What is melatonin?
Have you ever wondered how your body knows the difference between day and night? The answer is melatonin.
Melatonin is a naturally occurring hormone released from one of the body's most essential glands - the pineal gland. This gland is located in the centre of the brain.1 Melatonin has grown in popularity over the years, as a medicine used to treat a wide variety of diseases, e.g. sleep disturbances and tumours.1
Biological functions of melatonin
The relationship your body has to day and night is part of the circadian rhythms and helps you live according to changes in your external and internal environments.2 Melatonin has been referred to as 'the light of the night', which is very important in regulating your sleep cycles.2 Consequently, it is mainly released into the bloodstream at night. Melatonin has direct effects on the body's clock. This 'clock' is made up of 24-hour cycles, which are often referred to as 'Circadian Rhythms'. As the brain realises it is getting darker, it releases more melatonin, causing drowsiness. Without the right amounts of melatonin in our body, we would continue to feel awake and alert longer than we should and have issues sleeping.
As melatonin affects other aspects of the body, it is not surprising that some studies have shown that it can help in the following conditions: cancer treatment and prevention, cardiovascular disease, skin damage and liver disease/injury.2
In the UK, melatonin tablets are available on prescription to treat sleeplessness. Unlike the U.S., it cannot be bought as a supplement for sleep as the Medicines and Healthcare Regulatory Agency (MHRA) consider it a ‘medicinal product’, needing a drug license.3
Melatonin and female reproductive hormones
Interactions of melatonin with birth control
As melatonin tablets contain a hormone, this has raised questions about its effect on birth control pills as they also contain hormones.4 Some studies show that melatonin tablets and contraceptive hormones likely affect each other. One such example demonstrated that hormone therapies containing estrogen could increase melatonin levels in the blood, consequently increasing the chance of unwanted side effects.5
Side effects of melatonin and/or birth control
The main side effects of melatonin tablets are as follows:6
- Stomachache or nausea
- Dry mouth
- Feeling irritable or restless
This complete list of side effects can be found on the information leaflet in the packet.
Alternatives for hormonal birth control
Non-hormonal birth control options
You may feel concerned about taking melatonin tablets and birth control pills together. Alternatively, there are a variety of non-hormonal birth control options available, and you can ask your GP, a nurse practitioner or pharmacist questions regarding these.7:
- Copper IUD- A healthcare professional puts this device inside the womb. It contains no hormones, has a failure rate of less than 1% and can be used for ten years.
- Barrier Methods- such as using condoms and contraceptive diaphragms during sexual intercourse.
The link between melatonin and fertility
It is unclear how melatonin tablets, or natural melatonin, can affect fertility. Some research suggests melatonin tablets can enhance fertility in women undergoing fertility treatment.8 On the other hand, another study suggested that melatonin may be beneficial in birth control pills, as it has been reported to inhibit ovulation.9 The differing results could be due to the fact that melatonin levels in women change according to their menstrual cycle.
Melatonin and menstruation
Evidence suggests that melatonin plays a role in the onset of periods, the regularity of periods and the onset of menopause.10 One study found that the relationship between melatonin and light exposure can influence the menstrual cycle.11 However, more research is needed for these effects to be clarified. If you have any concerns about taking melatonin and your menstrual cycle, you can discuss this with your GP.
Melatonin Supplements for Sleep
Other ways to help with sleep
When taking birth control pills, if you feel you are struggling to sleep, there are several alternatives to taking melatonin tablets. This can be a better way to try and encourage sleep if you are worried about the effects these medicines can have on each other. Some great tips for good sleep hygiene are as follows4:
- Not eating a lot of food, or heavy foods, right before sleeping
- Making the bedroom quiet, dark and cool
- Avoiding activities that excite you before sleeping, such as watching a horror movie
- Tracking your sleep schedule using an app or a diary
- Using relaxation techniques such as yoga and meditation
Melatonin is a natural hormone released in the body in response to low light levels. Amongst its many roles in the body, it regulates sleep. In the UK, it can be prescribed by a healthcare professional for sleep issues in the form of tablets. Evidence has shown that birth control pills can increase the levels of melatonin tablets in the blood. This can cause an increase in unwanted side effects, such as drowsiness and nausea. For women concerned about the effects of taking melatonin tablets and birth control pills together, there are several non-hormonal birth control methods.
The direct relationship melatonin tablets have on fertility is still unclear, and evidence has shown opposing effects on the reproductive system. Evidence has also shown that melatonin and its relationship to light exposure can affect a woman’s menstrual cycle from the onset of periods to effects on ovulation. More research is required to clarify these findings further. Any concerns should be discussed with the healthcare provider who supplies your prescriptions.
If you are having trouble with sleeplessness and are taking birth control pills, there are many non-pharmacological ways to improve your sleep. These can be tried before starting melatonin therapy.
- Claustrat, Bruno, et al. ‘The Basic Physiology and Pathophysiology of Melatonin’. Sleep Medicine Reviews, vol. 9, no. 1, Feb. 2005, pp. 11–24. DOI.org (Crossref), https://doi.org/10.1016/j.smrv.2004.08.001.
- Grivas, Theodoros B., and Olga D. Savvidou. ‘Melatonin the “Light of Night” in Human Biology and Adolescent Idiopathic Scoliosis’. Scoliosis, vol. 2, no. 1, Dec. 2007, p. 6. DOI.org (Crossref), https://doi.org/10.1186/1748-7161-2-6.
- Medicines and Healthcare Regulatory Agency. Melatonin[Internet]. 2022 (29th June). Available from: MHRA Products | Search results
- Summer J, Rehman Dr. A. Does Melatonin Affect Birth Control? [Internet]. 2022 (29th June). Available from: Melatonin and Birth Control | Sleep Foundation
- Electronic Medicines Compendium. Melatonin 3mg Film-coated tablets- Summary of Product Characteristics [Internet]. 2022 (29th June). Available from: Melatonin 3 mg film-coated tablets - Summary of Product Characteristics (SmPC) - (emc) (medicines.org.uk)
- NHS UK Medicines. Melatonin. [Internet]. 2019 (29th June).Available from:Melatonin: a manmade hormone used for short-term sleep problems - NHS (www.nhs.uk)
- Britton, Laura E., et al. ‘CE: An Evidence-Based Update on Contraception’. AJN, American Journal of Nursing, vol. 120, no. 2, Feb. 2020, pp. 22–33. DOI.org (Crossref), https://doi.org/10.1097/01.NAJ.0000654304.29632.a7.
- Espino, Javier, et al. ‘Impact of Melatonin Supplementation in Women with Unexplained Infertility Undergoing Fertility Treatment’. Antioxidants (Basel, Switzerland), vol. 8, no. 9, Aug. 2019, p. E338. PubMed, https://doi.org/10.3390/antiox8090338.
- Presl, J. ‘[Melatonin and oral contraception]’. Ceskoslovenska Gynekologie, vol. 58, no. 3, June 1993, pp. 141–42.
- Gail A Greendale, Paula Witt-Enderby, Arun S Karlamangla, Fahima Munmun, Sybil Crawford, MeiHua Huang, Nanette Santoro, Melatonin Patterns and Levels During the Human Menstrual Cycle and After Menopause, Journal of the Endocrine Society, Volume 4, Issue 11, November 2020, bvaa115, https://doi.org/10.1210/jendso/bvaa115
- Barron, Mary Lee. ‘Light Exposure, Melatonin Secretion, and Menstrual Cycle Parameters: An Integrative Review’. Biological Research for Nursing, vol. 9, no. 1, July 2007, pp. 49–69. PubMed, https://doi.org/10.1177/1099800407303337.
- The basic physiology and pathophysiology of melatonin - PubMed (nih.gov)
- Melatonin the "light of night" in human biology and adolescent idiopathic scoliosis - PMC (nih.gov)
- MHRA Products | Search results
- Melatonin and Birth Control | Sleep Foundation
- Melatonin 3 mg film-coated tablets - Summary of Product Characteristics (SmPC) - (emc) (medicines.org.uk)
- Melatonin: a manmade hormone used for short-term sleep problems - NHS (www.nhs.uk)
- An Evidence-Based Update on Contraception - PMC (nih.gov)
- Melatonin - an overview | ScienceDirect Topics
- Circadian Rhythm, Lifestyle and Health: A Narrative Review - PMC (nih.gov)
- Overview of Circadian Rhythms - PMC (nih.gov)
- Circadian Rhythms (nih.gov)