"Of course, as I've aged, everything on my body hurts! My hips, back, shoulders—lots of aches and pains," she admits in the March issue of Women's Health, featuring the Being Mary Jane star on the cover.
And while she obviously keeps fit, Union hasn't done anything to alter what's naturally going on above the neck.
"I get asked all the time how I look so young," she says. "I don't like needles. I'm not going to rule out Botox, but the idea of putting a needle in my face—I'm not there yet."
So right now, her No. 1 tip for maintaining that youthful visage of hers is...
"My best anti-aging tip is the ability to say no, no, and hell no," Union insists. "We run ourselves ragged saying yes to every freaking thing, whether it's to our family, spouses or careers. I sleep eight hours a day and don't let myself stress out. A lot of people call it selfish, but I don't have any wrinkles."
No one can argue with that!
"I have pretty oily skin, I drink a lot of water, I don't smoke, and," she admits, "I don't have a hard life."
That being said, she is only human, and happily so.
"I dye my hair and people say 'You look young,' but my gray hairs are saying, 'She's old as f--k!'"
"I've learned to be kind to myself. I'm not obsessive about food, like 'Oh no, I ate badly, so I have to stay in the gym for two hours!'" the actress told Women's Health. "At the end of the day, did I enjoy that meal? Hell, yes! Am I going to stress out about it? Hell, no! and magically, the world doesn't end because of what I ate."
Read the entire interview in the March issue of Women's Health, on newsstands Tuesday.