People’s Pharmacy: Listerine stopped scalp flakes

Q. In one article, you suggested that Listerine might be helpful for scalp psoriasis/eczema. I have had flaking with red plaques for several years, so that article intrigued me.

After one week of use, the flaking stopped. It’s been three weeks now, and I am still free of flakes. Before this, the back of my shirt would usually be covered with flakes that my wife constantly had to brush off. She says the plaques on my scalp look less red.

The article suggested resolution after six months of use. Until now, I have tried everything except steroids, to no avail. I find this result interesting. It might be a placebo response. To find out, I will follow up as objectively as possible.

A. A long time ago, the maker of Listerine advertised its product for “infectious dandruff.” Then dermatologists dismissed the idea that dandruff or seborrheic dermatitis could be caused by a pathogen. The Food and Drug Administration frowned upon advertising a mouthwash for flaky scalp.

More recently, though, research has identified an imbalance of microbes on the skin as contributing to itchy, flaky scalp problems (Biophysics Reviews, March 13, 2023). Alterations in the distribution of fungi also play a role in eczema (Journal of Fungi, Oct. 31, 2022).

Because the ingredients in Listerine (thymol, eucalyptol, menthol, methyl salicylate) discourage the growth of fungi and other potential pathogens, applying this amber mouthwash to the scalp may be helpful.

You are not the only one to note some benefit. Another reader wrote, “I suffered from scalp psoriasis for many years. My aunt told me to use amber Listerine after I shampooed my hair. I haven’t had a scalp psoriasis outbreak since!”

We wish we could provide evidence from clinical trials, but a search of the medical literature didn’t reveal any. Please let us know how you are doing in six months, as other readers will be interested.

Q. I read recently that treating hypothyroidism with levothyroxine has been linked to osteoporosis, even if the dose is just right. Years ago, I switched from Synthroid to Armour Thyroid. How does Armour compare to levothyroxine with regard to osteoporosis?

A. Physicians have known for decades that too much thyroid hormone can increase the risk of osteoporosis. They assumed, however, that if the dose of levothyroxine was in the sweet spot and thyroid levels were normal, there would not be a problem.

The Baltimore Longitudinal Study of Aging revealed a different story. Older people taking levothyroxine lost bone mass even if their thyroid levels were normal. As far as we can tell, no one has studied desiccated thyroid extract (Armour) to find out if it has a different effect.

You can learn more about the treatment of both hypo- and hyperthyroidism in our “eGuide to Thyroid Hormones.” This online resource can be found under the Health eGuides tab at www.PeoplesPharmacy.com.

People who have had thyroid disease should have their bone density monitored. If there is evidence of bone loss, strength training might be helpful. One reader shared her experience: “I have been on Synthroid for over 40 years. My doctor has always checked my bone density along with my Vitamin D and calcium and all have been great. At 71 years old, my last bone density test showed no bone loss. My job required heavy lifting and walking. I wonder if this helped keep my bones strong.”

Email Joe and Teresa Graedon via their website: www.PeoplesPharmacy.com.