Martha Stewart, 85, says the secret to looking twenty is discipline, not injectables. "It's not just about shooting up 10 peptides every day," she told Harper's Bazaar in a new interview. "Staying older and well is a chore. It takes a lot of work and a lot of attention."

Stewart launched her skincare brand, ELM Biosciences, last year with dermatologist Dhaval Bhanusali. "I started a skincare line because I really wanted stuff that would be appropriate, easy to use, and efficacious all at the same time," she said. A year after launch, the brand has entered color cosmetics with the Elemental Lip Serum, available in shades from clear to a barely-there pink — Stewart's personal go-to.

The lip product is strategic. "It's the first time that we've had a real longevity play on a product, because the attention on longevity is vast," Stewart said. "Every single magazine is focusing on it; all doctors are focusing on it; all their patients want to know how to stay vibrant and live longer."

Her recent "nudes" Instagram post, she confirmed, was promotion for the new serum. Her selfie method is unglamorous and precise: hold the camera right, keep the light on your face — "not off to the side or above or below your head. Nothing's more unattractive than that." She checks the mirror while shooting, takes three or four frames, deletes three or four, and keeps one.

Stewart claims no holy-grail product. "I'm much more adventurous than that," she said. She once cleansed with baby oil. Now she is testing emollient cleansers for ELM and uses the brand's serum and night cream every evening. "I never just stay with the product just because I've used it forever."

Her routine is fixed on maintenance. She never sleeps in makeup. She washes and blow-dries her hair at least three times a week — "I couldn't bear to go any longer than that." She gets a manicure and pedicure at least once a week. "It's kind of tedious, but it's essential to me."

The body is the next frontier for the brand. Stewart is testing an ELM body lotion and says she has found the right formula. "As we get older, we realize that we have to focus on not only our face but our body," she said. She has given the lotion to her masseur and her physical therapist and uses it exclusively.

On the lips, she is her own best case study. Lips show aging early because they move constantly — talking, laughing, smiling. What makes her laugh? "I enjoy good comedy, a silly joke. I love watching my grandchildren misbehave. I love my animals. I love to laugh at them and with them."

Growing older has surprised her in no way. "You start getting older the minute you're born, and you have to learn how to deal with it all," she said. "It's about posture, appearance, good grooming, and dressing appropriately."

Even her wisdom flows both directions now. Her daughter Alexis recently advised her: "Don't wear two-piece velour workout suits. Mix it up." Stewart's verdict on the advice: "La-di-da."

What keeps her vibrant? Two things: "Exercise, of course, but also good work."

With a color-cosmetics entry, a body lotion in testing and a new cleanser in development, ELM Biosciences is positioning itself squarely inside the longevity conversation Stewart says every magazine and doctor is already having.