Swanson Resveratrol 250mg Higher Potency 30 capsules from Polygonum cuspidatum — available in Ireland from Probiotic.ie

Resveratrol Ireland: Longevity, SIRT1 & Evidence Guide

Evidence Guide · Resveratrol Ireland · April 2026

Resveratrol is one of the most studied polyphenols in longevity research. Its proposed interaction with SIRT1 — a NAD⁺-dependent enzyme in cellular ageing pathways — has made it central to the emerging science of sirtuin biology. This guide covers what the clinical evidence actually shows, what it does not, and how to approach resveratrol supplementation intelligently in Ireland.

Quick Answer

Resveratrol is a polyphenol from Polygonum cuspidatum root (Japanese knotweed) studied for its proposed modulation of SIRT1 (Sirtuin-1) — a NAD⁺-dependent enzyme involved in cellular stress response, DNA repair, and metabolic regulation. Howitz et al. (Nature, 2003) first identified resveratrol as a compound with SIRT1-modulating properties; Baur et al. (Nature, 2006) demonstrated improved health markers in obese mice. Human clinical data exists for cardiovascular markers, glucose metabolism, and cognitive performance — longevity effects in humans have not been established in RCTs. In Ireland, resveratrol is a food supplement under FSAI guidelines. It is not a medicine.

Evidence Summary

What is well-supported: Resveratrol has preclinical evidence (yeast, mice) for SIRT1 pathway modulation and human trial evidence for selected metabolic, cardiovascular, and cognitive markers in specific populations.

What is not proven: No published human clinical trial has demonstrated that resveratrol extends lifespan. Longevity effects remain a biologically plausible hypothesis, not an established clinical finding.

Most relevant human dose range: Several trials have used 200–250mg daily, matching the Swanson 250mg formulation. Results are population-specific and mixed across endpoints.

Key safety note: Resveratrol may interact with blood-thinning medication and is not suitable during pregnancy or breastfeeding. Consult your GP if on any prescription medication.

Feature Specification Evidence Level
Primary source Polygonum cuspidatum root (Japanese knotweed) High — standard industry source for trans-resveratrol
Active isomer Trans-resveratrol High — form used in published clinical research
Proposed mechanism SIRT1 pathway modulation via NAD⁺-dependent deacetylase Moderate — strong preclinical, mixed human data
Human trial dose range 10mg–2,000mg daily; most metabolic studies at 200–250mg Moderate — endpoint and population specific
Lifespan extension in humans Not established No human RCT evidence
Key drug interaction risk Anticoagulants and antiplatelet medications Consult GP before use if on blood thinners
Overview

What Is Resveratrol?

Resveratrol (3,5,4′-trihydroxystilbene) is a stilbenoid polyphenol produced naturally by plants under stress — fungal attack, UV radiation, drought, and physical injury. It acts as a phytoalexin: a chemical defence compound synthesised in response to environmental threat.

The highest-concentration natural sources are Polygonum cuspidatum (Japanese knotweed) root, red grape skins, and, to a lesser extent, blueberries, peanuts, and dark chocolate. The red wine connection — which launched resveratrol into mainstream awareness in the 1990s following research by Serge Renaud and Michel de Lorgeril on the French Paradox — is real but misleading in practical terms. A standard glass of red wine contains approximately 0.2–2 mg of resveratrol. Supplement products deliver 50–500 mg per dose.[1]

Most commercial resveratrol supplements, including Swanson Resveratrol 250mg Higher Potency, use Polygonum cuspidatum root extract as the primary source — the most concentrated and cost-effective botanical source available. In Ireland, resveratrol is classified as a food supplement under the European Communities (Food Supplements) Regulations 2003, enforced by the FSAI.

Regulatory Note — Ireland

Resveratrol is sold in Ireland as a food supplement, not a medicinal product. No health claims for resveratrol are currently authorised under EC Regulation 1924/2006 as applied in Ireland. Supplement products cannot claim to extend lifespan, treat disease, or produce medicinal effects. Clinical and mechanistic content in this article is educational — it does not represent authorised claims for any product.

250mg
Per Swanson capsule (Polygonum cuspidatum)
2003
Howitz et al. — first SIRT1 activation paper, Nature
7
Human sirtuin proteins (SIRT1–SIRT7)
<1mg
Resveratrol per glass of red wine
Longevity Mechanism

SIRT1, Sirtuins and Longevity Pathways

The scientific case for resveratrol as a longevity compound centres on its relationship with sirtuins — a family of NAD⁺-dependent protein deacetylases involved in regulating cellular stress responses, DNA repair, mitochondrial function, and gene expression.

Mammals have seven sirtuin proteins (SIRT1–SIRT7). SIRT1 is the most studied and is considered a master regulator of metabolic and stress response pathways. When cells are under caloric restriction — the most reliably documented longevity intervention in animal models — SIRT1 activity increases. Resveratrol appears to mimic some aspects of this response.[1]

The landmark 2003 paper by Howitz KT, Bitterman KJ, Cohen HY, and Guarente L (MIT) and Sinclair DA (Harvard Medical School), published in Nature, identified resveratrol as a small-molecule compound with SIRT1-modulating properties. The study showed resveratrol extended lifespan in Saccharomyces cerevisiae (yeast) by up to 70% — generating significant scientific and mainstream interest.[1]

In 2006, Baur JA, Pearson KJ, Price NL, and Sinclair DA (Harvard Medical School) published results in Nature showing that resveratrol improved health and survival in obese mice on a high-calorie diet, improved insulin sensitivity, and increased mitochondrial biogenesis via SIRT1 and PGC-1α pathways.[2]

🔬
SIRT1 Pathway Modulation

Resveratrol is proposed to modulate SIRT1 (Sirtuin-1), a NAD⁺-dependent deacetylase. SIRT1 removes acetyl groups from proteins including p53, NF-κB, and PGC-1α — influencing DNA repair, inflammation, and metabolic regulation. The exact mechanism of resveratrol's interaction with SIRT1 remains an active area of research.

Mitochondrial Biogenesis

SIRT1 deacetylates PGC-1α (peroxisome proliferator-activated receptor gamma coactivator 1-alpha), which drives mitochondrial biogenesis. More mitochondria per cell is associated with improved metabolic efficiency and reduced oxidative stress.

🧬
NAD⁺ Pathway Connection

Sirtuins require NAD⁺ to function. Cellular NAD⁺ levels decline with age. Resveratrol's proposed SIRT1 activation and NMN's proposed NAD⁺ replenishment are therefore complementary — acting on different points of the same pathway.

🛡️
Antioxidant Activity

Resveratrol is a direct free-radical scavenger and upregulates endogenous antioxidant enzymes. Oxidative stress is a key driver of cellular ageing — accumulated DNA damage from reactive oxygen species contributes to cellular senescence and dysfunction.

🔥
Anti-Inflammatory Pathways

Resveratrol inhibits NF-κB, a key transcription factor in inflammatory signalling. Chronic low-grade inflammation — sometimes called "inflammaging" — is associated with accelerated biological ageing and increased risk of age-related conditions.

🔁
AMPK Activation

Resveratrol activates AMPK (AMP-activated protein kinase) — the same cellular energy sensor activated by exercise and caloric restriction. AMPK activation inhibits mTOR, a pathway associated with cellular ageing when chronically overactive.

Important Context on Longevity Claims

Most mechanistic longevity data for resveratrol is preclinical — established in yeast, fruit flies, nematodes, and mice. Whether proposed SIRT1 modulation by resveratrol translates to meaningful longevity or healthspan outcomes in humans is not established by current clinical evidence. No supplement product in Ireland can claim to extend human lifespan. The sirtuin biology is well-documented; the human application remains an active research question.

Bioavailability

Trans-Resveratrol vs Cis-Resveratrol: Why It Matters

Resveratrol exists in two structural isomers: trans-resveratrol and cis-resveratrol. The distinction matters for supplement quality.

Trans-resveratrol is the more stable isomer and the form studied in virtually all clinical and preclinical research. It is found predominantly in fresh Polygonum cuspidatum root extract and freshly produced red grape skin. It is the form referenced in the Howitz et al. and Baur et al. studies.

Cis-resveratrol is the less stable isomer and is not the reference form used in published human trials. Trans-resveratrol converts to cis-resveratrol on exposure to UV light, heat, and time — which is why storage conditions matter. Keep resveratrol in a cool, dark place with the lid closed. Swanson's Higher Potency formula uses Polygonum cuspidatum root extract, which at manufacture is high in trans-resveratrol.

A second bioavailability consideration is absorption rate. Resveratrol is rapidly metabolised in the gut and liver — oral bioavailability of free resveratrol is relatively low, with peak plasma concentrations reached within 30–60 minutes and rapid clearance. Taking resveratrol with a meal is recommended for tolerability and may support absorption.

Taking Resveratrol with Food

Taking resveratrol with a meal is recommended for tolerability. Some longevity researchers, including David Sinclair (Harvard Medical School), have publicly noted taking resveratrol with a fat-containing food such as full-fat yoghurt — on the basis that fat may slow gastric emptying and support absorption. This is anecdotal practice, not an RCT-validated protocol. The Swanson label directs: take with a meal.

Food Sources

Resveratrol in Food vs Supplements

The French Paradox observation — low rates of cardiovascular disease in French populations despite high saturated fat intake — was linked to red wine consumption and, subsequently, to resveratrol. The hypothesis attracted significant research funding through the 1990s and 2000s. It is worth understanding what it actually implies for supplementation.

Source Resveratrol Content Notes
Polygonum cuspidatum root extract Very high — varies by extract concentration Primary commercial supplement source
Red grape skin (fresh) 0.24–1.25 mg per 100g Concentration varies by variety and climate
Red wine 0.1–2 mg per 150ml glass Fermentation and storage reduce concentration
Blueberries ~0.03 mg per 100g Low concentration, high in other polyphenols
Peanuts ~0.01 mg per 100g Negligible
Swanson Resveratrol 250mg (supplement) 250mg per capsule 125–2,500× the amount in a glass of red wine

The practical implication is straightforward. You cannot consume clinically studied doses of resveratrol from food alone — certainly not without simultaneously consuming alcohol in quantities that cause far greater harm than resveratrol provides benefit. Supplementation is the only practical route to the 150–500 mg doses used in human clinical research.

Clinical Evidence

Clinical Evidence: What Human Trials Show

The human clinical trial record for resveratrol is mixed — which is the honest assessment. There are positive findings in specific populations and endpoints, conflicting findings in others, and a persistent gap between the impressive preclinical data and the more modest human results.

Preclinical — Foundational
Baur et al. 2006 (Nature) — Resveratrol improves health and survival in obese mice

Baur JA, Pearson KJ, Price NL, and Sinclair DA (Harvard Medical School) published results showing resveratrol (22 mg/kg/day) significantly improved insulin sensitivity, reduced liver pathology, and extended survival in obese mice on a high-calorie diet. Mitochondrial biogenesis via SIRT1/PGC-1α pathway was documented. This study is foundational to the longevity narrative for resveratrol. However, it is a mouse study — and the dose used was proportionally much higher than the 250mg doses studied in human trials. Human translation remains unconfirmed.

Baur JA et al. Nature. 2006;444(7117):337-342 — PubMed 17086191[2]

RCT — Positive
Bhatt et al. 2012 — Improved glycaemic control in type 2 diabetes

Bhatt JK, Thomas S, and Nanjan MJ conducted a randomised controlled trial in 62 patients with type 2 diabetes mellitus. Participants received resveratrol (250mg/day) or placebo alongside standard antidiabetic treatment for 3 months. The resveratrol group showed significant improvements in fasting blood glucose (p<0.05), HbA1c (p<0.01), insulin sensitivity (p<0.05), and systolic blood pressure (p<0.05). No significant adverse effects. This is one of the better-designed positive human RCTs for resveratrol at a 250mg dose — directly relevant to the Swanson product dose.

Bhatt JK et al. Nutrition Research. 2012;32(7):537-541 — PubMed 22901562[3]

RCT — Positive
Witte et al. 2014 — Memory performance and hippocampal connectivity in older adults

Witte AV, Kerti L, Margulies DS, and Flöel A (Charité — Universitätsmedizin Berlin) conducted a double-blind RCT in 46 healthy overweight older adults (50–75 years). Resveratrol 200mg/day over 26 weeks significantly improved word retention scores (p<0.05), increased functional connectivity between hippocampal regions on fMRI, and improved glucose metabolism in the hippocampus. This trial is notable for demonstrating a cognitive endpoint in healthy older adults — not a disease population. Sample size is small; replication is needed.

Witte AV et al. Journal of Neuroscience. 2014;34(23):7862-7870 — PubMed 24899709[5]

RCT — Conflicting
Gliemann et al. 2013 — Resveratrol blunts exercise training benefits in older men

This is the most important conflicting trial in the resveratrol literature and is frequently omitted from supplement marketing. Gliemann L, Schmidt JF, Olesen J, and Hellsten Y (University of Copenhagen) tested resveratrol 250mg/day vs placebo alongside 8 weeks of high-intensity exercise training in 27 healthy older men. The placebo + exercise group showed significant improvements in VO₂max, blood pressure, and cardiovascular biomarkers. The resveratrol + exercise group showed significantly blunted or absent improvements in the same markers. The proposed mechanism: resveratrol's antioxidant activity reduced the reactive oxygen species that act as training signals in skeletal muscle. This trial has significant implications for active individuals considering resveratrol supplementation.

Gliemann L et al. Journal of Physiology. 2013;591(20):5047-5059 — PubMed 23878368[6]

Research Context — Not Product Claims

The clinical and mechanistic research discussed in this article relates to resveratrol as a studied compound. It should not be read as a claim that Swanson Resveratrol 250mg Higher Potency produces these effects. This product is a food supplement, not a medicine. No authorised EU health claim is currently made for resveratrol on this page or on the product.

Swanson Resveratrol 250mg Higher Potency

Polygonum cuspidatum root extract · 30 capsules · 30-day supply · Available in Ireland from Probiotic.ie

250mg per capsule Polygonum cuspidatum 30-day supply Gluten free · Non-GMO Swanson formula Next-day DPD delivery
Buy in Ireland — €17.95 →

Dispatched from Dublin · Nationwide Ireland delivery via DPD · Authorised Irish retailer for Swanson · FSAI-regulated food supplement · Not a medicine · SKU: SWU530

Cardiovascular Research

Resveratrol and Cardiovascular Health

The cardiovascular hypothesis for resveratrol — rooted in the French Paradox observation — has the most developed human clinical evidence base of any resveratrol research area. Results are mixed, but some positive signals exist at lower doses.

Magyar K, Halmosi R, Palfi A, and Tóth K (University of Pécs, Hungary) conducted an RCT in 40 patients with stable coronary artery disease. Participants received resveratrol 10mg/day or placebo for 3 months alongside standard cardiological treatment. The resveratrol group showed significant improvements in left ventricular diastolic function (p<0.05), flow-mediated dilation (FMD — a measure of endothelial function, p<0.05), and reduced LDL oxidation.[4] This is notable because a 10mg dose — far below most supplement doses — produced measurable effects.

On the other hand, the Gliemann et al. 2013 trial (discussed above) found resveratrol blunted cardiovascular adaptation to exercise in healthy older men. For active individuals, this conflicting data is material and should inform their decision.

Cardiovascular Conditions — Consult Your GP

Resveratrol has antiplatelet activity. Do not use resveratrol if you are taking anticoagulant or antiplatelet medication (warfarin, aspirin, clopidogrel) without explicit GP approval. The Magyar et al. trial was conducted in patients already receiving standard cardiac treatment — resveratrol was an adjunct, not a standalone intervention. Resveratrol is a food supplement and does not treat cardiovascular disease. Consult your GP for any cardiac health concern.

Longevity Stacks

Stacking Resveratrol: NMN, Pterostilbene and Quercetin

Resveratrol is increasingly discussed as part of a broader longevity supplement stack. The rationale for each combination is mechanistically grounded, even where clinical trial evidence for the combinations specifically is absent.

Resveratrol + NMN

This is the most discussed resveratrol combination in longevity research circles, largely due to David Sinclair's (Harvard Medical School) public commentary on his own protocol. The mechanistic logic is well-structured: think of NAD⁺ as the fuel and SIRT1 as the engine. Sirtuins require NAD⁺ to function — without sufficient NAD⁺, SIRT1 cannot perform its deacetylase activity regardless of any resveratrol-mediated modulation. NAD⁺ levels decline with age, which is why NMN (nicotinamide mononucleotide) — a direct NAD⁺ precursor — has attracted significant research interest alongside resveratrol. NMN provides the fuel; resveratrol is proposed to help run the engine.

Sinclair has publicly described taking both NMN and resveratrol daily as part of his personal longevity protocol, framing this fuel/engine relationship explicitly. No published RCT has tested the NMN and resveratrol combination for longevity outcomes in humans — the combination is mechanistically coherent but not clinically validated as a stack. Both are food supplements.

Resveratrol + Pterostilbene

Pterostilbene is a methylated analogue of resveratrol found in blueberries and grapes. It has greater oral bioavailability than resveratrol (approximately 80% vs <1% for free resveratrol in some pharmacokinetic studies) due to its increased lipophilicity and resistance to rapid metabolism. Some researchers propose combining both compounds to achieve complementary bioavailability profiles. Pterostilbene also activates SIRT1 and AMPK. Whether the combination produces synergistic effects beyond either alone has not been established in humans.

Resveratrol + Quercetin

Quercetin is a flavonoid with proposed senolytic activity — the ability to selectively clear senescent cells (cells that have stopped dividing but resist apoptosis and secrete pro-inflammatory factors). Combining resveratrol's SIRT1 activation with quercetin's proposed senolytic activity is theoretically appealing in the context of cellular ageing. Again, this is mechanistic reasoning — no human RCT has tested this specific combination for longevity endpoints.

Compound Proposed Mechanism Bioavailability Human RCT Evidence Stack Value
Resveratrol 250mg SIRT1 activation, AMPK, antioxidant, anti-inflammatory Low — rapid metabolism Yes — mixed, endpoint-specific Foundation compound
NMN NAD⁺ precursor — raises cellular NAD⁺ for sirtuin function Moderate — oral absorption documented Limited human data Complementary (NAD⁺ pathway)
Pterostilbene SIRT1/AMPK activation — resveratrol analogue, higher bioavailability Higher than resveratrol Very limited Complementary (bioavailability)
Quercetin Proposed senolytic — targets senescent cells; also antioxidant Moderate Emerging — small trials Theoretically complementary
Stack Caution

None of the above combinations have been tested for safety interactions in published clinical trials. If you are taking any prescription medication — particularly blood thinners, diabetes medication, or blood pressure drugs — consult your GP before combining multiple supplements. More compounds do not automatically mean more benefit. Start with one supplement, assess tolerability, then add others incrementally if appropriate.

Dosage

Resveratrol Dosage and How to Take It

Human clinical trials have used resveratrol doses ranging from 10mg to 2,000mg per day. The dose range studied is unusually wide, reflecting the diversity of research objectives — from cardiovascular markers at very low doses to Alzheimer's biomarkers at very high doses.

Study Daily Dose Duration Population Primary Outcome
Magyar et al. 2012 10mg 3 months Coronary artery disease Cardiac function ↑ (p<0.05)
Bhatt et al. 2012 250mg 3 months Type 2 diabetes HbA1c ↓, insulin sensitivity ↑ (p<0.01)
Witte et al. 2014 200mg 26 weeks Healthy older adults Memory retention ↑ (p<0.05)
Gliemann et al. 2013 250mg 8 weeks Healthy older men (exercising) Exercise adaptations blunted
Turner et al. 2015 500–2,000mg 52 weeks Mild–moderate Alzheimer's CSF biomarker changes; no cognitive improvement

Practical Dosage Guidance

The Swanson Resveratrol 250mg Higher Potency capsule matches the dose used in the Bhatt et al. 2012 (glycaemic control, 250mg) and Gliemann et al. 2013 (exercise/cardiovascular, 250mg) trials. Take one capsule per day with a meal, as directed on the label. Taking with food is recommended for tolerability and may support absorption.

Weeks 1–2
Adaptation period. Resveratrol does not produce acute, noticeable effects in most people. Gastrointestinal tolerance is usually established in the first two weeks — mild nausea at initiation, if any, typically resolves.
Weeks 4–8
Most human RCTs with positive metabolic outcomes ran for 3 months minimum. The Bhatt et al. 2012 trial saw significant HbA1c and insulin sensitivity improvements at the 3-month mark. Short trial periods may not be sufficient to see measurable effects.
Weeks 12–26
The Witte et al. cognitive trial ran for 26 weeks. Longer-term consistent use appears necessary for cognitive and neurological endpoints. If no benefit is perceived by 12 weeks, review dose, product quality, and whether timing with meals is optimal.
Long-Term Use
Resveratrol safety data at 250–500mg is available up to 12 months in published trials without serious adverse events. Data beyond 12 months is limited. Annual review of your supplement protocol with your GP is reasonable if using long-term alongside other medications.
Safety

Resveratrol Side Effects, Safety and Interactions

At doses up to 500mg per day, resveratrol has a reasonable tolerability profile in published clinical trials. At higher doses (1,000mg+), gastrointestinal side effects are more commonly reported. There are specific interaction risks that must be highlighted.

Population / Situation Guidance
Healthy adults (250mg/day) Generally well tolerated. Minor GI symptoms at initiation are possible.
Taking anticoagulants (warfarin, heparin) Do not combine. Resveratrol has antiplatelet activity and may potentiate bleeding risk.
Taking antiplatelet drugs (aspirin, clopidogrel) Consult GP before use. Additive antiplatelet effect is pharmacologically plausible.
Taking diabetes medication (metformin, insulin) Consult GP. Resveratrol may affect blood glucose — additive effect possible. Monitor glucose.
Oestrogen-sensitive conditions (breast, uterine cancer history) Consult oncologist. Resveratrol has phytoestrogen-like activity. Not suitable without medical guidance.
Pregnant or breastfeeding Do not use. No safety data. Resveratrol crosses placental barrier in animal studies.
Active exercise training (competitive athletes) Consider the Gliemann et al. 2013 finding carefully. Resveratrol may blunt training adaptations.
Under 18 years Not intended for use by individuals under 18 years.
Oestrogen-Sensitive Conditions

Resveratrol acts as a phytoestrogen — it can bind to oestrogen receptors and modulate oestrogen signalling. In some studies it has shown anti-oestrogenic effects; in others, pro-oestrogenic. This bidirectional activity is not fully characterised. Anyone with a personal or family history of oestrogen receptor-positive cancers (breast, uterine, ovarian) should consult their oncologist before taking resveratrol.

Buying Guide — Ireland

Where to Buy Resveratrol in Ireland

Resveratrol supplements are available in Ireland from pharmacies, health food stores, and online. Key differences between products are source (Polygonum cuspidatum vs grape skin), dose, and whether the product specifies trans-resveratrol.

Product Dose Source Capsules Available Ireland
Swanson Resveratrol 250mg Higher Potency 250mg Polygonum cuspidatum root extract 30 caps Yes — Probiotic.ie €17.95 · Authorised Irish retailer
Solgar Resveratrol 100mg 100mg Polygonum cuspidatum + grape extract 60 caps Selected health stores
Jarrow Resveratrol 100mg 100mg Polygonum cuspidatum 60 caps Online import
NOW Foods Resveratrol 200mg 200mg Polygonum cuspidatum 60 caps Selected online

Swanson Resveratrol 250mg Higher Potency (SKU: SWU530) is available from Probiotic.ie at €17.95 for 30 capsules — a 30-day supply at one capsule daily. At 250mg per capsule from Polygonum cuspidatum root extract, this is among the highest-dose single-capsule daily serving options available from an Irish retailer. Orders ship from our Dublin warehouse with next-day DPD tracked delivery across Ireland.

Product Details Verified

Product details on this page — including dose (250mg per capsule), capsule count (30), source (Polygonum cuspidatum root extract), SKU (SWU530), and price (€17.95) — were verified by Probiotic.ie from current Swanson packaging and supplier information. Product details should always be checked against the current label before use, as formulations and pricing may change.

Irish Delivery

All Swanson Resveratrol orders placed via Probiotic.ie are dispatched from our Dublin warehouse. Standard next-day tracked delivery via DPD across all of Ireland. No import delays, no customs duties. Probiotic.ie is an authorised Irish retailer for Swanson and operates under FSAI food supplement regulations.

Research Context — Not Product Claims

The clinical research discussed in this guide relates to resveratrol as a studied compound. It should not be read as a claim that any supplement product produces these effects. Swanson Resveratrol 250mg Higher Potency is a food supplement, not a medicine. No authorised EU health claim is made for resveratrol.

Swanson Resveratrol 250mg Higher Potency — Buy in Ireland

Polygonum cuspidatum root extract · 30 capsules · 30-day supply · €17.95 · Ships from Dublin

250mg per capsule Polygonum cuspidatum Gluten free · Non-GMO Swanson formula Nationwide Ireland delivery SKU: SWU530
Order Now — €17.95 →

Authorised Irish retailer for Swanson · Dispatched from Dublin · FSAI-regulated food supplement · Not a medicine · Not intended to diagnose, treat, cure, or prevent any disease

FAQ

Frequently Asked Questions

What is resveratrol and what is it used for?

Resveratrol is a polyphenol compound found in Polygonum cuspidatum (Japanese knotweed) root, grape skins, and certain berries. It has been studied for its antioxidant properties, proposed modulation of SIRT1 (Sirtuin-1) — a NAD⁺-dependent deacetylase linked to cellular ageing pathways — and associations with cardiovascular and metabolic markers in selected clinical trials. In Ireland, resveratrol is a food supplement classified under FSAI regulations — it is not a medicine and does not treat any medical condition.

How does resveratrol interact with SIRT1 and NAD⁺ pathways?

Resveratrol is proposed to modulate SIRT1 (Sirtuin-1), a NAD⁺-dependent deacetylase involved in DNA repair, metabolic regulation, and cellular stress response. Howitz et al. (Nature, 2003) first identified resveratrol as a compound with SIRT1-modulating properties. Baur et al. (Nature, 2006) showed it improved health markers and survival in obese mice. Whether SIRT1 modulation by resveratrol produces meaningful longevity outcomes in humans remains an open research question — most longevity data is preclinical.

What is the difference between trans-resveratrol and cis-resveratrol?

Trans-resveratrol is the more stable isomer and the form studied in clinical and preclinical research. Cis-resveratrol is less stable and not the reference form used in published human trials. Trans-resveratrol converts to cis-resveratrol on exposure to UV light and heat. Quality resveratrol supplements use Polygonum cuspidatum root extract — the highest-concentration natural source of trans-resveratrol. Store resveratrol supplements in a cool, dark place and replace the cap after use.

What is the correct resveratrol dosage?

Human RCTs have used doses from 10mg (Magyar et al. cardiac trial) to 2,000mg (Turner et al. Alzheimer's trial). Most studies with positive metabolic and cognitive outcomes used 150–500mg daily. Swanson Resveratrol 250mg Higher Potency delivers 250mg per capsule — take one capsule daily with a meal. This dose matches those used in the Bhatt et al. 2012 (glycaemic control) and Gliemann et al. 2013 (cardiovascular exercise) trials. Do not exceed the stated dose. Consult your GP if on any medication.

Can I stack resveratrol with NMN?

Resveratrol and NMN (nicotinamide mononucleotide) target related parts of the sirtuin pathway: NMN raises cellular NAD⁺ (which sirtuins require to function), while resveratrol is proposed to modulate SIRT1. David Sinclair (Harvard Medical School) has publicly discussed taking both compounds as part of his personal protocol. No RCT has tested this combination for longevity outcomes in humans. Both are food supplements. Consult your GP before combining, especially if on any prescribed medication.

What are the side effects of resveratrol?

At 250–500mg daily, resveratrol has generally been well tolerated in clinical trials. Possible mild side effects include nausea and loose stools at initiation, particularly if taken without food. At doses above 1,000mg, GI symptoms are more frequent. Resveratrol has antiplatelet activity — it should not be combined with blood-thinning medications without medical advice. It is not suitable during pregnancy or breastfeeding. Those with oestrogen-sensitive conditions should consult their GP or oncologist before use.

Does resveratrol actually extend human lifespan?

No published human clinical trial has demonstrated that resveratrol extends human lifespan. Lifespan extension by resveratrol has been shown in yeast (Howitz et al. 2003), fruit flies, nematodes, and obese mice (Baur et al. 2006). Human trials have examined specific biomarkers — cardiovascular, metabolic, cognitive — not lifespan. Resveratrol's role in human longevity is a well-grounded biological hypothesis, not an established clinical finding. No supplement product can make longevity claims under FSAI guidelines.

Is resveratrol good for the heart?

Magyar et al. 2012 found that 10mg resveratrol daily improved cardiac diastolic function and reduced LDL oxidation in coronary artery disease patients over 3 months (p<0.05). However, Gliemann et al. 2013 found resveratrol at 250mg blunted the cardiovascular benefits of exercise training in healthy older men. For those relying on exercise as their primary cardiovascular intervention, this is a significant conflicting finding. Resveratrol is a food supplement and does not treat cardiovascular disease. Consult your GP for cardiac health management.

Can I take resveratrol with blood thinners?

No — not without explicit GP approval. Resveratrol has documented antiplatelet activity and may interact with anticoagulant medications including warfarin, heparin, and antiplatelet drugs such as aspirin (at blood-thinning doses) and clopidogrel. The combined effect on bleeding risk is pharmacologically plausible but not quantified in formal drug interaction studies. Do not combine resveratrol with blood-thinning medication unless your GP or pharmacist has explicitly advised that it is appropriate for your situation.

Where can I buy resveratrol in Ireland?

Swanson Resveratrol 250mg Higher Potency (SKU: SWU530) — 30 capsules sourced from Polygonum cuspidatum root extract — is available from Probiotic.ie at €17.95 per pack. Probiotic.ie is an Irish supplement retailer based in Dublin with next-day tracked DPD delivery across Ireland. Resveratrol is also available in some Irish pharmacies and health food stores, typically at lower doses (50–100mg). Probiotic.ie is an authorised Irish retailer for Swanson and operates under FSAI food supplement regulations.

DG
Darren Grant — Founder, Probiotic.ie

Darren Grant is the Managing Director of TenX Tech Ltd and founder of Probiotic.ie, Ireland's specialist retailer for clinically formulated probiotics and quality food supplements. He holds authorised exclusive distribution rights for CDS22-formula (the original De Simone Formulation) in Ireland and the UK, and has over a decade of experience in supplement distribution, formulation analysis, and regulatory compliance. Content on Probiotic.ie is written to FSAI and HPRA standards and cites published research to support accuracy and balance.

This guide is for educational purposes only and does not constitute medical advice. Swanson Resveratrol 250mg Higher Potency is a food supplement regulated under FSAI guidelines and is not intended to diagnose, treat, cure, or prevent any disease or medical condition. If you have persistent or worsening symptoms, or any concern about your health, consult a GP or relevant specialist. Probiotic.ie is regulated under FSAI food supplement guidelines. Not a medicine.

Sources
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