A hair growth medicine that comes in a pill? Yes, according to this CT doctor.

Sometimes a solution will be right in front of you and you’ll miss seeing it. It can even happen to physicians.

Minoxidil, with the brand name Rogaine, has been sold as a topical treatment to reverse baldness since 1988, at first only by prescription, after starting out as a blood pressure medication.

As a prescription treatment for high blood pressure, minoxidil has been given as a pill. But what Dr. Brett King, an associate professor of dermatology at the Yale School of Medicine, found was that, given at low doses, oral minoxidil grows hair better than the kind that comes as a liquid or foam.

“This drug that has been around for literally 40 years for the treatment of high blood pressure, it works well for the treatment of male-pattern and female-pattern hair loss,” King said.

Oral minoxidil is a prescription medication. It’s best to see a dermatologist specializing in hair loss, King said.

The male- and female-pattern hair loss King referred to is androgenic alopecia, and is pretty common. “By the time men turn 80 years old, 80 percent or more of men have male-pattern hair loss,” he said.

Androgenic alopecia is recognized by balding at the crown of the head and a receding hairline in men. In women, it is marked by a thinning of the hair, especially on the top of the head, a more diffuse type of hair loss, King said.

Rogaine’s website says up to 90% of men and 80% of women will see results after three to four months of continuous use, but it must be applied continually to the scalp. It works by reviving hair follicles, partly by increasing blood to the area, the website states. Rogaine is owned by Johnson & Johnson.

Being able to reverse the process is important for many people, said King. “Hair speaks to somewhere in the recesses of our consciousness,” he said. “It says youth, vitality. … It conveys something very important about us.”

He said finding a treatment for male-pattern baldness is especially important for young men who begin to lose their hair before the normal middle age.

King said minoxidil will work on androgenic alopecia, but there are other types of alopecia as well, such as alopecia areata, which afflicts actor Jada Pinkett Smith. She has shaved her head and it was a Chris Rock joke about her baldness that led her husband, Will Smith, to slap Rock at the Academy Awards in March.

“I’m trying to get through to everybody: These are all different forms of hair loss,” King said. In June, the Food and Drug Administration approved the first treatment for alopecia areata, called Olumiant.

“Alopecia is just a wastebasket term for anybody with hair loss, but it doesn’t tell you anything about why they have hair loss,” King said.

Studies using 20 to 100 mg of oral minoxidil showed it worked for high blood pressure but there were serious side effects in some patients, so it was given a black box warning.

A 2011 study in the British Pharmaceutical Journal said that while researchers were studying minoxidil for high blood pressure they noticed it helped grow hair. In 1971, the FDA gave the drug an emergency use authorization, but only for two weeks of treatment, because of side effects, the paper states. Because it was successful, doctors began using it for more than two weeks, and that’s when the hair growth was noticed.

As reports got out that 60 to 80% of trial volunteers saw hair growth, “Upjohn’s headquarters in Kalamazoo, Michigan, was inundated with volunteers for hair loss trials,” the paper states. “But dermatologists were dubious that minoxidil could stimulate hair follicles to produce not just fine ‘vellus’ hairs, but coarser, pigmented ‘terminal’ hairs, from the atrophied follicles on bald scalps.”

Meanwhile, King said, “nobody’s been paying attention to the fact that it is a very high dose. Why not try a low dose? I’ve been given oral minoxidil to my patients. I started using it in 2015.”

Since then, “you’re finding more and more reports, more and more evidence in the reputable dermatological literature showing oral minoxidil between 0.5 and 5 mg a day are often effective for the treatment of male-pattern hair loss and female-pattern hair loss,” King said.

King said hair growth in other parts of the body besides the scalp and men’s faces “can happen but it’s relatively uncommon. For most people, it’s not enough to be a concern. For a few, it is.”

“This medicine has been available for 40 years and for the first 40 years nobody in dermatology was touching it,” he said. “The magic in this story [is] it’s like medical anthropology.”

Ed Stannard can be reached at estannard@courant.com or 860-993-8190.