the most important parts of healing.
• Picking off crusts and rubbing the skin increase the risk of scarring.
• If the redness lasts longer than expected or increases, or is accompanied by pain, discharge and blistering, see your physician.

The fact that this sensitivity is temporary does not mean that it is unimportant; care during the healing period directly affects the result. The general principles are explained in our article “Aftercare Following Medical Aesthetic Procedures: General Principles and Warning Signs”.

So what are the real risks?

It is not that laser has no risk; it is just that the risk is not where the rumour says it is. A recent review of the unwanted effects of laser and energy-based devices states that the problems are associated with unsuitable choice of device, incorrect settings, inadequate patient assessment and the practitioner's inexperience, and that discolouration, scarring and eye injury can be seen in the late period. Dermatology organisations also warn that burns, irreversible discolouration and scars can be seen in treatments carried out by inexperienced people.

• Burns and blistering: mostly associated with settings unsuited to the skin type or with treating tanned skin.
• Darkening or lightening of the skin: the risk is higher in darker skin and in those who go out in the sun after the procedure; some of it may not resolve on its own.
• Scarring: can develop after a deep burn, infection or treatment that is more intensive than necessary.
• Excessively frequent treatment: new sessions carried out before the skin has completed its healing do not allow the time needed for repair and can increase the risk of irritation, prolonged redness and pigmentation. Your physician sets the interval between sessions.
• Unauthorised treatment: treatments carried out without an examination, outside a healthcare facility or by people without adequate training markedly increase the risk.

The signs of these problems, their prevention and what to do are explained in detail in our article “Burns and Pigmentation Changes after Laser and IPL: Darkening, Lightening and Scarring — Prevention and What to Do”; the precautions specific to darker skin are in our article “Laser, IPL and Chemical Peels on Olive and Darker Skin: Pigmentation Risk, Choice of Device and Safety Precautions”. For situations in which a scar develops, see our article “Scars and Keloids”.

Does a chemical peel thin the skin?

The same rumour circulates about peels, and the answer is similar. A chemical peel creates controlled damage in the upper layers of the skin; a new layer replaces the one that peels off. According to a recent review examining tissue changes after peels, with superficial peels the upper layer is renewed and the changes in the lower layer are unclear; with medium-depth peels, mostly an increase in the thickness of the lower layer and in the amount of collagen has been reported, and with deep peels long-lasting thickening and collagen production in the upper and lower layers. The review also notes that the studies are small and differ from one another.

Here too the real risk is not thinning; it is unsuitable depth, treatment by non-physicians, the use of high-concentration acids at home and the sun during the healing period. The details are in our article “Chemical Peels: What They Are, Who They Suit and What Recovery Involves”. We address similar questions about skin resurfacing with needles in our article “Microneedling”.

Conclusion

The rumour that laser thins the skin is a generalisation from the temporary sensitivity of the healing period and from the real damage seen after incorrect treatments. A hair removal laser targets the hair follicle; tissue studies of skin resurfacing lasers, limited though they are, point not to thinning but to repair and collagen production. What needs attention is the risk of burns, pigmentation and scarring; these risks can be reduced, but not brought to zero, by correct patient assessment, a suitable device and settings, an adequate interval between sessions and sun protection.