Many say menthol rub can fix cough, but others still skeptical

Q: You have written that putting Vicks VapoRub on the soles of the feet can stop a nighttime cough. That’s pure fluff or maybe written as an ad for Vicks. You haven’t bothered to provide any scientific information to support this claim.

A: You are right that there have been no randomized controlled trials of putting Vicks VapoRub on the soles of the feet. Given the distinctive aroma of Vicks, we can’t imagine how you would find an appropriate placebo to conduct such a study.

You are not the only one to dismiss this home remedy. But we have received hundreds of testimonials from people who have found it helpful.

How might it work?

One study published in the journal Drugs in Context (Oct. 11, 2023) identified the transient receptor potential channel TRPV4 as contributing to acute cough associated with rhinovirus infection. The scientists confirmed that certain ingredients (specifically menthol, camphor and eucalyptus oil found in Vicks) activate TRPV4 as well as TRPV1 and TRPM8. They suggest that this activation could help reduce cough symptoms.

So, what’s a TRP channel and what are they doing on the feet? These channels modulate the passage of ions into cells, and they are found throughout the digestive tract as well as in the skin (Pharmaceuticals, Dec. 14, 2016). Nerves in the skin that detect temperature have generous supplies of TRP channels.

Most over-the-counter cough and cold remedies contain the oral decongestant phenylephrine, which the Food and Drug Administration recently said is ineffective. Questions have also been raised about the safety and effectiveness of dextromethorphan, or DM, the ingredient in most over-the-counter cough suppressants (Journal of Pharmacy and Pharmacology, September 2000).

We take no money from drug companies to promote their products. This is not an “ad” for Vicks.

Q: I am on Synthroid for hypothyroidism. About a year ago, my doctor lowered the dosage. After six months on the lower dose, my hair started falling out. My hairdresser even found a few areas with no hair! To counteract this, I started using a shampoo containing biotin. I am sure that the biotin has helped me regrow my hair. A: Levothyroxine (Synthroid) is the primary treatment for hypothyroidism, a condition in which the thyroid gland produces too little of this essential hormone. When thyroid levels are too low, people frequently experience hair loss (Medicine, Jan. 5, 2024). Sudden hair loss of the type you describe is called telogen effluvium.

Unfortunately, the remedy you have chosen may pose a problem.

Biotin from shampoo can be absorbed through the skin (Journal of Nutrition Science and Vitaminology, June 1999). Biotin can also interfere with thyroid tests, lowering TSH and raising T4 and T3 levels falsely (Annals of Clinical and Laboratory Science, January 2023). As a result, your doctor might conclude that your thyroid dose is working better than it really is — leading to more hair loss. If you stop using biotin several days before your next blood test, you should get accurate test results.

Q: I have had yellow, crumbly toenails for years and assumed it was nail fungus. Nothing worked.

After reading about Neosporin, I tried my overthe-counter three-antibiotic cream. What amazing results! I had major improvement fast. I apply three times a week before bed and put on socks to protect the sheets. A: Thanks for sharing your story. Some “nail fungus” actually may be bacterial. That could explain why a number of cases respond to antibiotic ointment.

In their column, Joe and Teresa Graedon answer letters from readers. Send questions to them via www. peoplespharmacy.com.

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