Melatonin might be one of the more surprising things on an IVF supplement list. It’s the sleep hormone, but it’s also a powerful antioxidant, and it shows up in follicular fluid at higher levels than in your bloodstream. If you’re here to choose a product, our best melatonin supplement for fertility comparison covers brands and doses; this page is about how to use it in a cycle.
Here’s the gist of it in a single paragraph:
”Melatonin is a powerful free radical scavenger and protects the oocyte from oxidative stress, especially at the time of ovulation. The cyclic levels of melatonin in the blood pass through the placenta and aid in the organization of the fetal SCN. In the absence of this synchronizing effect, the offspring may exhibit neurobehavioral deficits. Also, melatonin protects the developing fetus from oxidative stress. Melatonin produced in the placenta likewise may preserve the optimal function of this organ.
Melatonin for Egg Quality
Melatonin treatment significantly increases the number of oocyte collected, mature oocyte, and good quality embryo, as supported by a medical study.
Melatonin acts an assassin, hunting for enemies that may potentially harm your eggs. How exactly?
Melatonin is a free radical scavenger. It neutralises reactive oxygen species (ROS) in your uterus. ROS levels increase especially when its time for your eggs to start maturing.
This is due to an increase in luteinising hormone at the start of the luteal phase (around day 13) — involved in the final maturation and release of the matured oocyte from the ovarian follicle — which stimulates increased mitochondrial function in oocytes, to produce more energy in the form of ATP molecules. The ATP molecules are used to promote the growth and maturation of the oocyte.
However, with increased metabolic rate, there is a higher chance of electron leakage from the electron transport chain in the mitochondria. This forms ROS.
Excessive ROS can oxidise and modify essential enzymes and proteins in the oocyte, disrupting their function. ROS can interact with lipids through lipid peroxidation and cause the oocyte phospholipid membrane to lose its integrity and even rupture.
Additionally, DNA in the oocyte can be damaged by ROS, signalling apoptosis, where the oocyte “commits cell suicide”. All these processes inhibit the proper growth and maturation of the oocyte.
But fret not, melatonin detects and destroys these ROS and protects your eggs from such harm.
Moreover, melatonin’s antioxidant properties allow the delay of ovarian ageing (decrease in number and quality of oocytes). By neutralising ROS, melatonin stops the telomeres of the mitochondrial DNA from shortening, preserving the proper function of the egg’s mitochondria. Mitigating ovarian ageing is crucial in ensuring optimal reproductive health and successful conception.
Read More: Best Melatonin Fertility Supplement: Dose, PCOS & Reviews
Additionally, when the sperm is added to the egg during IVF, the sperm also benefits from the presence of melatonin in the culture media! Melatonin’s ROS scavenging abilities help enhance motility of sperm cells, enabling them to penetrate the oocyte membrane faster.
High-quality oocytes are essential for successful fertilisation, to produce high-quality embryos.
Melatonin can also be injected directly into cultures to promote healthy cell proliferation in the embryo stage.
That’s the mechanism. Most people, though, meet it through one particular book.
What "It Starts With the Egg" Says About Melatonin
Most people arrive at melatonin through Rebecca Fett’s It Starts With the Egg, and the recommendation there is straightforward: 3mg before bed, particularly for IVF, on the basis that melatonin concentrates in follicular fluid and protects the maturing egg from oxidative damage.
That matches the research. Nearly every melatonin IVF trial used 3mg nightly, and the book’s reasoning about oxidative stress is the same mechanism described above.
What the book doesn’t dwell on is the timing problem. Fett’s framing is largely IVF-shaped, where ovulation is controlled by drugs. If you’re trying naturally, taking 3mg nightly through your follicular phase is a different proposition — see the ovulation section below.
So: right dose, right rationale, but check which situation the advice was written for before you start taking it every night. Which brings us to the timing — starting with an IVF cycle.
Melatonin During IVF Stims
In an IVF cycle, melatonin is usually started from around day 3 to 5 of the cycle before stimulation, the protocol most trials used. A study showed that 3-6 mg of melatonin a day was given to patients with unexplained infertility undergoing fertility aid. This helped to control ovarian stimulation until the day of follicular puncture (egg retrieval).
Why is it that with IVF, melatonin can be taken so early?
Our hypothesis is that melatonin’s benefits on improving oocyte quality over-ride the minor disruption it may cause on ovulation. This is because ovulation is already managed by IVF procedures and other medications e.g. GnRH analogs or other drugs that facilitate superovulation.
Additionally, during IVF-ET therapy, FSH is administered. However, there’s a risk of premature ovulation due to a surge in LH. To prevent this, GnRH analogs, either agonists (e.g., leuprolide) or antagonists (e.g., ganirelix), are used. GnRH agonists initially cause an LH surge but then downregulate GnRH receptors, while antagonists rapidly block these receptors.
This careful hormonal control, monitored through ultrasound and hormone levels, prevents premature ovulation, ensuring optimal timing for egg retrieval. The retrieved eggs are then fertilized in the laboratory, and resulting embryos are transferred to the uterus, increasing the chances of successful IVF-ET.
Hence, melatonin is often administered early in the menstrual cycle in the context of IVF, even before ovulation, to capitalise on its benefits in improving egg quality. Melatonin can be taken as an “oocyte quality booster” during IVF.
Which raises the obvious question: when do you stop?
When to Stop Melatonin in IVF
The honest answer is that the research doesn’t tell us. Almost every melatonin IVF trial stopped the supplement at egg retrieval, so that’s where the evidence ends.
The protocols are remarkably consistent: 3mg nightly from around day three to five of the previous cycle, continued until oocyte retrieval. That isn’t a coincidence — these trials were measuring egg and embryo quality, and by retrieval day that outcome is already decided. Nobody designed them to answer what happens afterwards.
So what should you do?
- Up to retrieval: this is the part with evidence behind it. Keep going.
- Fresh transfer: a reasonable case for continuing through the two-week wait, since melatonin supports progesterone production and corpus luteum stability. But that’s mechanism, not trial data.
- Waiting for a future FET: weaker still. The eggs are frozen and their quality is fixed.
- Once pregnant: stop. See the section below on melatonin in pregnancy.
One more thing before you commit to a long protocol. A double-blind trial in 358 women aged 38 to 42 found melatonin improved oocyte and embryo quality but not clinical pregnancy rates. That doesn’t make it useless, but the case for taking it indefinitely is thinner than the internet suggests.
All of this assumes you’re doing IVF. Trying naturally changes the picture, because of one thing melatonin does that nobody mentions.
Can Melatonin Stop Ovulation?
In high doses, possibly — and this is the part that rarely makes it into fertility blogs. Melatonin isn’t only an antioxidant. It also acts on the hormonal signals that trigger ovulation, which matters a great deal if you’re trying naturally and not at all if a clinic is controlling your cycle for you.
Here’s how ovulation normally works:
- The pituitary gland in the brain secretes follicle stimulating hormone (FSH), which stimulates the growth and maturation of ovarian follicles.
- This results in the development of a mature egg which produces estrogen.
- Estrogen, in addition to causing the uterine lining to thicken in preparation for embryo implantation, stimulates the pituitary gland to release luteinizing hormone (LH).
- LH spurs ovulation by triggering the release of a mature egg from the ovary.
And here’s where melatonin interferes:
- Melatonin will bind to the MT1 and MT2 receptors on the neurons in the hypothalamus that release gonadotropins (GnRH).
- This inhibits the neurons from secreting GnRH, and reduced GnRH levels cause the pituitary gland to secrete less LH and FSH.
- If LH is under-secreted, ovulation may not happen as it usually would.
It is advised that women who are trying to get pregnant naturally without IVF should avoid taking exogenous melatonin during the follicular phase (day 1 to 12) of their menstrual cycle.
This appears to be dose-dependent, and the threshold at which it becomes a real risk hasn’t been well established — which is itself a reason to keep the dose conservative when trying naturally.
So the timing matters more without IVF than with it.
Melatonin When Trying to Conceive Naturally
To fully benefit from melatonin’s ROS scavenging abilities, aim to take melatonin during the LH surge phase (as explained in the egg quality section.), that is around day 13, right before ovulation. Avoid days 1 to 12, for the reason explained above.
Melatonin supplementation can be continued during the luteal phase, as it can stimulate progesterone production and stabilise the corpus luteum.
Most fertility clinics prescribe 2-10 mg of melatonin each night for women experiencing infertility issues. A study also showed that a group of women who took 6 mg of melatonin each night for 40 days, one hour before bed, showed higher levels of mature oocytes being released.
Details for nerds:
- Clomiphene citrate is a selective estrogen receptor modulator (SERM). It works by blocking estrogen receptors in the hypothalamus.
- The hypothalamus normally produces GnRH, which signals the pituitary gland to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
- By blocking estrogen receptors in the hypothalamus, clomiphene citrate disrupts the negative feedback mechanism that estrogen typically exerts. This results in an increase in GnRH secretion, which, in turn, stimulates the pituitary gland to release more FSH and LH.
- Clomiphene citrate is usually taken orally for a specific duration of the menstrual cycle, often starting on day 3 or 5 and continuing for several days.
- Ovulation is typically expected around 5 to 10 days after the last dose of clomiphene citrate.
And if it works — if you’re pregnant — the answer changes again.
Can You Take Melatonin While Pregnant?
No. Stop once you have a positive test. Melatonin passes from maternal blood to fetal blood across the placenta, where it may disrupt the fetal circadian rhythm and affect middle/late-stage fetal development.
This is because the fetal circadian rhythm is closely linked to early fetal neurodevelopment. Circadian rhythms influence the release of neurotransmitters, hormones, and growth factors. Proper synchronisation of these biochemical signals is crucial for the formation and maintenance of neural connections, which is essential for normal brain function.
Read More: Is Social Egg Freezing Right for You? A Complete Guide for Women in Singapore
Melatonin for Implantation and Early Development
This is lab and mechanism research. It’s why scientists are interested in melatonin around implantation, not a reason to keep taking it once you’re pregnant. It gets a bit science-y, so skip to the TLDR if you like.
Melatonin also promotes the formation of blastocysts during embryonic development, which is crucial for implantation.
The blastocyst is characterised by two cell types: inner cell mass and the outer layer of cells called the trophoblast layer. Let’s focus on the trophoblast layer for now.
The trophoblast cells release enzymes that facilitate penetration of the trophoblast into the endometrial lining. This promotes formation of the chorionic villi and the placenta, which are both crucial in the exchange of nutrients, oxygen and waste products between the developing embryo and maternal blood. ROS can disrupt such processes, but thankfully melatonin can block ROS action.
Trophoblast cells are extremely sensitive to oxygen levels, which fluctuate during pregnancy. These fluctuations cause hypoxia-reoxygenation (H/R) to occur. Basically, hypoxia = low oxygen levels, whereas reoxygenation = restoration of normal levels of oxygen.
Hypoxia during pregnancy can result from factors such as placental insufficiency, umbilical cord issues, maternal respiratory conditions, anemia, cardiovascular problems, high altitude, smoking, and multiple pregnancies, potentially affecting fetal oxygen supply and development.
Typically, the trophoblast cells are equipped with mechanisms to restore the normal oxygen levels.
Reoxygenation causes increased formation of ROS. This puts the trophoblast cells at risk of H/R induced oxidative damage. This activates a pathway involving Bax and Bcl-2 proteins in the mitochondria. Bax promotes apoptosis while Bcl-2 inhibits it.
Under oxidative stress, the balance shifts in favor of Bax, leading to dysfunctional mitochondria, which release cytochrome c. This promotes formation of apoptosomes that result in DNA fragmentation. This in turn signals for cell death. This process, if occurring excessively, may contribute to fetal tissue damage.
Thankfully, melatonin binds to the MT1 and MT2 receptors on trophoblast cells. As a hunter of ROS, melatonin is thus able to prevent H/R induced oxidative stress and subsequent cell death.
TLDR: Melatonin can pass from the maternal blood into the fetal blood across the placenta, bind to receptors on the cells of the embryo and prevent them from being damaged by ROS.
Read More: NAC Supplement for Women: PCOS, Endometriosis, Fertility & Dose
Melatonin for Unexplained Infertility
It is reported that women with infertility issues have an abundance of ROS in their follicular fluid, thus impacting the release of mature oocytes from their ovaries.
Given the intricate role of oxidative stress, as highlighted in the content above, it may be worthwhile for women facing fertility challenges to explore the potential benefits of melatonin supplements, known for their antioxidant properties.
Melatonin and Myo-Inositol for Fertility
Adding myo-inositol along with melatonin, may improve fertility even more than with melatonin alone. Myo-inositol has been demonstrated to be important for egg quality, ovulation, and hormone balance in women with PCOS.
Myo-inositol is a naturally occurring sugar alcohol with insulin-sensitising properties. Insulin sensitivity is crucial for the proper utilisation of insulin by cells, particularly in tissues like the ovaries. In conditions such as PCOS, insulin resistance is common, leading to hormonal imbalances and disrupted reproductive function.
Insulin resistance is commonly observed in women with PCOS. Elevated insulin levels can stimulate the ovaries to produce excess androgens (male hormones) and inhibit the release of eggs during ovulation.
Read More: Best PCOS Supplements: Inositol, NAC & Myo-Inositol Dose
And that’s not all. Women with insulin resistance may respond less favorably to IVF! Thus, by taking myo-inositol, insulin resistance enhanced, leading to an improve the chances of success with fertility interventions.
So you can think of myo-inositol as a teacher that prepares you for an “exam” (referring to IVF), and melatonin as a cheat sheet during the “exam”.
Of course, as with any other drug, do consult your doctor so that they can designate a customised dosage plan for you.
The case for melatonin IVF comes down to one thing: it’s a strong antioxidant, and it collects in follicular fluid where the egg is maturing. The trials back that up— better oocytes, better embryos. Though it’s worth knowing that in one large trial, those better embryos didn’t lead to more pregnancies.
Two things to keep in mind. If you’re trying naturally, melatonin can interfere with the LH surge you need to ovulate. And it crosses the placenta, so once you’re pregnant, stop.
Beyond that, ask the clinician running your cycle. They know your protocol, and melatonin is one of the few supplements that could actually interact with it.
Who Am I?
Dr. Mark Chern (Ph. D) is a Chinese Medicine practitioner in Singapore, trained in Taipei and active in women’s health since 2011. With over a decade of expertise in treating fertility, pregnancy and various women’s health conditions, Dr Mark is always faced with questions about supplements for fertility and hormone regulation.
He has researched deeply into NAC, Inositol and CoQ10 for fertility. This article covers what the melatonin research actually shows for IVF —the dose, the timing, and where the evidence runs out.
FAQs
Can melatonin help you conceive?
Possibly, though the evidence is stronger for some situations than others. The best case is egg quality — melatonin concentrates in follicular fluid and protects the maturing egg from oxidative stress, and most of the supporting trials were run in IVF cycles. For natural conception the picture is more complicated, because melatonin also acts on the hormones that trigger ovulation. Take it at the wrong point in your cycle and it can work against you.
When to stop melatonin in IVF?
The trials all stopped at egg retrieval, so that’s where the evidence ends. Continuing through a fresh transfer has a reasonable rationale but no trial behind it. Stop once pregnant, and check with the clinician running your cycle.
Melatonin dose for egg quality?
3mg nightly is the dose used in most IVF trials, taken about an hour before bed. Clinics prescribe 2–10mg. Higher isn’t better — dose is where the ovulation risk comes in.
Can you take melatonin while trying to conceive?
Yes, but timing matters. Avoid days 1–12, when melatonin can suppress the LH surge you need to ovulate. Start around day 13 and continue through the luteal phase.
How long do you take melatonin for IVF?
Most trials started on day 3–5 of the cycle before stimulation and ran to retrieval — roughly six to eight weeks. One larger trial began a full month before stims.
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