Zinc PCA, also known as zinc pyrrolidone carboxylate or zinc L-pyrrolidone-5-carboxylate, is a coordination compound formed between zinc and pyrrolidone carboxylic acid. It is a white, free-flowing powder that is soluble in water and has a slightly acidic pH. Zinc PCA is used as an antidandruff agent in hair care products and as an astringent in skin care products. It is also used in some acne treatments and sunscreens.

Zinc PCA is a chelating agent, which means it can bind to metal ions and prevent them from reacting with other substances. This property makes it effective at removing excess oil, dirt, and other impurities from the skin and scalp. Zinc PCA also has antimicrobial and anti-inflammatory properties, which help to reduce the symptoms of dandruff and acne.

Zinc PCA is generally considered safe for use on the skin and scalp, but it can cause irritation in some people. If you experience any redness, itching, or burning, you should stop using the product and see a doctor.