Q: I used castor oil mixed with baking soda to treat a prominent actinic keratosis that I’d had for years. It was gone after two days and hasn’t come back two years later. I can’t remember where I heard about this remedy, but others might want to know about it.

A: Actinic keratoses are precancerous skin lesions. They are common on aging skin that has been exposed to ultraviolet radiation from the sun and may feel scaly or rough. Sometimes they itch or burn. All such spots should be seen by a dermatologist, as they could be an early form of skin cancer.

You are not the first person to report that castor oil could help an actinic keratosis, though other readers did not include the baking soda. We could not find any published studies of this remedy, but it seems benign. If it doesn’t work, the dermatologist can use a more standard approach such as freezing it off (cryotherapy) or applying a medicine like 5-fluorouracil cream, imiquimod cream or ingenol gel.

Q: When is a good time to take melatonin? Typically I go to bed at 10:30 p.m. and read for an hour before lights out. I often awaken at 1 or 2 a.m. and can’t fall back to sleep.

A: Melatonin appears to be most helpful if taken 30 minutes to an hour before sleep. In your case, that would mean taking it at bedtime.

Although melatonin could help you fall asleep more quickly (Neurological Research, June 2017), we don’t know whether it will help you stay asleep. A prolonged-release formulation might be useful for that purpose (Expert Opinion on Pharmacotherapy, April 2012).


You can learn more about melatonin and other nondrug approaches to overcoming insomnia in our eGuide to Getting a Good Night’s Sleep. Look for this online resource in the Health eGuides section at peoplespharmacy.com.

Q: I have restless legs syndrome, which keeps me awake at night unless I take a magnesium supplement at bedtime. This gives me excellent results.

On the rare occasion that I get that creepy-crawly feeling anyway, I rub magnesium oil on my lower legs. This helps almost immediately, and I am able to go back to sleep.

A: Restless legs syndrome (RLS) was first described in 1944 by a Swedish neurologist, Dr. Karl-Axel Ekbom. People with this condition describe an unpleasant creeping or crawling sensation in the legs that is relieved by moving them. RLS mostly happens when the person is resting, and it frequently interferes with sleep.

Many people report that magnesium supplements can help with insomnia, RLS and leg cramps. Unfortunately, we found only one uncontrolled study on magnesium therapy for RLS (Sleep, August 1998). In this “open” study, people with RLS or a related problem, periodic limb movement during sleep, took magnesium supplements and found them beneficial. We wish that scientists had followed up on this approach.

One important warning: People with limited kidney function must not take supplemental magnesium. It could overwhelm the kidneys and build up to dangerous levels. It isn’t clear whether topical magnesium oil would provide enough magnesium to be dangerous, but it wouldn’t make sense to push the envelope.

Another mineral that might be helpful for treating RLS is selenium. Swedish scientists reported on a handful of cases in which people with severe RLS took 100 micrograms of selenium daily and experienced noticeable improvement (Iranian Journal of Neurology, Oct. 7, 2016).