Zinc PCA: what should you know about this ally for blemish‑prone skin?

Zinc PCA is a cosmetic active ingredient resulting from the combination of two compounds : zinc, a trace element naturally present in the body, and PCA (pyrrolidone carboxylic acid), an amino acid derivative also found in the skin under physiological conditions. More specifically, PCA is part of the natural moisturizing factor (NMF), a group of molecules involved in maintaining hydration of the stratum corneum.

From a chemical standpoint, zinc PCA corresponds to a salt formed between zinc and PCA, which makes it possible to combine these two entities within a single molecule. This form is particularly used in cosmetics, because it has good affinity with the skin and can be easily incorporated into different formulations (serums, lotions, creams), while remaining stable in aqueous solution.

Zinc PCA is an active ingredient obtained through a chemical synthesis process.

Zinc PCA is the result of a chemical reaction between pyrrolidone carboxylic acid and a zinc salt, most often zinc in the form of the oxide or sulfate. PCA itself comes from the cyclization of glutamic acid, an amino acid that is naturally present in the body and frequently obtained from plant-based resources, such as fermented sugar. During the reaction, the acidic group of PCA binds to the zinc ion to form a stable salt called zinc PCA. This form makes it possible to associate zinc with an organic molecule already recognized by the skin.

The resulting form of zinc is stable and well tolerated by the skin.

Zinc PCA is mainly used to support blemish‑prone skin. Several studies have demonstrated its effects on mechanisms involved in acne, particularly inflammation and bacterial proliferation. In a clinical study conducted on 16 volunteers with mild acne, a formulation containing 1% zinc PCA combined with derivatives of vitamins B3 and B6 was applied twice daily for six weeks. The results showed a 60% reduction in inflammatory lesions, as well as a decrease in the production of porphyrins, compounds associated with the activity of Cutibacterium acnes, a bacterium involved in the inflammation of acne lesions. Notably, this improvement was accompanied by good skin tolerance, with no impairment of the barrier function, which is often a challenge with anti-acne treatments.

Moreover, zinc PCA also appears to play a role in processes related to photoaging, a term that refers to accelerated skin aging caused by UV radiation. An in vitro study conducted on human dermal fibroblasts showed that zinc PCA was able to reduce the activation of certain UVA-induced transcription factors (AP-1), leading to a decrease in the production of MMP-1, an enzyme involved in the breakdown of collagen. At the same time, an increase in the expression of the vitamin C transporter (SVCT2) was observed, which resulted in a stimulation of type I collagen synthesis. These findings suggest that zinc PCA may help preserve the structure of the dermis.

Finally, zinc PCA more broadly helps protect the skin against oxidative stress. It acts as a cofactor for several antioxidant enzymes, particularly superoxide dismutase, which neutralizes reactive oxygen species before they damage membrane lipids, proteins, or DNA. Zinc PCA also helps stabilize cell membranes and limit lipid peroxidation, a process involved in the impairment of the skin barrier. At the same time, it contributes to the regulation of certain inflammatory pathways, notably by modulating the activation of transcription factors such as NF-κB. This helps reduce the production of pro-inflammatory mediators and, in turn, soothe skin irritation and redness.

The previously described properties of zinc PCA for the skin are also relevant at the scalp level. The scalp can likewise be affected by issues such as excessive sebum production, inflammation, or microbial overgrowth—processes on which zinc PCA can act.

In addition, more specifically, zinc PCA is often used as an adjuvant in anti-dandruff treatments. As a reminder, dandruff is often associated with excessive production of sebum combined with a dysbiosis of the scalp microbiota, particularly linked to the fungus Malassezia. In a clinical study conducted on 20 patients with moderate to severe seborrheic dermatitis , the use for four weeks of a gel containing zinc PCA, in combination with salicylic acid and piroctone olamine, followed by a lotion containing salicylic acid and piroctone olamine, led to a significant reduction in dandruff, itching, and erythema.

Another study confirms these promising results. Conducted in 30 patients, it evaluated a shampoo combining zinc PCA, piroctone olamine, and plant extracts including rosemary, chamomile, nettle, and mint. The results show a rapid disappearance of dandruff in some participants as early as two weeks, and a gradual improvement in the others within four weeks

However, in both of these studies, zinc PCA is systematically used in combination with other active ingredients known for their anti-dandruff efficacy, which makes it difficult to evaluate its specific contribution.

In another area, some data suggest a potential benefit of zinc PCA for combating hair loss. A clinical study conducted in 19 men with androgenetic alopecia evaluated the effectiveness of a topical solution containing caffeine, Procapil, and zinc PCA over a 12-week period. The results showed a 26.9% reduction in hair loss, as well as a visible improvement in hair density in about 68% of participants after twelve weeks.

Nevertheless, once again, zinc PCA is incorporated into a combined formulation, which makes it impossible to draw conclusions about its specific role in hair growth. However, these results suggest that when associated with certain active ingredients, zinc PCA could help improve the scalp environment and support hair growth.

Zinc PCA is an active ingredient that is generally well tolerated.

Several clinical trials available in the scientific literature have included it in formulations intended for blemish-prone skin or scalps prone to imbalance, without reporting any adverse reactions such as irritation or contact allergies. Unlike certain active ingredients used in the management of blemishes, such as retinoids or benzoyl peroxide, which are often associated with irritation, flaking, or dryness, zinc PCA does not present these drawbacks. PCA plays a key role here by helping maintain hydration of the stratum corneum, which makes it possible to counterbalance any potential drying effects of zinc alone.

In practice, zinc PCA can be used on all skin types, including the most sensitive ones, with no specific contraindications for topical application. It is also suitable for use during pregnancy, which makes it a versatile active ingredient that can be easily incorporated into a skincare routine.

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• SHARIFI-RAD J. & al. Preparation of strong antidandruff shampoo using medicinal plant extracts: A clinical trial and chronic dandruff treatment. Jundishapur Journal of Natural Pharmaceutical Products (2015).

• MAIA CAMPOS P. & al. Benefits of a dermocosmetic formulation with vitamins B3 and a B6 derivative combined with zinc-PCA for mild inflammatory acne and acne-prone skin. Biomedical and Biopharmaceutical Research (2018).

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• KALINOWSKA-LIS U. & al. Zinc(II) complexes with amino acids for potential use in dermatology: Synthesis, crystal structures, and antibacterial activity. Molecules (2020).

• FIROOZ A. & al. Assessment of the efficacy and tolerability of a topical formulation containing caffeine and Procapil 3% for improvement of male pattern hair loss. Journal of Cosmetic Dermatology (2023).

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