Elena Rubin had been working as a Wall Street analyst for several years before she admitted to herself that she was miserable. Not only did she sit in the bath and cry every night but her high-powered career had saddled her with autoimmune disorders and skin problems. After successfully seeking holistic treatment, she reassessed her life. "I came to the conclusion that all I wanted to do was spend time at the spa," she says. So I decided to open one. Thanks to New York State law, which requires that at least one owner of a spa have a cosmetology license, Rubin enrolled in beauty school, which she attended with the same sort of dedication she had given to her Harvard M.B.A. "The teachers really liked me," she says wryly. I never missed a class and I was all about critical thinking and scientifically backed facts. Now a sought-after facialist, Rubin has created an namesake skin care line that blends the rigor of the lab with the gentleness of natural ingredients. All her products are chirally correct, meaning they contain only the effective, nonirritating halves of molecules, making them safe for even the most sensitive complexions, and they have no artificial preservatives, colors or fragrances, and no sulfates. "My philosophy is to support the skin so that it can best perform its function," Rubin says. So instead of Retin A, which basically causes micro-injury to the skin to get it to produce collagen, I use beta-carotene, which is the precursor to vitamin A. It's like having a slice of citrus fruit every day instead of waiting until you're sick and then taking 10,000 milligrams vitamin C, which is, among other things, really going to upset your stomach. The star of Rubin's line is Stirling, a powerhouse antiaging serum that contains a potent blend of ultra-hydrating sodium hyaluronate, a synthetic version of the same lubricant found in the joints, and eight peptides: two to stimulate collagen production, two to help reduce the appearance of sun damage and four to tone and firm. "It's very effective while being very respectful of the skin," Rubin says. People love it - everyone comes back for another bottle. Elena Rubin Skincare Studio, 596 Broadway; (212) 537-5817; elenarubin.com.