When you’re swooning over your new love interest, wearing a perma-grin as cartoon-like hearts float all around you, you positively glow. There’s a reason: Love looks good on you.When you’re falling madly in love, your brain releases dopamine as well as other chemicals that give you energy and focus, explains Helen Fisher, Ph.D., a biological anthropologist at Rutgers University and author of five books on love.QUIZ: What’s Your Relationship Style?“Your energy skyrockets, you’re curious, optimistic, motivated and focused,” she says. “And this affects your entire body language: you smile, swish your hair, stand taller and your voice goes up—all of this makes you more attractive.”But it’s not just romance that boosts your looks in a heartbeat. According to Gloria Brame, Ph.D., a Georgia-based sexologist and author of “The Truth about Sex,” having sex, or rather, having an orgasm, will do more for your complexion than any product you’ll find on Sephora’s shelves. “It’s the ultimate fountain of youth,” says Brame. “Sex significantly reduces stress, which we know is bad for the skin, and also increases blood flow, much like a workout—with the added beauty benefits of the sex chemicals your body releases.”MORE: Eight Ways Sex Makes You BeautifulSo whether you’re simply love struck or regularly knocking boots, it shows its pretty face in various ways:Bright eyes Thanks to the energy surge that adrenaline gives you—along with that can’t-eat-can’t-sleep-can’t-think-of-anything-else feeling–falling in love makes you look alert and bright-eyed, explains Fisher. It also sends a subtle cue to the object of your affection: When you’re interested in someone, your pupils dilate, which in turn sparks their interest. In fact, several studies have shown that both men and women are more attracted to photographs of the opposite sex that have been digitally retouched so that the pupils appear larger.Fake it: While we wouldn’t recommend swiping your optometrist’s pupil-dilating eye drops, curling your lashes and lining the inside of your lower lid with a pale pink eyeliner has the eye-popping benefits of a triple espresso. Try Benefit Eye Bright, $20.Rosy cheeks Anyone who’s ever had a crush knows that just seeing the person who takes your breath away can be enough to make you blush. As your body pumps out adrenaline (which is why your heart feels like it’s beating out of your chest), your circulation increases and your cheeks get a healthy flush. According to Brame, having sex also does the trick. Much like a workout, sex increases blood flow to give cheeks a rosy glow.Fake it: Sweep an iridescent powder blush over the apples of your cheeks. The looks-good-on-everyone (and appropriately-named) classic: Nars Blush in Orgasm, $27.Smooth, glowing skin Can sex really take years off your face? Absolutely, says Brame. Getting busy increases circulation to help flush out toxins and bring oxygen to the skin for that heavenly glow. Plus, when you climax your body releases estrogen, which helps boost collagen production to help ward off wrinkles. “That’s why it’s so important to maintain a healthy sex life during and after menopause, when you’re losing estrogen,” she says. In a 10-year study at Royal Edinburgh Hospital in Scotland, 3,500 participants who looked exceptionally young for their age (an average of seven to 12 years younger than they actually were) were interviewed about their lifestyle. The researchers concluded that an active sex life was the second most significant factor in how young a person looked, right after regular exercise.Fake it: For a radiant complexion, start by polishing away dulling dead skin cells with an enzyme scrub. We love Jurlique Fruit Enzyme Exfoliator, $45. Go for a foundation that contains light-reflecting particles for a luminous complexion. Try L’Oreal Paris Visible Lift Smooth Absolute, $16.95.QUIZ: How do you feel about your face?Fuller lips. When you’re in love, it turns out you have something in common with Angelina Jolie (sadly, it’s not Brad Pitt). Having sex may give you lustrous lips–literally making them appear larger. “Some say it’s the extra oxygen, while others think it’s a surge of estrogen,” notes Brame. “Your lips become puffier and also deepen in color [during sex].”Fake it: For a deep, making-out-for-hours kiss of color, go for a lip stain like Revlon Colorstay Just Bitten Lipstain + Balm, $8.99. If it’s bee-stung lips you’re after, try a classic lip plumper like DuWop Lip Venom, $16.