Evidence-Based Fertility Supplements for Overweight or Obese women:
Written by fertility nutrition expert, Dr. Conor Kerley
Dr. Conor Kerley is a multi-award winning nutrition researcher, leading clinician as well as a member of the European Fertility Society and European Society of Human Reproduction and Embryology (ESHRE).
Overweight, Obesity and Fertility
A large body of scientific research shows that overweight and obesity can negatively affect fertility.
Women with higher body weight may experience:
· Lower ovulation rates
· Reduced natural conception rates
· Lower success rates with fertility treatments
However, understanding why obesity affects fertility helps identify strategies to improve outcomes.
Why Does Overweight or Obesity Affect Fertility?
Several biological pathways link excess body weight to reduced fertility.
1. Insulin Resistance
Insulin resistance is considered one of the major pathways linking obesity to fertility issues.
When insulin levels remain chronically elevated, this can:
- Disrupt ovarian hormone balance
- Increase androgen (male hormone) production
- Impair ovulation
2. Hyperandrogenism
Overweight or obese women often have higher levels of male hormones, including testosterone.
This hormonal imbalance can:
- Disrupt follicle development
- Interfere with ovulation
- Reduce egg quality
3. Irregular Menstrual Cycles
Metabolic disturbances associated with obesity can lead to:
- Irregular cycles
- Delayed ovulation
- Anovulatory cycles (cycles without ovulation)
4. Chronic Inflammation
Obesity is associated with low-grade chronic inflammation, which may negatively affect:
- Egg quality
- Endometrial receptivity
- Implantation success
How Can Fertility Be Improved in Overweight or Obese Women?
The most consistently proven intervention is weight loss.
Randomised controlled trials show that lifestyle or diet-induced weight loss can increase pregnancy rates, particularly in women undergoing fertility treatment.
However, while weight loss is simple in theory, it can be extremely challenging in real life.
Emerging research suggests that specific nutrients may help improve fertility outcomes in overweight or obese women, particularly by targeting metabolic and hormonal pathways.
Evidence-Based Fertility Nutrients for Overweight or Obese Women
Myo-inositol
Myo-inositol is one of the most well-studied nutrients in female fertility, particularly in women with metabolic issues.
In a randomized trial of overweight/obesity women undergoing ovulation induction + IUI, myo-inositol increased clinical pregnancy rates by 34%
Meta-analyses of clinical trials with inositol supplementation have also reported:
· Higher clinical pregnancy rates
· Improved embryo quality
· Better metabolic markers
Myo-inositol may improve fertility through several mechanisms:
- Improves insulin sensitivity
- Reduces hyperandrogenism (high levels of male hormones)
- Helps restore regular ovulatory cycles
These mechanisms are particularly relevant because insulin resistance is a major pathway linking obesity to reduced fertility.
Myo-inositol combination formulas
· A 2023 study published in the journal Fertility and Sterility examined combined supplementation in a large group of overweight or obese women trying to conceive.Myoinositol
· Specific probiotics:
o bifidobacterium animalis
o lactobacillus rhamnous
· vitamins B2,
· vitamin B6,
· vitamin B12,
· vitamin D,
· zinc
Women taking this combined formula experienced a 38% shorter time to pregnancy compared with those who did not.
Omega 3 fatty acids
Omega-3 fatty acids may also play a role in improving fertility outcomes.
A gold standard double-blind randomized controlled trial of omega-3 supplementation during ovulation induction reported:
· Higher clinical pregnancy rates
· This effect was particularly strong effect in overweight/obese women (BMI 25–35). In fact, there was 82% higher pregnancy rates with omega 2 supplementation vs. placrbo
How could these nutrients and supplements improve fertility with overweight/obesity?
· Improves insulin sensitivity and reducing insulin resistance
· Supporting hormonal balance
· Helps restore ovulatory cycles
· Reduced inflammation
· Better endometrial receptivity
N-acetylcysteine (NAC)
NAC is an antioxidant that has shown promise in fertility research, particularly in women with metabolic disturbances or overweight/obesity.
NAC may
Improve ovulation rates
Reduce oxidative stress
Improve insulin sensitivity
Improve pregnancy rates
Targeted Nutritional Support for Overweight or Obese Women Trying to Conceive
Research suggests that these specific nutrients in specific doses offer support for women who are overweight/obese and trying to conceive.
Overweight/obese women trying to conceive should consider targeted metabolic and mitochondrial support including supplementing these 9 nutrients alongside key preconception nutrients such as alpha, lipoic acid, carnitine and iodine.
research-backed nutrients and doses matter. But combining these individual nutrients correctly can be complex, requiring multiple supplements and careful dosing.
Fertility Phix: An All-in-One Fertility Supplement
Fertility Phix was formulated to provide these research-backed nutrients in evidence-informed doses, alongside additional compounds that support:
For women who are overweight or obese and trying to conceive, targeted nutritional support may be a valuable part of a broader fertility strategy.
Explore Fertility Phix or contact us to discuss whether it may be suitable for you.
Who is Fertility Phix suitable for?
Fertility Phix is designed for anyone on a fertility journey who wants a comprehensive blend of research-backed fertility nutrients.
When to start Fertility Phix?
Lifestyle changes, including supplements are recommended for at least 3 months before conception. This is because a woman’s eggs take approximately 3 to 4 months (roughly 90-120 days) to mature – This process is known as folliculogenesis. For this reason, we offer a 3-month bundle, where adding three boxes of Fertility Phix sachets to your cart saves €60 and includes free worldwide shipping.
Key Takeaways
· Overweight and obesity do affect fertility
· Healthy weight loss can improve outcomes but is difficult to achieve and obtain
· Insulin resistance, inflammation and hormonal imbalance play key roles
· Specific nutrients such as myo-inositol, probiotics, B-vitamins, omega-3 and NAC show promise for improving fertility outcomes in overweight/obese women
· Nutritional support should ideally begin at least 3 months before conception
·
Frequently asked questions
Fertility issues are not always female only
Note, regardless of overweight/obesity, fertility issues are NOT female only. Approximately 40–50% of infertility cases involve male factors. These figures highlight the importance of assessing both partners and the importance of a healthy fertility supportive lifestyle for both partners.
If you are a woman trying to conceive, make sure your male partner has been tested, is following a fertility friendly lifestyle and check our these blogs:
Nutrients for Male Fertility, Sperm Quality and sperm count - The Science
Nutrients for Male Fertility, Sperm Quality and sperm motility - The Science
Nutrients for Male Fertility, Sperm Quality and sperm morphology - The Science
Nutrients for Male Fertility, Sperm Quality and sperm DNA fragmentation - The Science
Nutrients for Male Fertility, Sperm Quality and varicocele - The Science
In addition to overweight/obesity, other common conditions contributing to fertility issues in women, include:
Advanced age
Antiphospholipid syndrome
Endometriosis
Fibroids
Hypothalamic amenorrhea
Lupus
Premature ovarian insufficiency (POI)
Thyroid issues, especially Hashimoto's or autoimmune thyroiditis
Please note: This article is for educational purposes only and does not replace personalised medical advice. Nutritional strategies support ovulatory function but do not replace ovulation induction medications (e.g., letrozole) when clinically indicated.
· Not all supplements are appropriate for everyone. Always consult your GP or fertility specialist before starting supplements, particularly if undergoing assisted reproductive treatment.
· Timing matters – lifestyle changes, including supplements are recommended for at least 3 months before conception. This is because a woman’s eggs take approximately 3 to 4 months (roughly 90-120 days) to mature before ovulation, in a process known as folliculogenesis.
· Dosing matters – scientific research has reported benefits of certain doses. It is important to seek out and consume these doses to get the same benefits.
