Melatonin and Fertility: The Antioxidant Shield That Protects Your Eggs and Cellular Health

Hello, I am Dr. Isabel Viña Bas, physician and Scientific Director of IVB Wellness Lab. In my practice, there is a molecule that carries an unfair stereotype: melatonin. Almost everyone knows it only as "la hormona del sueño", that pill you take at night for jet lag or when insomnia hits hard.

But my job is to help you know more so you can fear less and choose better, and here that starts by recognizing something that surprises most of my patients: melatonin is one of the most potent antioxidants and cellular protectors that your body produces, playing a decisive role in an unexpected area: reproductive health and the quality of your eggs.

Reducing it to a simple sleep inducer ignores its real function: guardian of the redox balance at the mitochondrial level. That is the gateway to understanding its impact on your fertility

What is melatonin and why is it produced throughout your body

The pineal gland synthesizes melatonin at night to synchronize your circadian rhythms—everyone knows that. What science has been revealing in recent years is that it also it is produced locally in the skin, gut, pancreas, and ovaries, actuando ahí mismo, dentro de esas células.

melatonin easily enters all cellular compartments.

I like to explain this with a simple analogy: mitochondria are like your kitchen at home. That's where you have the stove on, where you cook to get energy (ATP). But cooking messes up the countertop, crumbs fall, grease splatters, and smoke is generated. Those waste products, in your cell, are free radicals. Coenzyme Q10 and melatonin are the ones that clean up that oxidative waste on a daily basis, without them, the cell ends up suffocated by its own smoke.

Melatonin and female fertility: why your egg needs a "super chill" environment

the relationship between melatonin and female fertility you have to go down to the ovary. Each egg matures inside a follicle, floating in a watery medium: the follicular fluid.

For the egg to mature properly, become fertilized, and for the embryo to implant in the uterus, that liquid needs to be a neutral environment, practically free of oxidizing substances, something like "super chill". The problem is that our lifestyle (chronic stress, lack of rest, alcohol, pollution) floods that liquid with free radicals and toxins.

egg quality declines, it becomes harder to conceive, and the risk of miscarriage increases magnesium

The melatonin paradox: why do I recommend taking it during the day for fertility?

One of the questions we receive most often in customer service when a woman starts with FertiUp, nuestro complemento alimenticio de fertilidad avanzada, es: "Isa, si esto lleva melatonina, ¿no me va a dar un sueño terrible si me lo tomo antes de ir a trabajar?". La respuesta es no, y la explicación biológica merece la pena.

The sleep-inducing effect of melatonin depends on synchronizing your central biological clock, the brain's suprachiasmatic nuclei, in the absence of light. If you take it in a precision dose (the 1.9 mg in FertiUp) and you are exposed to ambient light during the day, that effect on the brain is canceled out.

Upon swallowing the capsule, the melatonin travels directly to your tissues, entering the ovarian and endometrial tissue, where it acts solely at a peripheral level as a cellular protector and mitochondrial antioxidant. Protege tus óvulos sin robarte energía en tu día.

Why you shouldn't take melatonin chronically: Risks and side effects

With all its power against free radicals, I am uncompromising here: I do not recommend taking melatonin dietary supplements every night, for years, to sleep. It is a potent hormone, and its uninterrupted use (I know patients who have been taking it every night for 5 or 10 years without a prescription) concerns me for four reasons:

You block your own production. Continuous exogenous melatonin can cause your pineal gland to "become lazy" and reduce or stop its natural production through negative feedback.

You worsen glucose metabolism. Melatonin and insulin are physiological enemies. At night, insulin resistance naturally increases to prevent hypoglycemia while you fast. If you have a late dinner, at 22:00, and take melatonin right after, that resistance rises even further: it worsens sugar metabolism and promotes abdominal fat.

You alter the reproductive hormonal axis. If abnormally elevated, melatonin downregulates the reproductive system. At the brain level, it reduces the conversion of T4 to active T3 (modifying deiodinases); this drop in T3 lowers GnRH, and with it, LH and FSH in the pituitary gland. In men, it can reduce testosterone and sperm quality, and even cause testicular atrophy; in women, it lowers estradiol and progesterone and can inhibit ovulation, something we frequently see in hypothalamic amenorrhea.

You affect rest itself. In many patients, common exogenous melatonin causes nightmares, restless awakenings, and drowsiness the next day, especially with cheap, non-sustained-release versions: they produce a peak at 50 minutes and a sharp drop that wakes you up wide awake in the middle of the night.

is taken with a start and end date, only during the 3 or 4 months of active pregnancy planning. Ahí el beneficio de proteger el óvulo supera cualquier riesgo, y el cuerpo no tiene tiempo de generar tolerancia.)

The biochemistry of sleep: how to produce melatonin to sleep naturally

If you want to sleep well, forget about hormone patches. It is much better to give your body the raw materials so that your own brain manufactures GABA and its own melatonin. It's like giving you the flour, the egg, the cinnamon, and the chocolate to make the cake yourself, instead of giving it to you already made.

el amino acid tryptophan, which is converted into 5-HTP and then into serotonin and melatonin. Esa conversión depende de un proceso de metilación correcto, con donadores de metilo (SAMe) y cofactores como la B12 activa (metilcobalamina) y el folato activo (Quatrefolic®).

And this is where our star ingredient for rest comes in: NordicCherry®, tart cherry extract. Rich in polyphenols, it not only reduces muscle soreness, but also inhibits the activity of the IDO enzyme, which destroys tryptophan in the brain. By lowering IDO, more free tryptophan is left to produce your own serotonin and melatonin, which translates into a deep sleep without nightmares.

That's why I formulated SomniLove: un reparador del descanso sin melatonina, with 4.1 grams of pure glycine (which lowers core body temperature as a biological sleep trigger), L-theanine, lemon balm, and passionflower to calm the mind (shifting from beta to alpha waves) and sleep straight through.

How to incorporate melatonin into your fertility protocol day by day

Consistency is key here. Respecting cellular biochemistry, day after day, is what makes the difference compared to a one-off dose.

If the pregnancy test comes back positive, the egg preparation work is done VitalNatal Woman to GestaNatal 9 months of gestation.

You hold in your hands the knowledge needed to balance your hormones and reclaim your biological well-being.

Author: Dr. Isabel Viña Bas 

I hope you like it :)

For more information, you know you can find me on my Instagram @isabelvina, where I share daily content with you 
My TikTok @isabelvinabas
On my YouTube channel YouTube Channel
And the supplements formulated by me on my website My website