What a Peel Does
The acid loosens the bonds between dead cells at the surface and helps them shed. The lower the pH and the longer the contact, the deeper the process reaches and the greater the strain.
The result is a smoother surface, more even tone and better penetration of whatever is applied afterwards. Those three effects are real and are achieved reliably with a well-chosen protocol.
The mechanism is the same as with home acids, described in our article on AHA acids. The salon difference is concentration, pH and above all control over timing.
Glycolic, Lactic, Mandelic
Glycolic acid has the smallest molecule and penetrates fastest. It gives the most pronounced result on uneven texture and post-acne marks, but is also the most likely to provoke a reaction when misjudged.
Lactic acid has a larger molecule, acts more gently and hydrates at the same time, which suits dry and mature skin. It is also the sensible choice for a first peel when tolerance is unknown.
Mandelic acid has the largest molecule and is the gentlest. It is the preferred option on sensitive skin and on deeper phototypes, where harsher exfoliation carries a higher risk of subsequent pigmentation.
Salicylic Acid and Oily Skin
Salicylic acid is oil-soluble and therefore enters pores, whereas AHAs work mainly on the surface. That makes it better suited to congestion and blemish-prone skin.
It also has a calming action, which is an advantage on inflamed skin. The limitation is known and worth checking before treatment: it is not used where there is salicylate sensitivity.
pH, and Why Concentration Alone Means Nothing
Acids work in an acidic environment. A high-concentration product at a near-neutral pH will act considerably more weakly than a lower concentration at the right pH.
So comparing products by the percentage on the box alone is misleading. The two parameters are read together, and with professional formulas the manufacturer usually declares both.
Assessment Before the Procedure
Ask about retinol, acids and new products in the past two weeks, about recent procedures, sun exposure and any upcoming holiday. Each of these can call for postponement or a gentler protocol.
Phototype matters in the choice: on deeper skin the risk of subsequent hyperpigmentation is higher, which shifts the selection toward gentler acids and shorter contact.
With a suspected skin condition, an active infection or prescribed treatment, the procedure is not performed and the client is referred to a dermatologist. That is not caution but the boundary of cosmetic work.
What Goes On After the Peel
Soothing and restorative ingredients, not actives. Panthenol, centella, ceramides and plain moisturising. Skin at this point lets more through and tolerates less.
The temptation to add a strong active while penetration is easier is exactly the mistake that produces a reaction over the following days. The full aftercare regime is in our article on post-procedure care.
Sun Protection Decides Whether It Was Worth It
Skin after a peel is considerably more prone to pigmentation. Without daily protection the result does not merely fade, it can reverse: work on tone ends in a new mark.
So a peel before a beach holiday is a poor idea, however conveniently it fits the schedule. It is more sensible to plan a course for the months with weaker sun.
A Course, Not a Single Treatment
A series of gentler peels at suitable intervals gives a more predictable result than one harsher intervention, at considerably lower risk. That holds especially on sensitive skin and deeper phototypes.
Time is left between treatments for full recovery. Shortening the intervals does not speed the result up; it accumulates strain and often leads to a state worse than the starting point.
What to Promise and What Not To
You can promise smoother skin, more even tone and faster fading of post-blemish marks. Those changes are visible and reliably achievable over a consistent course.
You cannot promise scar removal, a change in deep lines or a lasting result without maintenance. A peel works on the surface, and the result is maintained rather than fixed once and for all.
Preparing Skin Before a Course
Skin prepared for a few weeks before the first peel tolerates the procedure considerably better. Preparation usually means a stable home routine with moisturising and barrier support, not introducing new actives.
The reverse also holds: a client who has used aggressive products right up to the appointment arrives with a depleted barrier. In that case postponing is the better decision, not simply lowering the concentration.
When working on pigmentation, preparation often includes tone-targeting ingredients started weeks beforehand. That is part of the protocol rather than an upsell.
Contact Time and Neutralising
Time is the parameter with the greatest practical weight and the only one the specialist controls in the moment. It is tracked by the clock rather than by eye, and recorded afterwards along with the skin response.
Observation during the procedure is part of the work. Even, mild redness is expected; blanching of areas, strong burning or an uneven response is a signal to stop immediately.
The neutralising product is kept ready rather than looked for at the moment it is needed. That sounds obvious and is among the things skipped when the schedule is tight.
Peels for Pigmentation
Pigmentation is the indication where peels give the best results and at the same time carry the highest risk. Too aggressive an intervention can provoke exactly the response you are trying to reduce.
So the approach is a series of gentle treatments plus consistent photoprotection rather than one strong intervention. The mechanism behind pigment change is covered in our article on sun damage.
Peels for Blemish-Prone Skin
With congestion and blemish-prone skin an oil-soluble acid generally does better than an AHA, because it reaches inside the pore. Combined protocols also work but demand more careful judgement.
With active inflamed lesions the procedure is postponed. A peel on inflamed skin raises the risk of post-inflammatory pigmentation, which lingers considerably longer than the blemish itself.
Home Care Between Treatments
Weeks pass between appointments, and the home routine decides whether the result accumulates or is lost. Actives return gradually and one at a time, not all at once on the day skin happens to look good.
Written instructions work better than spoken ones. Clients forget details by the evening, and it is the details that determine whether a reaction appears before the next appointment.
In Short
Choose the acid for the skin and phototype, read concentration together with pH, track time by the clock, and plan a course rather than a single treatment.
And be precise about the limits. A peel works on the surface, the result is maintained, and sun protection is the condition without which the whole exercise loses its point.
Season and Scheduling a Course
The months with weaker sun suit intensive work better, because the risk of subsequent pigmentation is lower and the client keeps to the protection regime more easily. That is a practical rather than a formal recommendation.
In summer a course is not necessarily stopped, but it moves to gentler acids and shorter contact. The compromise is in intensity rather than consistency, because an interrupted course starts over.
Documenting the Protocol
Record the acid, concentration, pH, contact time and skin response at every appointment. With a good result that allows exact repetition, and with a reaction it allows the cause to be identified rather than guessed.
The record is also what separates a protocol from improvisation. Clients sense the difference even when they cannot name it, and it shows in whether they come back.
When a Peel Is Not the Right Choice
With a compromised barrier, active irritation, or a client not prepared to use sunscreen daily. In the last case the procedure will probably do more harm than good.
Having that conversation is part of the professional job. Better the client leaves with a preparation plan than with a treatment whose result will reverse after two weeks in the sun.