Q. I am in my 60s and live in Australia. For the past 20 years, I’ve had numerous basal and squamous cell skin cancers removed. Every six months, I’d have to get another check and get something attended to.

About eight years ago, I read about an Australian study on vitamin B3 against skin cancer. I started taking 500 milligrams twice daily. Since then, I have had nothing that needed any treatment. Nothing!

I began seeing my current dermatologist about five years ago and told him what I was doing. He agreed that it is a warranted preventative measure.

The knowledge has been out there for some time but not publicized, to my knowledge. So now, I eagerly tell everyone about it when the subject comes up.

A. The Australians led the way with research on the B vitamin nicotinamide to prevent basal and squamous cell skin cancers (New England Journal of Medicine, Oct. 22, 2015).

Now, American dermatologists have confirmed the benefits of 500 milligrams of nicotinamide twice a day in reducing the risk of skin cancer (JAMA Dermatology, Sept. 17, 2025).

Anyone who has had a skin cancer or a precancerous lesion should talk with their dermatologist about this inexpensive approach to prevention.

Q. I just read that the Food and Drug Administration is planning to ban all natural thyroid preparations. I have been taking Armour Thyroid for decades.

At one point, it became unavailable, and I had to rely solely on Synthroid. I was miserable with brain fog and fatigue no matter what dose my doctor prescribed. I am terrified that I won’t be able to function if the natural desiccated thyroid is taken off the market.

A. This could indeed be quite a problem for hypothyroid people who rely on desiccated extract of animal thyroid glands. When scientists ask patients whether they prefer natural extract, such as Armour, or synthetic levothyroxine like Synthroid, between 10% and 20% of people prefer the natural thyroid.

You can learn more about this from our “eGuide to Thyroid Hormones.” This online resource is found under the Health eGuides at www.PeoplesPharmacy.com.

We understand that AbbVie plans to request approval for Armour Thyroid, but we cannot predict the outcome.

Q. I take Advair for asthma. My insurance company requires that I use a mail-order pharmacy rather than a local drugstore.

I live in Florida, where it is hot and humid outside a good part of the year. Outdoor temperatures are well above the suggested storage temperatures for this medicine. I am not always here to receive it when it is delivered, so it may sit out for hours.

When I contacted the mail-order pharmacy with my concerns, they told me to rent a box at the post office if I wanted properly maintained temperatures!

A. You are not the first reader to report problems with mail-order medicines. The official instructions on storage for Advair (fluticasone + salmeterol) call for storage at room temperature (68 to 77 degrees F). Short “excursions” allow for temperatures to reach as high as 86 degrees.

We think it’s unreasonable for a mail-order pharmacy to require customers to rent post office boxes. Moreover, it is an incomplete solution. Most trucks that transport mail are not climate-controlled. The best way to know if your meds have been maintained properly during shipping would be if the mail-order pharmacy included a temperature and humidity sensor with the medicine.

In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of King Features, 300 W. 57th Street, 41st Floor, New York, NY 10019, or email them via their website: www.PeoplesPharmacy.com. Their newest book is “Top Screwups Doctors Make and How to Avoid Them.”