Can Melatonin Cure Cancer?

Doctor Frank Shallenberger

Dr. Frank Shallenberger, MD

March 10, 2025

 
Old man taking melotonin

Everybody knows that melatonin is important for sleep. But even if you sleep like a baby, if you are over the age of 40, you should be taking melatonin.

There are four very remarkable and unexpected effects of taking melatonin:

• protects against viral and bacterial infections

• prevents cardiovascular disease and high blood pressure

• reduces oxidant stress and inflammation and slows aging

• improves brain function as you age

But that’s not all you can expect when you take melatonin. Melatonin actually prevents and treats cancer.

Who would have guessed that melatonin is one of the best anti-cancer supplements you could ever take? I treat a lot of patients with cancer. I believe one of the most important things I can give them is melatonin. Here’s why.

Researchers looked at all of the controlled studies published on the use of melatonin in patients with cancer from 1993 to 2004. They were specifically looking at survival rates during the first year of treatment. They included trials that used melatonin as either the only treatment given or when it was given along with other treatments such as chemotherapy or radiation. The results were astounding.

On average, melatonin reduced the risk of dying by 44%! If results one-tenth this good happened from the use of a $20,000 per month drug, Big Pharma would have been touting it as the next great thing. But that’s not all. The effects were consistent no matter what dose they used. And none of the patients had any significant side effects from the melatonin.

The authors put it this way, “The substantial reduction in risk of death, low adverse events reported, and low costs related to this intervention suggest great potential for melatonin in treating cancer.”

Despite incredible data like this, oncologists continue to be suspicious of using a natural substance along with their chemo or radiation. For reasons that always prove to be false, they keep suggesting that natural substances will somehow interfere with their therapies. And that’s why a brand new animal study is so important.

The researchers took a group of rats who had estrogen-positive breast cancer and divided them into four groups. One group received no treatment at all. They gave the second group melatonin. The third group got a chemo drug called adriamycin. They also gave the fourth group a combination of adriamycin and melatonin. Then they measured the amount of tumor growth, the microscopic changes in the tumors, and the survival rate of the animals after one month. Once again, the results are incredible.

Did the melatonin interfere with the chemo drug? Absolutely not. In fact, the tumors were smaller and the amount of microscopic tumor cell injury was higher in the group that had the combination of melatonin and chemo than they were in the chemo-only group. Melatonin not only did not interfere with the drug, it actually improved the results. This is what I see 100% of the time when I combine natural therapies with conventional therapy for cancer.

But that’s not all the researchers found. The group that had the highest one-month survival was the group that got the melatonin all by itself. And the one that had the most side effects and were the sickest was the one that had the drug by itself. The researchers concluded that adding melatonin to chemotherapy enhanced the treatment effect of the drug while at the same time it decreased the side effects. But why?

In their words, it’s because, “Melatonin has been shown to play a fundamental part in neuro-immunomodulation.” This means that it improves the way the immune system is able to kill the tumor. They also found that melatonin has its own direct action on tumor cells that kills them just like chemo does.

Once again, in their own words, “A number of studies have documented that when given in combination with chemotherapy to patients with disseminated disease, melatonin increases the overall one-year survival and reduces toxic side effects.” This is why it should be used in every cancer case — it works!

So should you be taking melatonin even if you sleep well? I say yes. The data that I have presented to you from nine different papers on melatonin speaks for itself. But don’t you need to check blood levels? Not if you’re older than a teenager. The body peaks out in melatonin production during puberty.

After that, it’s all downhill. By the time you hit 20, you’re already deficient in the hormone. Studies on the urinary metabolite of melatonin, 6-sulfatoxymelatonin, show that it decreases steadily with age. By the time you’re 50, your levels of production are seriously low. So if you want to have all of the benefits of melatonin, you’re just going to need to take it on a regular basis.

I routinely give 1 mg per pound of body weight of melatonin per day to my patients fighting cancer and have never seen one side effect. I regularly take that much myself and have felt great ever since I started.

And by the way, I used to come down with a virus once or twice a year. Since I started taking melatonin in that dose, viral infections have become a thing of the past. Will melatonin cure cancer? Not all by itself. But, as you can see, it offers huge benefits to anyone fighting cancer. And three last notes.

One, there are a few people out there who are sensitive to even very small doses of oral melatonin.

I have talked about this before. For this small group, melatonin when taken as a pill can interrupt sleep and/or cause a hangover feeling in the morning. But if you’re one of these people, there’s some good news. You can still take melatonin. For some reason, people who cannot tolerate melatonin in small doses can tolerate it well when given in much higher doses, such as 20-40 mg.

You can also take melatonin as a topical cream instead of a pill. It does not have this effect when you take it as a cream.

Two, the form of melatonin that I use in the clinic is the 60 mg capsules from https://carefast.com. You can get melatonin cream online at Amazon.

Three, you might think that this report is a complete report on all the new developments with melatonin. But you would be wrong. There is more. This is just the beginning. So take your melatonin and stay tuned for more reasons to keep taking it.

Yours for better health,

Frank Shallenberger, MD

REF:

Ma, C., L.X. Li, Y. Zhang, et al. “Protective and sensitive effects of melatonin combined with adriamycin on ER+ (estrogen receptor) breast cancer.” Eur J Gynaecol Oncol. 2015;36(2):197-202.

Mills, E., P. Wu, et al. “Melatonin in the treatment of cancer: a systematic review of randomized controlled trials and meta-analysis.” J Pineal Res. 2005 November;39(4):360-6.

Vinther, A.G., and M.H. Claësson. “The influence of melatonin on the immune system and cancer.” Ugeskr Laeger. 2015 May 18;177(21).

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