Balding men who seek to look better or younger by undergoing hair transplants are on the right course, a small new study suggests.

People shown before-and-after pictures of hair transplant recipients rated men with more locks as looking more attractive and younger, researchers found. People also thought the men looked more successful and approachable after the procedure.

"It was satisfying to us," said senior author Dr. Lisa Ishii, of Johns Hopkins School of Medicine in Baltimore. "I definitely don't want to be doing a procedure on people that doesn't make a difference."

Hair transplant procedures vary by doctor, Ishii told Reuters Health. Generally, individual hairs are taken from the back of the head to fill out areas of the scalp with hair loss.

"We've been doing these procedures for years and everyone assumes it does something for your appearance, but we never measured that," she said.

The lack of data on how much hair transplants may improve a person's image was bothersome to Ishii, because patients would ask for specific estimates.

In an attempt to get objective opinions on men's appearances before and after the procedure, she and her colleagues asked 122 volunteers - 58 men and 64 women - to view 13 pairs of images. Seven pairs showed men before and after having had a hair transplant; the other six pairs were of men who didn't have a hair transplant or any other significant cosmetic procedures between the two photographs.

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The participants were asked to rate each image on age, attractiveness, successfulness and approachability.

The reviewers thought the men who'd had hair transplants looked about four years younger in their "after" photos. They also thought the men looked more attractive, successful and approachable after their procedures.

"It showed there were measurable improvements on measures that are meaningful to the patients," she said.

Armed with the data, Ishii said it's easier to answer her patients' questions.

"I find I'm able to make much more scientific and objective conversation with them with regard to what their expectations should be," she said.

It shouldn't be surprising that having hair is tied to professional accomplishment and trustworthiness, wrote Dr. Jeffrey Epstein of the University of Miami and the Foundation for Hair Restoration, in an editorial published with the study in JAMA Facial and Plastic Surgery.

Still, he wrote, "Crowd theory is clearly limited in establishing the level of attractiveness for an individual, for all that really matters is how one person (the patient) - not a crowd - views one's attractiveness in terms of personal satisfaction."

Ishii cautioned that the results are based on a small number of participants, but there are plans to conduct the experiment again among a larger number of people.