TCA and medium-depth peels

What it is

TCA is an acid that coagulates the proteins of the skin, and its strength sets how deep it goes (PMID 34504524, PMID 31333972). A medium-depth peel reaches the papillary dermis, the thin upper layer of the dermis, or the top of the reticular dermis beneath it (PMID 31333972, PMID 1576794). As the skin heals, a new band of collagen forms under the surface, thicker after deeper peels (PMID 7180716), and type I collagen rises in the treated skin (PMID 7868719).

Its place among skin treatments follows from that depth. Medium peels carry less risk than deep phenol peels because they stop in the upper dermis, and for the same reason they do less for deep scars and wrinkles (PMID 1576794). For a facelift patient, they treat what the lift does not: fine wrinkles and uneven color (PMID 34183633).

Where it came from

• In 1982 Stegman compared TCA, phenol and dermabrasion under the microscope and showed that each wound heals with a new layer of upper dermis (PMID 7180716).
• In 1986 Brody combined solid carbon dioxide with TCA to make a peel between a light TCA peel and a deep phenol peel (PMID 3782600), and in 1989 his serial biopsies showed that extra coats of TCA deepen the wound (PMID 2506259).
• In 1989 Monheit introduced the Jessner's plus TCA peel for sun-damaged skin, precancerous spots and wrinkles (PMID 2778184); Jessner's solution strips oil and part of the outer skin so 35% TCA penetrates evenly (PMID 7600705). Glycolic acid was tested as an alternative first coat and gave a similar depth (PMID 8874526).
• In 1994 Dingman showed that a 35% TCA peel can be done at the same operation as a deep-plane facelift (PMID 8278488).
• In 1999 Obagi standardized the Blue Peel, with measured coats and a color guide to set the depth (PMID 10594578).
• In 2025 Raef, Brody, Monheit and Coleman reviewed the advances since then, led by the International Peeling Society (PMID 40827745).

Who it suits

• Sun-damaged skin with fine lines, brown spots and rough precancerous spots (PMID 2778184, PMID 34504524).
• Facelift patients who also want better skin texture and color (PMID 34183633, PMID 19730318).
• Melasma in darker skin. TCA and Jessner's peels improved melasma more than hydroquinone cream, and glycolic acid peels did better still in pooled trials (PMID 32947652); a modified Jessner's plus 20% TCA also worked (PMID 33625140).
• Acne scars. High-strength TCA pressed into single scars (the CROSS method) helped most patients with darker skin types (PMID 12460296).
• Darker skin. Peels carry a higher risk of pigment change and abnormal scarring in skin of color (PMID 24098904, PMID 35189253); one surgeon's technique is designed for light and dark skin alike (PMID 28097306).
• Deep wrinkles respond better to a laser or a deep peel: around the eyes, a CO2 laser improved lines more than Jessner's plus TCA (PMID 9256910, PMID 1576794).

How it is done

• The skin is cleaned and degreased, a first agent (Jessner's solution, glycolic acid or solid CO2) is applied, and 35% TCA follows (PMID 7600705, PMID 8874526, PMID 3782600). The first coat lets a moderate TCA strength reach the needed depth, which limits scarring (PMID 31333972).
• Reading the depth. TCA turns the skin white (frost) as it acts (PMID 9513236). Obagi's visible and touch signs of depth matched the depth found on biopsy, including the difference between the upper and the deeper dermis (PMID 8659944). More coats go deeper (PMID 2506259), and the Blue Peel uses set volumes per area with a color guide that shows even coverage (PMID 10594578).
• Eyelids. TCA on eyelid skin reached no deeper than the papillary dermis at the strengths tested (PMID 9513236).
• Scars. The CROSS method applies very strong TCA only inside each acne scar (PMID 12460296).
• Combinations. Botulinum toxin given before the peel improved crow's feet more than the peel alone in a randomized trial (PMID 28491999). Fractional radiofrequency followed by TCA improved skin more than either alone (PMID 30908361), and microneedling with TCA improved melasma more than TCA alone (PMID 36533799).
• Preparing the skin. Tretinoin cream before and after a 40% TCA peel made the frost form faster and more evenly but added no measurable benefit to the result in one trial (PMID 8601654).

Results and how long they last

• Sun damage. Low TCA strengths suit light sun damage, and higher strengths or combinations reduce wrinkles (PMID 34504524). A 40% TCA peel improved brown spots, precancerous spots and texture most, and wrinkles least (PMID 8601654). A series of 35% TCA peels reduced wrinkles more than a weaker TCA with glycolic acid, which gave better hydration and lighter pigment (PMID 31603267).
• Fine lines. Jessner's plus 35% TCA treated light to moderate lines in a plastic surgery practice, after a learning curve (PMID 19730318).
• Lines around the eyes. A CO2 laser smoothed them more, and its redness lasted longer (PMID 9256910).
• Precancerous spots. One peel matched three weeks of fluorouracil cream at clearing visible spots, and most patients preferred the single peel (PMID 7857114). Pooled studies found the cream cleared spots completely more often (PMID 32745330), and photodynamic therapy cleared more than TCA in a randomized trial (PMID 28012181).
• Collagen. New collagen formed in light and dark skin (PMID 7868719, PMID 14756647). In an animal model collagen rose for weeks and returned to baseline by 2 months, while the dermis stayed thicker (PMID 11176627).
• Durability is not well measured: most studies follow patients for 6 to 12 months (PMID 9256910, PMID 7857114). After a combined lift and resurfacing, the complexion kept improving through the first year (PMID 9858190).

Risks and how surgeons lower them

• Depth is the main lever. Deeper peels give more improvement and more complications (PMID 30550830); using a first coat so that a moderate TCA strength reaches the target is how surgeons keep the depth controlled (PMID 31333972).
• Dark patches. Persistent hyperpigmentation followed about 1 in 17 peels in a large series of light and dark skin; light patches, thread veins and infections were rare (PMID 28097306). Skin of color carries the higher pigment risk (PMID 24098904).
• Fungal infection. About 1 in 13 peels in one plastic surgery practice (PMID 19730318).
• Scarring. In a randomized trial of 35% TCA for precancerous spots on the face and scalp, about 1 in 5 patients scarred on the TCA side (PMID 28012181). TCA mixed with croton oil behaves unpredictably and has caused severe raised scars (PMID 42664735).
• Eyelids. Deep eyelid peels and phenol have pulled the lower lid outward (ectropion); the TCA strengths tested on eyelid skin stayed shallow (PMID 9513236).

Recovery

• New skin forms in 7 to 10 days (PMID 10594578).
• Redness after Jessner's plus TCA around the eyes lasted about 2 and a half months, against about 4 and a half after a CO2 laser (PMID 9256910).
• In the precancerous-spot trial, one patient had redness for 3 months and no other side effects were seen (PMID 7857114).
• A series of five TCA sessions caused no side effects that needed treatment (PMID 31603267).
• After a facelift combined with resurfacing, patients went through one recovery of 6 to 8 weeks (PMID 9858190).

With a facelift

• Surgeons once separated peeling and facelifting in time for fear of losing the lifted skin. Dingman tested peeling agents on pig skin flaps, found 35% TCA safe on thick flaps, and then combined a modified deep-plane facelift with an immediate peel without complications from the combination (PMID 8278488).
• On lifted (undermined) skin in front of the ear, TCA up to 40% produced a predictable burn without killing the full thickness of the skin; phenol-croton oil peels should not be used on undermined skin (PMID 28732800).
• Lifts combined with a TCA peel or a short-pulse CO2 laser caused no full-thickness flap loss and no lasting pigment problems (PMID 9858190), and full-face Jessner's plus TCA with face and neck lifts caused no thick scars (PMID 19730318).
• In the PAVE lift, which combines SMAS plication, fat grafting and peels, temporary dark patches followed about 1 in 25 TCA peels (PMID 27320171).
• A review places medium TCA and deep phenol peels as the tools for the fine wrinkles and uneven color a facelift leaves (PMID 34183633).

Questions to ask a surgeon

• Which first coat and which TCA strength will you use, and how deep will the peel go? (PMID 31333972)
• How will you judge the depth during the peel? (PMID 8659944)
• What is my risk of dark or light patches with my skin type, and how will you lower it? (PMID 24098904)
• Will you peel the skin you lift during my facelift, and at what strength? (PMID 28732800)
• How long will the redness last? (PMID 9256910)
• For precancerous spots, would a cream or photodynamic therapy clear them better? (PMID 32745330)

Open questions

• The evidence base is small: few prospective studies (PMID 34504524), and the precancerous-spot studies carry a high risk of bias (PMID 32745330).
• Skin preparation: tretinoin added no measurable benefit in one trial (PMID 8601654), and the systematic review calls for standard preparation in future studies (PMID 34504524).
• Device combinations: radiofrequency before TCA (PMID 30908361) and microneedling with TCA (PMID 36533799).
• Darker skin: a large series reports low complication rates (PMID 28097306), while reviews stress the higher pigment risk (PMID 24098904, PMID 35189253).
• TCA with croton oil has been compared with phenol-croton formulas (PMID 35863466), and severe scarring has been reported (PMID 42664735).
• Peeling research is now coordinated by the International Peeling Society (PMID 40827745).

Terms

• Trichloroacetic acid (TCA): peeling acid that coagulates skin proteins; strength sets depth (PMID 34504524, PMID 31333972).
• Medium-depth peel: wound through the epidermis into the papillary or upper reticular dermis (PMID 31333972, PMID 1576794).
• Jessner's solution: acid solution applied before TCA to remove part of the epidermis so TCA penetrates deeper (PMID 31333972).
• Frost: white surface change as TCA coagulates skin; used as an endpoint (PMID 9513236, PMID 10594578).
• Papillary and reticular dermis: the thin upper and thick lower layers of the dermis (PMID 8659944).
• Grenz zone: band of new tissue under the epidermis after a peel (PMID 8874526).
• Blue Peel: TCA applied in measured coats with a color guide to a set depth (PMID 10594578).
• CROSS: high-strength TCA pressed into single acne scars (PMID 12460296).
• Actinic keratosis: rough precancerous sun spot (PMID 7857114).
• MASI: melasma area and severity index (PMID 33625140).
• Glogau scale: photoaging grade used to select patients (PMID 31603267).

Papers