Is melatonin safe while trying to conceive?

What does the evidence say about melatonin safety while trying to conceive?

1. An older study found that high-dose melatonin lowered levels of key hormones needed to conceive, potentially making it harder to get pregnant, though this research is dated and limited. 1
2. A systematic review of melatonin in assisted reproduction found it significantly improved fertilization rates and markers of egg quality, using doses of 1 to 8 mg a day in most studies, but found no significant difference in clinical pregnancy rates. 2
3. Because melatonin is sold as a dietary supplement, it's regulated less strictly than a prescription or over-the-counter drug, and one study found most products didn't match their labeled dose, with about 26% also containing serotonin. 3
4. Long-term melatonin use has been associated with reduced semen quality in men, and the same source advises that pregnant and breastfeeding women should avoid it given how little safety data exists. 4
5. Studies specifically looking at melatonin for infertility haven't found a higher miscarriage rate, and research so far hasn't suggested an increased chance of birth defects, though human data remains limited. 1

What to know about melatonin safety while trying to conceive

• If you're just starting to try, know that melatonin can suppress the LH surge that triggers ovulation in some research, so nightly use right when you're aiming to conceive isn't clearly risk-free for timing a pregnancy.
• In fertility-clinic settings, melatonin taken around egg retrieval has been linked to better egg and embryo quality markers, but that hasn't translated into a higher clinical pregnancy rate in the same studies, so it isn't a proven way to speed up conceiving on your own.
• If you do conceive while taking melatonin, mention it to your provider at your first visit, since human pregnancy safety data is still limited and general guidance leans toward pausing supplement use once you know you're pregnant.