The Role of Melatonin in Fertility


Most of us have heard about melatonin in the context of sleep, as a supplement that can impact our circadian rhythm. However, this hormone also plays an important role in female fertility. 

What is Melatonin? 

Melatonin is a hormone made by the pineal gland in our brains. It  regulates our sleep wake cycle and is a potent antioxidant. The secretion of melatonin increases in the dark, and can be disrupted by both natural and artificial light sources. Levels of melatonin also decrease with age. 


Melatonin and Fertility

Melatonin is found in high levels in the ovary. Melatonin is contained in the follicular fluid which surrounds the ovarian follicle- where the egg or ovum is found. Knowing the close proximity of this antioxidant to the egg, researchers have looked at the role that melatonin has in egg quality and pregnancy outcomes. 

Several studies have found an increased success in IVF treatments in women with higher levels of melatonin.  

In a 2017 study, melatonin levels in the follicle were measured and higher melatonin levels were correlated with increased IVF outcomes. More eggs were collected from those with higher melatonin levels which led to an increased number of high quality embryos and a more successful implantation.1

In another study, patients undergoing two cycles with reproductive technology were given melatonin for two weeks and their egg quality was compared to a cycle without melatonin. In the cycle with melatonin, fertilization rates increased to 77.5% versus the non melatonin cycle (69.3%). Those who had a low fertilization rate in the non-melatonin cycle saw an even more dramatic increase in fertilization with the melatonin.2

How Does it Work?  

We don’t know exactly how melatonin improves IVF outcomes, but it most likely has to do with its antioxidant properties. As mentioned previously, melatonin is an antioxidant, meaning it inhibits the process of oxidation. When cells become oxidized, they create free radicals which damages the cell. By reducing the amount of damage to the egg cells, melatonin increases egg quality, leading to higher fertilization rates during IVF. So, the antioxidant properties of melatonin may be one of the ways it works to enhance fertility outcomes. 

Another possible mechanism is through melatonin’s ability to regulate our circadian rhythm. In a study done at Harvard University, 500 women undergoing IVF were studied for the impact of shift work on fertility.4 The study found that those who worked only during the day produced 2.5 more eggs after stimulation when compared to women working night shifts. The authors believe that the disruption in circadian rhythm may prevent more eggs from maturing in those women who work nights. Therefore, if you are a shift worker, it may be even more important to seek assistance in obtaining adequate melatonin levels!

Natural Ways to Increase Your Melatonin 

Melatonin is a hormone produced by our bodies, so the first step to increasing this fertility friendly antioxidant is to make sure we are not decreasing our own secretion. 

Some ways to make sure your body is producing enough melatonin are:

  • Make sure you’re sleeping in a dark room, try blackout curtains if you’re getting too much light. 
  • Turn off your devices at night (tablets, phones, TV) or at least try turning down the brightness or putting on “night mode” if available. 
  • Try blue blockers which decrease the amount of blue light getting to your brain. Blue light can throw off our circadian rhythm and lead to decreased secretion of melatonin.
  • Have a regular sleep-wake schedule and going to bed before midnight can regulate your melatonin production. 


Melatonin Supplementation 

Although most studies use around 3mg when supplementing, the dosage of melatonin is highly individualized and may not be for everyone. In practice, I have found that a small number of patients are quite sensitive and supplementing may lead to feeling tired, having vivid dreams causing disturbed sleep. This is a rare, but possible side effect, and in these patients I recommend discontinuing. Melatonin at high doses has also been shown to possibly decrease ovulation in one study.3  The timing of melatonin supplement is also important and can throw off your sleep-wake cycle if taken at the wrong time of day. This doesn’t mean you should be scared of trying melatonin, it just means that using this supplement should be guided by a qualified health care provider, rather than you trying it on your own. 

Whenever trying out a new supplement, it is important to reach out to a healthcare provider to ensure your safety and to make sure this treatment is right for you. In practice, I often run a DUTCH test (comprehensive urine hormone test) which actually tells me whether you are deficient in melatonin or have sufficient amounts. This helps to guide me as to whether or not melatonin supplementation would offer any advantage for egg health in that individual. 

At Awaken Life, I take an individualized approach to treatment and I am here to support you throughout your fertility journey.  


With love and in health,


  1. Tong J, Sheng S, Sun Y, Li H, Li WP, Zhang C, Chen ZJ. Melatonin levels in follicular fluid as markers for IVF outcomes and predicting ovarian reserve. Reproduction. 2017 Apr 1;153(4):443-51.
  2. Seko LM, Moroni RM, Leitao VM, Teixeira DM, Nastri CO, Martins WP. Melatonin supplementation during controlled ovarian stimulation for women undergoing assisted reproductive technology: systematic review and meta-analysis of randomized controlled trials. Fertility and sterility. 2014 Jan 1;101(1):154-61.
  3. Voordouw BC, Euser R, Verdonk RE, Alberda BT, de Jong FH, Drogendijk AC, Fauser BC, Cohen M. Melatonin and melatonin-progestin combinations alter pituitary-ovarian function in women and can inhibit ovulation. The Journal of Clinical Endocrinology & Metabolism. 1992 Jan 1;74(1):108-17.
  4. Mínguez-Alarcón L, Souter I, Williams PL, Ford JB, Hauser R, Chavarro JE, Gaskins AJ. Occupational factors and markers of ovarian reserve and response among women at a fertility centre. Occup Environ Med. 2017 Jun 1;74(6):426-31

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