Chemical peels in London

Depth, and what determines it

Peels are classified by how far the agent takes effect. Superficial peels affect the epidermis. Medium peels reach the upper dermis. Deep peels go further, and are effectively a surgical-grade procedure with anaesthesia, monitoring and weeks of recovery.

Depth is not simply a function of which acid is in the bottle. It is determined by the agent, its concentration, its pH, how it is applied, how long it is left on, and how the skin was prepared. The same acid at the same strength behaves differently on skin that has been primed with a retinoid for six weeks and on skin that has not.

The decision being made is how much damage to do, deliberately, with the intention that it heals better than it was.

Choosing the acid

Glycolic acid

The smallest alpha hydroxy acid, so it penetrates readily. General resurfacing, brightening and textural refinement.

Lactic acid

Larger, gentler and more hydrating. A sensible choice in dry or sensitive skin.

Mandelic acid

Larger still, so it penetrates slowly and evenly. Often preferred in darker skin types and in rosacea-prone skin for that reason.

Salicylic acid

Oil soluble, so it works inside the follicle. The usual choice for congested and acne-prone skin.

Trichloroacetic acid

Used for medium depth work, alone or in combination, and for focal treatment of ice pick scars.

Combination peels exist for good reasons and are not automatically better. What matters is whether the agent was chosen against your skin and your finding.

Skin type is the safety question

The Fitzpatrick scale describes how skin responds to ultraviolet light. It is crude and it remains the practical starting point, because the higher the type, the greater the risk that inflammation leaves a brown mark that outlasts the problem being treated.

Post-inflammatory hyperpigmentation is the complication that turns a peel into a longer problem than the one you arrived with. It is largely preventable: appropriate agent, conservative depth, priming over several weeks, and absolute sun protection afterwards.

Melasma deserves separate mention. It responds to some peels and it relapses readily, and it can be aggravated by heat as well as by light. A peel plan for melasma should be cautious, topical-led and long term. See pigmentation.

Preparation and the appointment

Skin is usually primed for two to six weeks beforehand, commonly with a retinoid, a pigment-inhibiting agent where relevant, and daily sun protection. This is not an upsell. Priming makes the peel more even and reduces complications.

You should be asked about:

• Recent isotretinoin, recent laser, recent waxing in the area.
• A history of cold sores, since medium depth peels can trigger an outbreak.
• A tendency to keloid or hypertrophic scarring.
• Pregnancy and breastfeeding, which restrict some agents.
• Active skin infection or broken skin in the area.
• Recent sun exposure or sunbed use, which is a reason to postpone.

During treatment expect stinging and warmth that build and then subside. Superficial peels are usually comfortable. Medium peels are not, and that should be stated plainly beforehand.

Recovery

After a superficial peel: tightness and mild redness for a day, then light flaking for two to four days. After a medium peel: noticeable redness, darkening of the treated skin, then sheets of peeling from around day three to seven, resolving over roughly ten days.

• Do not pick or pull peeling skin. This is the single commonest cause of scarring and pigmentation after a peel.
• Use only the products you have been given or told to use.
• Avoid exercise, sauna and heat for the first two to three days.
• Avoid all sun exposure and use broad-spectrum protection daily, including near windows.
• No waxing, threading, facials or abrasive products for two weeks.

Risks

• Post-inflammatory hyperpigmentation, especially in Fitzpatrick types four to six.
• Prolonged redness or irritation.
• Infection, including reactivation of herpes simplex.
• Scarring, uncommon with superficial peels and a genuine risk with deeper work or with picking.
• Uneven result where application was uneven or the skin was not primed.
• Loss of pigment, rare, more likely with deeper peels, and sometimes permanent.

A practitioner who cannot describe how they would manage each of these is a practitioner to decline.

Who performs peels, and the boundary that matters

Peels sit across the boundary between beauty therapy and medical practice. Superficial peels are widely and legitimately performed by qualified aesthetic therapists. Medium depth work belongs with a medically qualified practitioner who can prescribe and manage complications.

Ask which depth is proposed, what specific training the person has for that depth, what the follow-up is, and what happens if the result is uneven. In London, many premises offering these treatments require a local authority licence, which addresses the premises rather than the clinical judgement. See choosing a skin clinic.