Is it safe to use melatonin longterm?

May 25, 2022 6:40 PM

From what I've read about melatonin, it's safe to use in the short term, but no studies have been done on long-term use. Have you used it long-term without any ill effects?

I've had on and off issues with insomnia, both falling asleep and staying asleep. I've started taking 300mcg of melatonin occasionally, and it works well. I fall asleep easily and wake up feeling rested. It does give me vivid dreams (not nightmares), but I can deal with that.

Have you been using it long-term? Any side effects that you've experienced?

posted by cozenedindigo to Health & Fitness (9 answers total)

I've used low dose, 150-300mcg, for two years with no issue.

I suspect the warnings mostly apply to high doses, which strongly override your natural melatonin release and may disrupt production over time. No proof tho.
posted by lloquat at 7:25 PM on May 25, 2022

I use a high nightly dose of melatonin but its under the care of a sleep specialist for a specific sleep disorder, so maybe you want the input of a medical professional?
posted by supermedusa at 7:48 PM on May 25, 2022

Anecdotally, yeah I've used it off and on for 20 years or thereabouts. It hasn't caused me any troubles that I know of.

I have insomnia off and on, and when it's not a problem I drop the melatonin cold turkey without any problems. When I'm in an insomnia phase I'll take it every night for weeks or months.

But that's just me. YMMV of course.
posted by DrumsIntheDeep at 9:45 PM on May 25, 2022

Single data point: Yes, I've been taking 5mg nightly for about 4 years now. I am well aware that one is not supposed to do that.

I have health problems: gastritis and hypothyroidism. I'm pretty sure neither is due to the melatonin.

Coincidentally, I had to go without melatonin last night for the first time since that 4 year streak began. I definitely did not sleep great, but that's probably because I was staying with my son in the hospital. I did sleep, though.
posted by commander_fancypants at 11:00 PM on May 25, 2022

I don’t know if it’s a good idea but I’ve been using it almost nightly for years. I take 1mg, which is a lot less than most people seem to take (a lot of the pills are 2-10mg) but more than you do. I have never had to increase my dose from tolerance; on the contrary I have realized that I can get the same benefit from 1mg as larger doses, without the feeling groggy in the morning. I have never had side effects. I have thought about stopping, but it’s just not a high priority for me honestly.
posted by vanitas at 11:24 PM on May 25, 2022

Review article [pubmed], "The Safety of Melatonin in Humans," Clin. Drug Invest. 2016.

Paywalled, but you can plug the doi (10.1007/s40261-015-0368-5) into sci-hub [google.com].

edit: "Similarly, randomized clinical studies indicate that long-term melatonin treatment causes only mild adverse effects comparable to placebo. Long-term safety of melatonin in children and adolescents, however, requires further investigation."
posted by porpoise at 11:35 PM on May 25, 2022

My endocrinologist didn't object to 1mg per day, which seems to have boosted my underactive thyroid nicely - much lower TSH with the same synthroid dose.
posted by I claim sanctuary at 3:01 AM on May 26, 2022

I took 10 mg time release for about 10 - 12 years. It doesn’t seem to have harmed me. When I quit, it only took a couple nights to fall asleep at my normal speed without it and my sleep tracker claims I get more deep sleep now. However, I feel about the same amount rested so I don’t know if I believe that.
posted by hilaryjade at 3:48 AM on May 26, 2022

I didn't know you weren't supposed to take it long term. Whoops. I've been taking 1-3mg per night (whatever is on sale) for around 15 years. No side effects that I'm aware of.
posted by misanthropicsarah at 10:16 AM on May 26, 2022