Tartaric acid is an acid found naturally in many plant species and the fruits they produce. Grapes are one of the best sources of this natural acid, although it's also found in significant quantities in cranberries, bananas, prickly pears and tamarinds. Tartaric acid, along with other weak acids like citric and malic acid, give wine its pleasantly tart taste. Tartaric acid also helps to lower the pH during wine fermentation. This prevents the growth of bacteria that could spoil the product. Because of its acidity, it's also a good preservative. Its tartaric acid that's responsible for the tiny crystals that form on the corks of wine bottles called 'wine diamonds'.
The benefits of tartaric acid extend beyond winemaking. This plant-based acid is used to make baking powder and cream of tartar, a powder that adds texture and volume to beaten egg whites, frostings, gelatin desserts and confectionary products. It's also used to flavor beverages and add tartness to foods. In addition, it can be used to tan leather and polish metal and is commonly used in the preparation of copper oxide.
Tartaric acid is well-known to the cosmetic and skin care industry. It's an ingredient in a variety of cosmetic and personal care products including facial moisturizers, skin toners, shampoos, hair conditioners, sun protection products and anti-aging treatments. In personal care products and cosmetics, it can be used to adjust the pH of the product so it isn't too acidic or basic.
Tartaric acid has other skin benefits as well. Along with lactic acid, glycolic acid, citric acid and malic acid, it's classified as an alpha hydroxy acid, a type of weak acid with exfoliating properties. Manufacturers of skin care products add alpha hydroxy acids to their moisturizing products because they hydrate skin. Alpha hydroxy acids also promote the shedding of dead skin cells on the surface of the skin. This gives skin a smoother appearance and more translucency with a gentle "glow" because a smoother skin surface reflects light better.
Alpha hydroxy acids, like tartaric acid, have an anti-aging effect because they stimulate collagen production in the dermal layer of the skin. Collagen is produced by cells called fibroblasts, and its production declines with age. This is one reason skin develops lines and wrinkles and loses its youthful firmness. Repeated sun exposure activates enzymes that speed up collagen breakdown, which is why it's so important to wear a sunscreen. Products that contain alpha hydroxy acids increase sun sensitivity, so wearing a sunscreen assumes even greater importance if you use products that contain tartaric acid or other alpha hydroxy acids.
Tartaric acid and other alpha hydroxy acids are ingredients in some acne treatment products. This is because they help to unclog pores, although another type of acid called beta hydroxy acids are more effective at doing this. Alpha hydroxy acids are water-soluble, whereas beta hydroxy acids are lipid-soluble, allowing them to better penetrate pores.
Alpha hydroxy acids also help to lighten darkly pigmented areas of skin due to sun spots or melasma, although they're most effective when used at higher concentrations. Some aestheticians and dermatologists do a series of alpha hydroxy acid peels to lighten pigmented areas, improve skin texture and soften the appearance of fine lines and wrinkles.
Is it safe? Tartaric acid is a naturally-occurring acid derived from plants, and it poses little risk to health in the quantities found in food products and cosmetics, although it's a muscle toxin at very high concentrations. The United States Food and Drug Administration classifies it as "generally recognized as safe' as a food additive, although it can have a laxative-like effect in some people.
In cosmetic products, the Environmental Working Group's Skin Deep Cosmetic Database deems it to be a low-hazard cosmetic ingredient. Despite its lack of toxicity, it's irritating to the eyes. It can also cause mild skin irritation. Some people report mild skin redness, itching and flaking when they first start using it. This usually becomes less pronounced over time. Allergic reactions to tartaric acid are uncommon. Although tartaric acid is classified as an alpha hydroxy acid, it's not as commonly used in skin care products as glycolic and lactic acids because it's not as stable.