The Role of Antioxidants in Fertility: Supporting Egg Quality, Sperm Health & Progesterone Naturally [EP 55]
If you’ve been trying to conceive for a while, chances are you’ve heard antioxidants mentioned a lot — for egg quality, sperm health, implantation, progesterone, and pretty much everything in between. And while antioxidants absolutely matter, they’re not magic pills. They’re tools. And how, when, and why we use them is what actually determines whether they move the needle for fertility.
In this episode of The Fertility Dietitian Podcast, I’m breaking down what oxidative stress really is, why reproductive cells are uniquely vulnerable to it, and how specific antioxidants like vitamin C, melatonin, NAC, and CoQ10 support egg quality, sperm health, progesterone production, and the uterine lining — when used strategically. This is about working with your biology, not throwing supplements at a problem and hoping for the best.
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“Antioxidants aren’t magic pills — they’re tools. And timing, dose, and context are what make them powerful for fertility.”
What You’ll Learn:
Why oxidative stress impacts egg quality, sperm DNA, progesterone, and implantation
How vitamin C supports the corpus luteum, progesterone production, and uterine lining health
Why melatonin is one of the most powerful — and misunderstood — fertility antioxidants
How NAC and glutathione support ovulation, sperm quality, and detox pathways
Why CoQ10 is foundational for mitochondrial health, egg maturation, and sperm motility
How antioxidants influence implantation, blood flow, and endometrial receptivity
When food alone is enough — and when targeted supplementation makes sense
Why more antioxidants aren’t always better for fertility outcomes
“Egg quality, sperm health, progesterone, and implantation don’t improve because of one supplement — they improve because the environment of those cells becomes safer.”
Supplements Mentioned:
Vitamin C
Melatonin
N-acetylcysteine (NAC)
CoQ10 (ubiquinol form preferred)
Links Mentioned:
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References:
Agarwal A, et al. Role of oxidative stress in female reproduction. Reproductive Biology and Endocrinology. 2012;10:49.
Agarwal A, et al. Oxidative stress and its implications in female infertility – a clinician’s perspective. Reproductive BioMedicine Online. 2012.
Aitken RJ, et al. Reactive oxygen species generation and human spermatozoa: the balance of benefit and risk. BioEssays. 1997.
Henmi H, et al. Vitamin C supplementation increases progesterone levels and pregnancy rates in women with luteal phase defects. Fertility and Sterility. 2003.
Luck MR, et al. Ascorbic acid and ovarian steroidogenesis. Reproduction. 1995.
Halliwell B. Vitamin C: antioxidant or pro-oxidant in vivo? Free Radical Research. 1996.
Tamura H, et al. Melatonin and female reproduction. Journal of Obstetrics and Gynaecology Research. 2014.
Reiter RJ, et al. Melatonin protects against oxidative damage in ovarian follicles. Endocrine. 2009.
Tamura H, et al. Melatonin treatment in infertile women undergoing IVF improves oocyte and embryo quality. Journal of Pineal Research. 2008.
Cirillo F, et al. N-acetylcysteine improves ovarian response and ovulation in women with PCOS. Fertility and Sterility. 2014.
Oeda T, et al. Antioxidant treatment with NAC improves semen quality. Urology. 1997.
Lu SC. Glutathione synthesis. Biochimica et Biophysica Acta. 2013.
Bentov Y, et al. Coenzyme Q10 improves mitochondrial function and fertility outcomes in older women. Aging Cell. 2014.
Turi A, et al. Effect of CoQ10 supplementation on sperm motility and antioxidant status. Journal of Assisted Reproduction and Genetics. 2012.
Balercia G, et al. Coenzyme Q10 treatment improves sperm parameters. Fertility and Sterility. 2009.
Sugino N. Role of reactive oxygen species in the corpus luteum. Reproductive Medicine and Biology. 2005.
Al-Gubory KH. Environmental pollutants and lifestyle factors induce oxidative stress in reproductive tissues. Journal of Reproductive Immunology. 2014.
Gaskins AJ, et al. Dietary patterns and fertility outcomes. Human Reproduction. 2014.
Silvestris E, et al. Obesity as disruptor of the female fertility. Reproductive Biology and Endocrinology. 2018.
Ruder EH, et al. Oxidative stress and antioxidants in female fertility. Human Reproduction Update. 2008.
“Your body isn’t broken. It’s responding to its environment — and that means there’s a lot we can shift.”
Transcript:
Introduction
Welcome back to another episode of The Fertility Dietitian Podcast.
If you’ve been trying to conceive, you’ve probably heard the word antioxidants more times than you can count. Take antioxidants for egg quality. Your partner needs antioxidants for sperm health. Just add an antioxidant supplement.
But like most things in fertility, it’s not that simple.
Antioxidants are not magic pills. They’re tools. And how, when, and why we use them matters — especially when we’re talking about egg quality, sperm quality, progesterone, implantation, and lining support.
Today, we’re breaking it all down.
We’ll talk about oxidative stress and why it’s such a big deal for fertility. We’ll cover vitamin C, melatonin, NAC, and CoQ10. We’ll walk through how antioxidants influence progesterone and the corpus luteum, sperm DNA fragmentation, and uterine lining health.
And as always, this is about working with your biology — not throwing supplements at a problem and hoping for the best.
What Is Oxidative Stress and Why It Matters for Fertility
At its core, oxidative stress is an imbalance.
It happens when your body produces more free radicals than it can neutralize. A small amount is normal and necessary. But when levels get too high, those free radicals damage cells.
Eggs and sperm are especially vulnerable.
Eggs are formed before we’re born. They’re present when our mothers are in our grandmothers’ wombs. Then, each egg that will ovulate goes through a critical maturation window of about three months.
That means the three months before ovulation matter. And so do the three months before that.
Sperm are constantly being produced, but the full process of sperm development takes roughly 80–100 days. They are also highly sensitive to their environment.
Reproductive tissues are metabolically active. They require large amounts of energy. Mitochondria — the energy centers of the cell — are central to fertility and prime targets for oxidative stress.
Eggs contain ten times more mitochondria than any other cell in the body. That makes them powerful, but also vulnerable.
Excess oxidative stress can:
Damage egg and sperm DNA
Impair mitochondrial function
Reduce sperm count, motility, and morphology
Increase sperm DNA fragmentation
Disrupt ovulation quality
Interfere with corpus luteum function
Lower progesterone output
Impair uterine lining development and receptivity
This is why antioxidant support isn’t just about egg quality. It’s about the entire reproductive environment.
Vitamin C, Progesterone & Corpus Luteum Support
Vitamin C is one of the most underrated fertility nutrients.
It plays a key role in supporting the corpus luteum — the structure that forms after ovulation and produces progesterone.
Vitamin C:
Protects luteal cells from oxidative stress
Supports progesterone production
Improves blood vessel integrity
Enhances uterine circulation
Improves iron absorption
Supports endometrial integrity
Progesterone production is metabolically demanding. If oxidative stress is high, the corpus luteum may struggle — even if ovulation technically occurred.
This can show up as:
Short luteal phases
Borderline or low progesterone
Spotting before your period
Unexplained implantation challenges
Vitamin C also supports collagen formation and immune balance within the uterine environment, both essential for implantation.
From a food perspective, vitamin C is not just oranges.
Higher-density sources include:
Kiwi
Bell peppers
Strawberries
Mango
Broccoli
Dark cherries
Citrus zest
Two kiwis a day after ovulation can be a simple way to boost luteal support.
Supplementation can be helpful, especially in the luteal phase, but dosing and timing matter. Context matters. Iron status, inflammation, and stress levels should always be considered.
Melatonin & Egg Quality
Melatonin is one of the most fascinating fertility antioxidants.
It’s known as a sleep hormone, but it’s also a potent antioxidant — especially within the ovaries.
Melatonin concentrates directly in ovarian follicles, where it:
Protects egg DNA from oxidative damage
Supports mitochondrial energy production
Regulates hormone signaling within the ovary
High-quality eggs require efficient mitochondria, low oxidative stress, and strong circadian rhythm signaling.
Sleep and light exposure directly influence melatonin production.
Disrupted circadian rhythm — late nights, excessive screen time, inconsistent sleep — increases oxidative stress within the ovaries.
Before jumping to supplementation, prioritize:
Morning light exposure before screens
Minimizing blue light at night
Consistent sleep timing
7–9 hours of sleep
Cortisol regulation
For many women, especially over 35, low-dose melatonin supplementation (3–5 mg at night) can be beneficial.
Higher doses are not better. In fact, excessive melatonin can interfere with ovulation.
Balance is key.
NAC, Glutathione & Reproductive Outcomes
N-acetylcysteine (NAC) is a precursor to glutathione — the body’s master antioxidant.
Glutathione is critical for:
Egg maturation
Sperm development
Protecting reproductive tissues from toxins
Supporting liver detox pathways
Hormone balance
In women, NAC has been shown to:
Improve ovulation
Support egg quality
Reduce oxidative stress in PCOS
Support inflammatory conditions
In men, NAC can:
Improve sperm count
Improve sperm motility
Reduce sperm DNA fragmentation
Support overall semen quality
NAC is not a “take forever” supplement.
It’s most effective when used strategically — during preconception preparation, periods of high inflammation, or known detox challenges.
Individualization matters.
CoQ10, Mitochondria & Fertility
CoQ10 is foundational for fertility because it directly supports mitochondrial energy production.
Without adequate mitochondrial function, we see:
Poorly matured eggs
Low sperm motility
Compromised embryo development
CoQ10:
Supports ATP production
Protects mitochondrial membranes
Reduces oxidative damage in reproductive cells
In women, CoQ10 has been associated with:
Improved egg quality
Better ovarian response
Improved embryo quality
In men, it has been shown to:
Improve motility
Improve morphology
Improve DNA integrity
Dietary sources include:
Organ meats
Sardines
Beef
Dark leafy greens
Therapeutic levels usually require supplementation, especially with age.
The preferred form is ubiquinol.
General dosing often ranges:
Men: ~400 mg daily (divided doses)
Women: 400–600 mg daily (individualized)
CoQ10 can interfere with sleep, so avoid taking it too close to bedtime.
Use it strategically. It’s an investment supplement, and it should be used wisely.
Antioxidants & Endometrial / Lining Health
Healthy implantation requires a receptive, well-vascularized uterine lining.
Oxidative stress can:
Reduce uterine blood flow
Impair endometrial development
Disrupt immune signaling at implantation
Antioxidant support for lining health includes:
Vitamin C
Vitamin E
Polyphenols from berries and plants
Glutathione support
But lining health also depends on:
Blood sugar balance
Iron regulation
Inflammation control
Nervous system regulation
Antioxidants do not work in isolation. They work within a system.
Food First, Then Strategy
More is not always better.
We do not want to eliminate all oxidative stress. Some is necessary for ovulation, fertilization, and implantation.
The goal is balance.
From food, focus on:
Colorful fruits and vegetables
Berries
Citrus
Kiwi
Herbs and spices
High-quality proteins
Adequate minerals
From supplements, use targeted, lab-informed strategies when appropriate.
Antioxidants are powerful. But they are not shortcuts.
Egg quality, sperm health, progesterone, and implantation improve when the environment those cells develop in becomes safer, calmer, and more supported.
Your body is not broken.
It is responding to its environment.
And when we investigate that environment — instead of dismissing it — we create space for real change.
Thanks for being here. I’ll see you next week.