Medications · Supplements

Melatonin Before Surgery

Melatonin is one of the gentler supplements around surgery — it's even studied as a way to calm pre-op nerves — but because it adds to sedation, it's still worth mentioning to your team.

Medically reviewed by Dr. Saurabh Shukla, MBBS, DNB Anesthesiology · Last updated June 2026

The short answer

Melatonin is generally low-risk and is sometimes even used to ease pre-op nerves — but it adds to the sedative effect of anesthesia, so tell your team you take it and follow their advice on the morning of surgery.

Why melatonin is a lower-concern supplement

Unlike fish oil or the herbal blood thinners, melatonin doesn't increase bleeding. It's a hormone that helps regulate sleep, and it's actually been studied as a gentle way to reduce anxiety before an operation. The main thing to be aware of is that it can add to the drowsiness from sedation and anesthesia.

What to do

Mention melatonin to your team like any other supplement. Many people can keep taking it for sleep in the run-up; some are asked to skip it on the morning of surgery. If you're taking it for pre-op nerves, there are also other approaches that may help — see calming pre-surgery nerves.

Frequently asked questions

Can I take melatonin the night before surgery?

Often yes, but check with your team. Melatonin is generally low-risk and some anesthetists even use it to ease pre-op anxiety and help sleep. Because it adds to the sedative effect of anesthesia, they like to know you've taken it — so ask rather than assume.

Does melatonin thin the blood like fish oil?

No — melatonin isn't a blood thinner in the way fish oil, vitamin E or the herbal '4 G's' are, so it's a different, lower-risk category of supplement. The main consideration is that it adds to drowsiness around anesthesia.

Should I stop melatonin before surgery?

Many people are advised simply to mention it and follow their team's guidance; some are told to skip it on the morning of surgery. It's lower-concern than blood-thinning supplements, but as with anything you take, disclose it.

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