What it is and How it Works
Sodium (Na) is a chemical element, which in its raw form is a soft, silvery-white, highly reactive metal. It is a member of the alkali metals and exists in a number of minerals including feldspar, sodalite and rock salt. Sodium is an important electrolyte and an essential ion needed for blood regulation. It also aids in heart and nervous system performance.
This very versatile element occurs in more than 80 forms. In skin care, some of the most commonly used sodium compounds include sodium ascorbyl phosphate, sodium hyaluronate, sodium bicarbonate, sodium chloride, sodium lactate, sodium PCA, and sodium silicate. This, incidentally, is a short list.
While these all provide wonderful benefits for the skin, there are a few particularly worthy of the spotlight. One of which is sodium hyaluronate (hyaluronic acid). It is a major component of skin and is an integral part of tissue repair. It helps to plump, lubricate, moisturize, and prevent transepidermal water loss.
It also increases collagen synthesis and normal skin function, and is critical to the structural integrity of the dermal collagen matrix. Since it is such an amazing hydrator, it increases the penetration of other vital actives. Hyaluronic is also commonly used as soft-tissue filler.
Another noteworthy ingredient is sodium ascrobyl phosphate. This vitamin C derivative promotes collagen synthesis, brightens and lightens skin tone, and delivers a potent dose of antioxidants to the skin.
Sodium lactate, which is derived from lactic acid, not only moisturizes, but also works to rejuvenate aging skin, provide exfoliation, regulate pH and lighten skin. Finally, Sodium PCA, derived from amino acids, is extremely valuable in providing hydration. This high-performance humectant helps keep skin soft and supple.

Where to Find it
Sodium is found in a variety of food sources, but most commonly as a food additive either in the form of table salt or baking soda.
In cosmeceuticals, sodium compounds such as sodium chloride and sodium bicarbonate are commonly found in cleansers and scrubs, as they have antiseptic qualities and provide a mechanical cleanse and exfoliation.
Sodium ascorbyl phosphate may be found in brightening and hydrating topicals, and should always be used in combination with a good sunscreen. Sodium hyaluronate and sodium PCA are typically found in skin hydrating and nourishing formulas or combined with other active ingredients in topicals geared towards rejuvenating the skin and stimulating collagen production.
Though sodium plays an important role in maintaining healthy skin and overall body health, too much in our diet may have negative effects including dehydration and hypertension. There are also certain sodium compounds such as sodium laurel sulfate, which has been linked to skin irritation and degenerative effects on cell membranes, to be cognizant of. With the proper knowledge however, many sodium preparations can reap tremendous rewards for the skin.