Combination protocols exist for a reason. Higher TCA concentrations on their own carry more scarring risk than the same depth achieved in two steps.
The visible signal during a medium peel is frosting: the skin turns white as proteins in the epidermis and upper dermis coagulate. The practitioner reads the frost, its uniformity, colour and speed of onset, to judge depth in real time.
That reading is a skill, and it is the reason the same bottle in two different hands produces two different peels. The sensation is a strong burn that subsides over minutes, sometimes helped with a fan or cooling.
Afterwards, the skin darkens and tightens over two or three days, then peels in sheets over roughly a week. Redness follows the peeling and fades over several weeks.
Most people take five to ten days away from anything that requires looking presentable. Sun avoidance is strict for weeks, and the new skin pigments readily if it is caught out.
A medium peel can improve fine lines, moderate sun damage, actinic keratoses, pigment that has resisted lighter treatment, and superficial scarring. It is a noticeable change for the right skin.
Risks include post-inflammatory hyperpigmentation, especially in deeper skin tones, prolonged redness, and infection. Cold sores around the mouth can reactivate, for which antiviral cover is routine, and scarring follows if the peel goes deeper than intended.
Medium peels are medical procedures. They are performed by physicians or by nurses and physician assistants under physician supervision.
Deep peels
Deep peels reach the mid-dermis. The agent is phenol, almost always combined with croton oil in formulas whose proportions have been refined over decades to control depth.
This is not a stronger version of the peels above. It is a different procedure, and it is performed in a different setting.
Phenol is absorbed through the skin and can affect heart rhythm. A full-face deep peel is therefore done with intravenous fluids and cardiac monitoring, in segments, with pauses between them, and sedation or anaesthesia is typical.
The skin is often dressed or taped afterwards. The first week or two involve wound care of the kind that follows a burn: oozing, crusting, ointment, and no possibility of appearing in public.
Redness lasts weeks to months. Permanent lightening of the treated skin is common enough that deep peels are largely reserved for lighter skin, and the line between treated and untreated skin has to be planned for.
What a deep peel can do is dramatic by the standards of this category: deeply etched lines around the mouth and eyes, heavy photodamage, and precancerous change across large areas. The result lasts years.
It is a serious undertaking with a serious recovery. It belongs with a physician who does it regularly and can describe the monitoring and the complications without consulting notes.
What "depth" is in practice
The categories above suggest three neat bands. In practice depth is a continuous variable.
The same acid at the same concentration reaches different depths depending on how the skin was prepared, how many coats were applied, and how long each sat before neutralising. Pressure and the thickness and oiliness of the skin change it again.
A "superficial" TCA peel applied in several layers by an enthusiastic hand becomes a medium peel. That is one reason the category on the price list matters less than the training of the person holding the gauze.
Preparation also changes depth. Several weeks of a retinoid beforehand thins the stratum corneum and evens penetration, and a period of a lightening agent reduces pigment risk in skin that darkens easily.
A careful clinic will talk about preparation before it talks about the peel. A careless one will book the peel for the same afternoon.
Recovering in Los Angeles
The city's contribution to peel recovery is ultraviolet light, twelve months a year, and a culture that does not encourage staying indoors. After any peel deeper than the most superficial, the new skin needs shade, a mineral sunscreen, and patience.
Readers regularly ask where to spend the peeling days without either hiding at home or standing in sun. Indoors and dim is the honest answer.
Cabrillo's aquarium in San Pedro is small, cool and rarely crowded on a weekday. It is the standing recommendation for the South Bay.
Downtown has its own options for a face that should not see noon. Lobbies and interiors beat streets, and the evening beats the afternoon.
The Conservancy's walking tours move between buildings and lobbies more than streets. Bring a hat for the crossings.
Evening is the right time of day for a freshly peeled face, and the city has more to offer after dark than most people use during a recovery week. Plan the calendar around that.
A performance at the Music Center downtown makes a reasonable evening. The light is low and the seats face away from the windows.
For readers who want a garden rather than a building, the choice should still be about canopy. Coastal options are open and bright, and the marine layer burns off by the time most people arrive.
The shaded oak walks at Descanso Gardens in La Cañada are gentler than any coastal option, with the standing caveat of a wide hat. Go before ten.
Dry Santa Ana days deserve their own mention. Low humidity makes peeling skin crack rather than flake, and a bland occlusive ointment matters more in that week than in a humid one.
Questions worth asking
Which acid, at what concentration, and why for my skin? A specific answer is the minimum.
How deep is this peel intended to go, and how will you judge depth while it is on? The word "frost" should appear in the answer to a medium peel.
What preparation do you want me to do first, and for how long? None is a poor answer for anything beyond a light glycolic.
What will my skin look like on day three, and when will I be presentable? A day-by-day account is a sign of experience.
What is your plan if I pigment afterwards? The question separates practitioners who have treated a range of skin tones from those who have not.
In brief
A superficial peel polishes. A medium peel resurfaces. A deep peel rebuilds, at a cost measured in weeks and with a physician and a monitor in the room.
Each is a different tool for a different problem. The practitioner's judgement about which acid, how strong, how many layers and how prepared is the whole of the value.
Choose the judgement, and the peel will follow.
