ABC News' Elisabeth Leamy and Vanessa Weber report:

When it comes to eyebrows, thin is no longer in. People still love Brooke Shields' gorgeous eyebrows. And Kim Kardashian's dark, dramatic brows have almost developed a cult following.

But if you've been waxing and plucking for years, you may find that your eyebrow hair just won't grow back.

Some people with that problem are turning to eyebrow transplants.

For 10 years, Pamela Penrose watched as bald spots appeared in her eyebrows. She was constantly filling them in with a pencil hoping for a better look.

"It's a little embarrassing and it affects my self-esteem," Penrose told "Good Morning America," adding that she envied Shields' sophisticated look.

Penrose turned to Dr. Sanusi Umar for an eyebrow transplant. Doctors used to transplant head hairs, but Umar pioneered a way to harvest hair from a woman's arms, legs or nape of the neck.

Hair from those areas "much more resembles the natural eyebrow," Umar, of Derm Hair Clinic in Los Angeles and Redondo Beach, Calif., told "GMA."

"It's slow to grow, small in appearance and much more resembles the natural eyebrow," he said.

It's painstaking work. Each hair is transplanted individually, and the entire procedure lasts about 2½ hours.

"GMA" went back to visit Penrose three weeks after she had the transplant.

"My eyebrows look a lot larger and thicker and exactly what I wanted," she said, adding: "I feel like a totally different person. I feel much more confident."

Shannon Morrison once had thin, sparse brows, but after her transplant the outline of her brows appeared thicker.

Sarah Tirosh was so frustrated by her brows that she resorted to painful tattooing to get a dramatic brow.

"Now my face looks even and normal," Tirosh said. "I am absolutely happy, 100 percent," Tirosh said.

Eyebrow implants are not cheap. They cost between $6,000 and $8,000, depending on how much hair needs to be replaced.

But there is another alternative that women can consider first: Rogaine.

Rogaine is the anti-balding medication used mostly by men, but there is a women's version. Dr. Doris Day, a dermatologist, said her patients have had good luck getting eyebrow hair to grow in fuller using it.

A word of caution: Be careful how you apply it. If you get the treatment on other parts of your face, you could end up growing unwanted hair there.