Resveratrol is a naturally occurring antioxidant compound found in red grapes, berries, and Japanese knotweed that has attracted interest for its potential role in supporting fertility, particularly in women over 40. As ovarian ageing leads to declining egg quality and quantity, some have explored whether resveratrol's antioxidant and anti-inflammatory properties might help mitigate age-related reproductive decline. However, whilst laboratory research shows promise at the cellular level, human clinical evidence remains extremely limited. In the UK, resveratrol is available as a food supplement but is not licensed by the MHRA as a fertility treatment. This article examines the current evidence, safety considerations, and evidence-based alternatives for women over 40 seeking to optimise their reproductive health.

What Is Resveratrol and How Does It Work?

Resveratrol is a naturally occurring polyphenolic compound found predominantly in the skins of red grapes, berries, peanuts, and Japanese knotweed (Polygonum cuspidatum). It belongs to a class of plant compounds called stilbenes and has attracted scientific interest due to its antioxidant and anti-inflammatory properties. In the UK, resveratrol is available as a food supplement and is not licensed by the MHRA as a medicine for fertility or any other indication.

At the molecular level, resveratrol functions as an antioxidant, helping to neutralise reactive oxygen species (ROS) that accumulate with age and contribute to oxidative stress. This mechanism is potentially relevant to reproductive ageing, as oxidative stress can damage cellular components including DNA, proteins, and lipids within oocytes (eggs) and ovarian tissue. Resveratrol also appears to activate sirtuins—proteins involved in cellular repair and metabolism—particularly SIRT1, which plays a role in mitochondrial function.

Resveratrol may modulate inflammatory pathways by inhibiting pro-inflammatory cytokines and enzymes such as cyclooxygenase-2 (COX-2). However, it's important to note that resveratrol has relatively poor bioavailability, with only a small fraction of ingested doses being absorbed and utilised by the body.

Whilst laboratory and animal research shows some promise for resveratrol's effects on cellular mechanisms, human clinical evidence remains very limited, particularly in women over 40 seeking to conceive. The translation of these theoretical mechanisms into clinically meaningful fertility outcomes has not been established and requires further investigation through well-designed clinical trials.

Potential Benefits for Egg Quality and Ovarian Function

Women over 40 experience a natural decline in both the quantity and quality of oocytes, a process termed ovarian ageing. This is characterised by diminished ovarian reserve, increased chromosomal abnormalities (aneuploidy), and reduced mitochondrial function within eggs. Resveratrol has been investigated as a potential intervention to mitigate some of these age-related changes, though the evidence base is still emerging.

Preclinical studies in animal models have suggested that resveratrol supplementation may influence several markers of oocyte quality. Research in aged mice has shown that resveratrol can affect mitochondrial function, reduce oxidative damage, and improve spindle formation during meiosis—the cell division process critical for producing viable eggs. These effects are thought to stem from resveratrol's ability to reduce oxidative stress and support cellular energy metabolism.

In human studies, the evidence is extremely limited. Small-scale preliminary research has explored resveratrol supplementation in women undergoing assisted reproductive technology (ART), but results are inconclusive and insufficient to draw reliable conclusions. Importantly, there is no established evidence that resveratrol supplementation improves pregnancy rates or live birth rates in women over 40.

A Cochrane review examining antioxidants for female subfertility found insufficient evidence to determine whether antioxidant supplements as a group improve fertility outcomes. This highlights the need for caution when interpreting preliminary findings.

It is also worth noting that ovarian ageing is a complex, multifactorial process influenced by genetics, lifestyle, and environmental factors. Whilst resveratrol may have theoretical protective effects at the cellular level, it should not be viewed as a solution for age-related fertility decline. Women considering resveratrol should discuss evidence-based approaches with their GP or fertility specialist.

Recommended Dosage and Safety Considerations

There is no standardised or recommended dosage of resveratrol for fertility enhancement in women over 40, as robust clinical trials establishing optimal dosing are lacking. Research studies have used varying doses, typically between 100 mg and 1,500 mg daily, but these should not be interpreted as recommended doses for fertility purposes.

The European Food Safety Authority (EFSA) has assessed trans-resveratrol as a novel food ingredient and concluded that doses up to 150 mg per day for adults are generally considered safe. However, EFSA specifically notes that safety has not been established for pregnant or breastfeeding women.

Resveratrol is generally considered well-tolerated at moderate doses, with most adverse effects being mild and gastrointestinal in nature, such as nausea, diarrhoea, or abdominal discomfort. Because resveratrol can influence oestrogen metabolism and has mild anticoagulant properties, women with hormone-sensitive conditions or those taking anticoagulant medications (such as warfarin), antiplatelet drugs (such as clopidogrel or aspirin), or NSAIDs should consult their doctor or pharmacist before taking resveratrol due to potential increased bleeding risk.

Important safety considerations include the lack of safety data in pregnant women. Women who conceive whilst taking resveratrol should discontinue use and consult their healthcare provider. Additionally, the quality and purity of supplements can vary considerably, as they are not subject to the same regulatory scrutiny as licensed medicines. Choosing products from reputable UK suppliers that comply with food supplement regulations and have been independently tested for quality is advisable.

If you experience any side effects from taking resveratrol supplements, report them through the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk).

Before starting resveratrol or any fertility supplement, women over 40 should consult their GP or a fertility specialist. A comprehensive fertility assessment should take precedence over unproven supplementation strategies.

Other Lifestyle Factors That Support Fertility Over 40

Whilst resveratrol remains unproven, evidence-based lifestyle modifications are the cornerstone of supporting fertility in women over 40. A holistic approach addressing multiple factors is more likely to optimise reproductive potential than relying on any single supplement.

Nutritional optimisation is fundamental. A balanced diet rich in antioxidants, omega-3 fatty acids, folate, and vitamin D supports overall reproductive health. The Mediterranean diet pattern—emphasising fruits, vegetables, whole grains, legumes, nuts, and oily fish—has been associated with improved fertility outcomes in observational studies. Maintaining a healthy body weight is equally important. The general healthy BMI range is 18.5-24.9, but for fertility specifically, NICE guidance highlights that women with a BMI of 30 or above, and women with a BMI under 19 who have irregular or absent periods, should receive appropriate advice about weight management. Many NHS fertility clinics use BMI thresholds of 19-30 for treatment eligibility.

Smoking cessation is critical, as tobacco use accelerates ovarian ageing and significantly reduces fertility. Women should be offered smoking cessation support through NHS services. The UK Chief Medical Officers' guidance advises that women trying to conceive should avoid alcohol altogether to minimise risks.

Regular physical activity supports metabolic health and may improve fertility, though excessive high-intensity exercise can be counterproductive. The UK Chief Medical Officers recommend at least 150 minutes of moderate-intensity activity weekly. Stress management through techniques such as mindfulness or yoga may also be beneficial, as chronic stress can affect hormonal balance.

Women over 40 should be aware that age is the single most important factor affecting fertility. NICE recommends that women aged 36 and over who have not conceived after 6 months of regular unprotected intercourse should be offered fertility assessment. Initial investigations typically include semen analysis, assessment of ovulation (mid-luteal progesterone), and tubal patency testing when indicated. Earlier referral should be considered for women with amenorrhoea or oligomenorrhoea, suspected or known endometriosis, previous pelvic inflammatory disease, or previous abdominal/pelvic surgery. A comprehensive approach combining lifestyle optimisation, medical assessment, and evidence-based treatments offers the best chance of achieving pregnancy in this age group.

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