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Colorless Iodine for Nail Fungus

Applying colorless iodine to ugly nails may help clear the infection. Be careful not to use too much, so you don't absorb excess iodine.

Toenail fungus is unsightly but harmless for most people. Occasionally, an infected nail responds by warping so that it becomes difficult to get a shoe on the foot. While there are prescription treatments for nail fungus, many are pricey and some can cause scary side effects. As a result, many people prefer to use home remedies against their ugly toenail fungus. We have written frequently about hydrogen peroxide, Vicks VapoRub, Listerine or vinegar soaks. Some readers insist that they prefer to use colorless iodine on their nails.

Does Colorless Iodine Fight Nail Fungus?

Q. Do you know about a cure for toenail fungus using decolorized iodine every day? I put it on my nails when I get out of the shower, working the stylus around and under the toenails.

It takes a year to get rid of fungus because that’s how long it takes for a toenail to grow out. One has to be diligent and use it every day. I continue to do this even after the fungus is gone. The iodine keeps the area dry and prevents a recurrence.

A. Many readers share your enthusiasm for colorless iodine against nail fungus. Because iodine has both anti-fungal and anti-bacterial activity, it would explain why it might be helpful against nasty nails.

One caution, however. Excess iodine absorption through the skin might lead to iodine toxicity. Symptoms include nausea, diarrhea and a burning sensation in the mouth. Hyperthyroidism could be another complication.

Why Not Use Clear Instead of Brown Iodine?

Q. I was interested in the letter from a reader who applied tincture of iodine to his nails to fight fungus. He mentioned that it stains the nails brown. I am surprised you did not tell him that iodine also comes as a colorless liquid. My mother used it for years to control toenail fungus.

A. Many other readers hastened to tell us that we should have mentioned clear iodine. It is also called decolorized or “white” iodine (yodo blanco in Spanish) and won’t stain the skin the way brown tincture of iodine does. It should be available in most drugstores, though you may have to ask the pharmacist to help you find it. Iodine is a good disinfectant and also has antifungal activity. Consequently, it may help against bacterial as well as fungal infections.

Finding Colorless Iodine to Treat Nail Fungus:

Some readers report difficulty in finding this product. Here’s one such complaint:

Q. I have been trying to find white (no dye) iodine. No pharmacy near me carries it. In the past I used it successfully to get rid of wart-like growths. I have also heard that it works against nail fungus. Any ideas where I should look?

A. Iodine has been used as a disinfectant and anti-fungal agent for more than a century. Standard tincture of iodine can stain the skin brown, which is why people use “white” iodine. Humco makes iodides tincture (decolorized iodine). Your pharmacy can order it or you may find it at Humco.com.

A few other readers have made suggestions:

“I am surprised that you did not give the correct chemical name for white/clear iodine. It might make it easier to find. It is simply a water solution of potassium iodide. In addition to being anti-fungal it is also used as an expectorant.”

Don’t call it white iodine:

“I think that some of you are using the wrong word about white iodine. Try asking for DECOLORIZED IODINE. I found some in the CVS pharmacy. If you can’t find it then ask your pharmacist to order, using the word “DECOLORIZED IODINE” instead of “WHITE IODINE.” Paint your toenail several times a day.”

Another reader offers this success story:

“I had toenail fungus. My doctor prescribed Lamisil, but after reading about the side effects I did not want to take it, even though my insurance would have covered the THOUSANDS of dollars in cost! After reading your article, I went online and ordered decolorized iodine which came in small bottles. I could only get like a package of 6. It was about $30 and I figured it was worth a try.

“I used it once a day for a month, at bedtime after washing my feet. I swabbed it carefully all over the toenail and all around the cuticle and skin surrounding the toenail, including the tip of my toe. I only had a problem on the big toes but applied the iodine to all toes just in case it was starting where I could not see.

“Two months later now, there is plainly new growth that is healthy and the old discolored part is plainly growing off. About half my nail is new, clean and strong, while the part that is growing off is discolored and thin and weak. There is a very obvious line where the old nail is growing off. I’m very happy with the results.”

Can Iodine on Nails Be Absorbed?

Q. In a recent article, a person said that having a scan with iodine led to signs of hyperthyroidism. A thyroid doctor found antithyroid antibodies in the patient’s blood. You replied that some people react to iodine exposure by developing thyroid problems.

I have been considering using decolorized (white) iodine on my fingernails, which are weak and brittle. Painting iodine on nails every day for a week and then weekly after that is supposed to strengthen the nails.

Now I wonder if that is safe. Although my thyroid levels have always been normal, there are thyroid problems in my family (sibling, aunts and uncles are on Synthroid).

Using Decolorized Iodine to Fight Nail Fungus:

A. We have heard from a number of readers that decolorized iodine can be helpful against nail fungus. It does have antifungal activity. We do not know whether it could strengthen nails that are simply brittle but not infected. Occasionally, brittle nails signal an underactive thyroid gland, though. Consequently, if you have other symptoms (fatigue, constipation, dry skin, mental fogginess, hair loss), you should see your doctor.

It is unlikely that putting iodine on your nails will affect your thyroid gland. When povidone iodine is used as a disinfectant, the skin absorbs it and urinary excretion increases significantly (Thyroid, June 2005). This returns to normal within three to five days.

So far as we can tell, no one has measured iodine absorption through finger- or toenails. However, nails do not absorb minerals very well. As a result, these surfaces seem less likely to absorb large quantities of the mineral than skin. We would be very surprised if putting white iodine on nails led to enough iodine absorption to make a difference for thyroid function.

Even dietary iodine through multivitamin pills does not appear to increase the chance of thyroid cancer or other thyroid problems (Cancer Epidemiology, Biomarkers & Prevention, Sep. 2001). On the other hand, the dose of iodine used in contrast material during a medical scan is huge, more than 30 times the minimum daily allowance for this mineral (JAMA Otolaryngology-Head & Neck Surgery, May, 2013).

Learn More:

To learn more about keeping nails healthy and fighting nail fungus, you may wish to read our free Guide to Hair and Nail Care. It can be found in the Health eGuides section. There, you will also find our eGuide to Thyroid Hormones, an online resource with a wealth of information on thyroid health.

Should you wish to know lots more about other low-cost, low-risk remedies for nail fungus, wart removal and all sorts of other common conditions, check out our People’s Pharmacy Quick & Handy Home Remedy book.

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies..
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  • Tomoda C et al, "Transcutaneous iodine absorption in adult patients with thyroid cancer disinfected with povidone-iodine at operation." Thyroid, June 2005. DOI: 10.1089/thy.2005.15.600
  • Horn-Ross PL et al, "Iodine and thyroid cancer risk among women in a multiethnic population: the Bay Area Thyroid Cancer Study." Cancer Epidemiology, Biomarkers & Prevention, Sep. 2001.
  • Nimmons GL et al, "Urinary iodine excretion after contrast computed tomography scan implications for radioactive iodine use." JAMA Otolaryngology-Head & Neck Surgery, May, 2013. doi:10.1001/jamaoto.2013.2552
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