We’ve all heard it said that confidence is sexy. And you see it in action all time time. Surely each of us has fallen under the spell of a certain someone who exuded an irresistibly confident air, or watched a friend work her magic at a bar and wondered what it is that makes her such a guy magnet.

“Attractiveness is not measured completely objectively,” writes Art Markman, Ph.D., YouBeauty’s Psychology Advisor. “We judge people’s physical attractiveness by many factors including their actual body type and facial structure, the way they carry themselves, the way they dress, the social energy they project and the way they engage with us. Most of these factors are completely under your control. Anyone can project her beauty to others. It all starts with confidence.”

Great. Unless you lack confidence in the first place.

“If you struggle with confidence, it’s more difficult to feel good about yourself in many ways, including seeing yourself as sexy,” says YouBeauty Self-Image Expert Heather Quinlan. “If you don’t see yourself as sexy, it’s unlikely that you’ll feel sexy and project that self-image to others.”

While we can get the flowing hair, the perfect pout, the alluring fashions that are the hallmarks of sexiness, the ultimate accessory can’t be bought. Fortunately, it can be faked.

“Carrying yourself confidently (standing up straight, eyes forward, smiling), looking people in the eye and speaking clearly can convey confidence, even if you don’t truly feel that way, and may actually help you feel more sincerely confident,” says Quinlan.

Markman contends that confidence is a self-fulfilling prophecy. Pretend that you’ve got it and you’ll start to believe you do. And believing in yourself is the crux of the matter. He says, “If you walk with confidence that you don’t feel, if you speak clearly when you want to whisper, if you look life in the eye when you want to look away, then the world will respond to your actions.” And so will you. In the same way that putting on a happy face can actually make you feel happier, striking a confident pose can make you feel more confident in a very real way. A 2010 study by Harvard and Columbia University researchers found that after assuming a dominant stance for just one minute, volunteers reported feeling more powerful and in charge. There was a physiological response as well: They saw a decrease in the stress hormone cortisol, and a surge of testosterone, the hormone most associated with dominance.

“Your external world is a manifestation of your internal world,” says orthopedic surgeon Ken Hansraj, M.D. “It is well known that when human beings and animals feel optimized internally they manifest power by presenting good posture. This study reveals that the reverse is true as well. Get into good postures and then you can control your internal neurochemistry and the way you feel. This internally-based confidence leads to better productivity, sense of well-being, state of physical being and finally sexuality.” In his book, “Keys to an Amazing Life: Secrets of the Cervical Spine,” Hansraj argues that good posture—ears aligned with shoulders, shoulder blades retracted—is directly related to finding emotional and physical love.

The confidence question doesn’t end there, though. Once you’ve made a connection, the feedback loop to feeling confident can help you engage more fully and with greater satisfaction than you may be naturally inclined to. “People who have a poor body image or feel uncomfortable in their own skin often say that they’re self-conscious with intimacy,” Quinlan reports. “They may feel embarrassed or awkward being naked in front of another person and have trouble focusing on anything other than unhappiness with their own body.”

Manhattan sex therapist Stephen Snyder, M.D., points out that unlike men, who are generally turned on by outside stimuli, women get turned on by the idea that they are irresistible. What he calls “self-related cues” are an integral part of a woman’s sexuality. “As any sex therapist will attest, for a woman to feel good about sex often requires that she like how she feels in her jeans,” he says.So should you fake it in the bedroom? That is, fake confidence? “Better to find something to delight you,” says Snyder, “such as a scent or an outfit that pleases you. Something you feel relaxed in.” And your partner can help you, too, he says, “by desiring you truly and honestly, and letting you know it.”

MORE: Test Your Confidence With the Self-Esteem Quiz