01 — Evidence
Evidence Summary
Resveratrol has one of the broadest preclinical anti-cancer signatures of any dietary polyphenol and one of the widest gaps between that signature and what an oral dose delivers to the body. The three tiers below should be read together: the laboratory tier is deep, the animal tier is broad and partly oral, and the human tier is small, mechanistic, and concentrated in the gut — the one place an oral dose reaches high concentration.
Human
Biomarker Signal, Gut-Localized
Pharmacodynamic change; no positive efficacy
In colorectal-cancer patients, short pre-surgery dosing reached the bowel lining and modestly lowered a tumor-proliferation marker; a micronized form raised an apoptosis marker in liver-metastasis tissue. No study shows tumor shrinkage or longer survival.
Animal
Broad and Partly Oral
Reproduced across tumor types, but genuinely mixed
Oral resveratrol reduced colon, prostate, cervical, and liver tumors or their spread in animals, tied to lower growth signaling and more apoptosis. The picture is not uniform — one careful colon study found no effect at all.
In Vitro
Mechanism-Rich, High-Dose
Effects sit above achievable blood levels
In cultured cancer cells resveratrol has been reported to suppress AKT–mTOR, STAT3, and Wnt signaling and trigger mitochondrial apoptosis — but at concentrations far above what an oral dose reaches in the bloodstream.
Human
Clinical Record
The human record is small, mechanistic, and — tellingly — concentrated in the gastrointestinal tract, the one compartment an oral dose demonstrably saturates. In 20 colorectal-cancer patients, eight daily doses of resveratrol before surgery reached colorectal tissue at appreciable concentration and reduced the proliferation marker Ki-67 by a modest 5%.[1] In colorectal-cancer patients with liver metastases, micronized resveratrol (SRT501) reached hepatic tissue and raised the apoptosis marker cleaved caspase-3 by 39% in malignant tissue versus placebo.[2]
Continue reading — full research detail+
A phase I pilot in colon-cancer patients drew the sharpest line in the data: resveratrol did not inhibit the Wnt pathway in the tumor tissue itself, but significantly reduced Wnt target-gene expression in the adjacent normal colonic mucosa — a chemopreventive direction of effect, not a therapeutic one against established tumor.[3] Beyond the gut, a repeat-dose study in 40 healthy volunteers found resveratrol lowered circulating IGF-I and IGFBP-3, a proposed chemopreventive mechanism in people without cancer,[4] and a randomized trial in 39 women at increased breast-cancer risk found decreasing RASSF-1α promoter methylation as serum resveratrol rose.[5] The one human trial designed to read out tumor response — a phase 2 study of high-dose micronized resveratrol (SRT501, 5 g/day) in 24 patients with relapsed multiple myeloma — reported an intention-to-treat response rate of only 8% and was halted early after five patients developed renal failure.[30] So the human record lacks any controlled evidence of tumor response, delayed progression, or improved survival — the tumor-directed studies are biomarker or pharmacodynamic readouts, and the one response-based trial was negative.
Signal maturity: there are several small human pharmacodynamic signals, not yet independently validated, and each is a marker change at a site of high local exposure, not a demonstration that resveratrol changes the course of disease. It establishes that the compound is bioactive in human tissue where it can reach — chiefly the gut — and should be read as hypothesis-generating for chemoprevention, not as anti-tumor efficacy.
Animal
Preclinical Signal
The tumor-directed case is strongest here and, unusually for a polyphenol, is often produced by oral dosing. In Apc-Min mice, dietary resveratrol reduced intestinal adenomas with a striking nonlinear dose response — a very low dose cut adenoma number by about 40% and outperformed a 200-fold higher one — an effect tracking AMPK activation and reduced mTOR signaling, and reproduced as enhanced AMPK signaling in human ex-vivo colorectal tissue.[6] Oral resveratrol also reduced carcinogen-induced colon aberrant crypt foci by roughly a third while raising pro-apoptotic Bax,[7] and cut small-intestinal tumors by 70% in Min mice with lower Wnt-target cyclins.[8]
Continue reading — full research detail+
The picture is honestly mixed: a well-conducted study found dietary resveratrol did not change intestinal tumor load in Apc-Min mice despite reaching the tumors and lowering PGE2 — direct counter-evidence held alongside the positive results.[9] Across other tumor types, oral resveratrol shrank a cervical xenograft by inactivating STAT3 at Tyr705,[10] and reduced prostate-xenograft growth and lung metastasis with lower phospho-Akt and miR-21.[11] In a hepatocellular xenograft it inhibited NF-κB and lowered VEGF and microvessel density.[12] Doses and routes vary, and some studies did not state the administration route — a limit on how far they translate to an oral dose.
Signal maturity: the animal evidence is broad, mechanistically coherent, and partly oral, which is what lifts resveratrol above a purely in-vitro story. But it includes a frank negative, several route-unspecified studies, and administered doses whose systemic exposure is itself the open question the Pharmacokinetics section takes up. No animal result substitutes for a controlled human outcome.
In Vitro
Cell Model Data
Almost all of resveratrol's mechanistic depth lives here, and almost all of it at concentrations above what an oral dose reaches in plasma. Resveratrol has been reported to inhibit Src-driven STAT3 signaling and repress cyclin D1, Bcl-xL, and Mcl-1, selectively killing cells that depend on activated STAT3;[13] it has been reported to cause S-phase arrest and lower cyclin D1 and β-catenin in colon cells at a growth-inhibitory concentration around 70–150 µmol/L;[14] and one primary source states plainly that its Wnt inhibition is "ineffective at concentrations less than 10 µM."[15]
Continue reading — full research detail+
Resveratrol has been reported to drive the complete intrinsic apoptotic cascade in prostate cells at 20 µmol/L — Bax and Bak up, Bcl-2 and survivin down, cytochrome-c release, caspase-9 and -3 activation — without harming normal prostate cells,[16] and at 25 µmol/L a distinct copper-mobilizing, ROS-dependent pro-oxidant mechanism (abolished by a copper chelator and by ROS scavengers) contributed a second route to cell death, illustrating its antioxidant-at-low, pro-oxidant-at-high duality.[17] It has also been reported to p53-independently sensitize diverse tumor cells, but not normal fibroblasts, to TRAIL-induced apoptosis by depleting survivin,[18] suppress AKT/mTOR while inducing ER stress in colorectal cells at 50–200 µmol/L,[19] inhibit the pentose phosphate pathway,[20] and induce autophagy in glioma cells.[21] Its reported SIRT1 activation — an early claim later contested for native substrates — sits alongside the metabolic (AMPK) arm rather than cleanly explaining it.[22]
Signal maturity: the cell data establish a rich, multi-target mechanism, but almost every effect requires 10–200 µmol/L, whereas an oral dose produces sub-micromolar parent resveratrol in plasma. Read every cell-level effect through the Pharmacokinetics and Administration section below, where that gap is quantified.
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02 — Pathways
Pathway Interaction Profile
Resveratrol touches an unusually wide range of cancer pathways, but every tumor-directed role is read as partial for one reason: the concentrations that drive these mechanisms in the laboratory are far above the level an oral dose reaches in the bloodstream. The roles below are ordered by the strength and directness of their evidence, and each is caveated by that exposure gap.
Resveratrol's Contain evidence is the suppression of the inflammatory and angiogenic signals a tumor recruits to build a supportive niche — lower NF-κB activity and reduced VEGF-driven blood-vessel growth in animal tumors. It is read as partial because those effects, though shown in living tumors, depend on exposures the concentration gap makes uncertain in people.
Block Seeding & Niche Formation
Research concerning formation of supportive pre-metastatic niches at distant sites.
NF-κB / TNF-α / IL-6 inflammatory axis
In a hepatocellular-carcinoma xenograft, resveratrol intensely inhibited NF-κB activation, which the same study linked mechanistically to the fall in VEGF and the reduced tumor vascularity.[12] NF-κB suppression is one of resveratrol's most consistently reported actions across cell systems; this is its load-bearing in-vivo tumor demonstration.
Angiogenesis / VEGF / HIF-1α
Resveratrol lowered VEGF protein and mRNA and reduced microvessel density in a hepatocellular xenograft, mechanistically tied to suppressed NF-κB in the same model.[12] Anti-angiogenic in vivo, but at exposures the Pharmacokinetics section flags as unreachable systemically in humans.
This is resveratrol's deepest tumor-directed role: suppression of the AKT–mTOR, STAT3, and Wnt proliferative programs, corroborated in oral animal models and — for the AMPK–mTOR axis — in human ex-vivo tissue. It is read as partial because the effective concentrations are largely above achievable plasma levels, and because the Wnt evidence is genuinely mixed, including a negative animal study.
Expansion Suppression
Research concerning proliferation, cell-cycle progression, and the capacity of lesions to add durable mass.
PI3K–AKT–mTOR (signaling)
The best-corroborated Weaken node. Dietary resveratrol reduced Apc-Min intestinal adenomas through AMPK activation and lower phospho-mTOR, 4EBP1, and S6K — with the AMPK effect reproduced in human ex-vivo colorectal tissue, and a notable nonlinear dose response in which a very low dose outperformed a 200-fold higher one.[6] Oral resveratrol also reduced prostate-xenograft growth and lung metastasis with lower phospho-Akt,[11] and suppressed AKT and mTOR signaling in colorectal cells.[19] Resveratrol's reported (and now debated) SIRT1 activation is associated with this metabolic axis, though the in-vivo effect above rests on AMPK, not on SIRT1.[22]
JAK/STAT (STAT3)
Oral (intragastric) resveratrol shrank a cervical (HeLa) xenograft by inactivating STAT3 phosphorylation specifically at Tyr705, with downstream loss of EMT markers and matrix-degrading enzymes.[10] Mechanistically, resveratrol has been reported to block Src-driven constitutive STAT3 activation and repress the STAT3 targets cyclin D1, Bcl-xL, and Mcl-1, selectively killing STAT3-dependent cancer cells.[13]
Wnt / β-catenin
The mixed node, presented with its own counter-evidence. Oral resveratrol lowered the Wnt targets cyclin D1 and D2 in Min-mouse intestine,[8] and reduced β-catenin and cyclin D1 in colon-cancer cells.[14] But its Wnt inhibition is "ineffective at concentrations less than 10 µM,"[15] the one human study found the effect in normal mucosa rather than tumor,[3] and a separate Apc-Min study found no change in tumor load at all.[9] The evidence supports a Wnt interaction, not a reliable tumor-directed one at achievable exposure.
Resveratrol has been reported to push cancer cells into mitochondrial (intrinsic) apoptosis, shown both in animal tumors and in cultured cells, with a secondary copper-dependent pro-oxidant route and a death-receptor–sensitizing effect. It is read as partial because the pro-apoptotic concentrations sit above plausible oral plasma levels.
Direct Tumor-Directed Killing
Research concerning regulated tumour-cell death (apoptosis, ferroptosis, necroptosis).
Intrinsic apoptosis (mitochondrial / Bcl-2)
Oral resveratrol raised pro-apoptotic Bax in colon aberrant crypt foci in vivo.[7] In cultured prostate cells at 20 µmol/L it drove the complete cascade — Bax, Bak, PUMA, Noxa and Bim up, Bcl-2, Bcl-xL, survivin and XIAP down, mitochondrial cytochrome-c and Smac release, caspase-9 and -3 activation — without harming normal prostate cells;[16] at 25 µmol/L a distinct copper-mobilizing, ROS-dependent route (abolished by a copper chelator and ROS scavengers) added a second apoptotic mechanism.[17]
Extrinsic apoptosis (death receptors)
Resveratrol has been reported to p53-independently sensitize a range of tumor cells — but not normal fibroblasts — to TRAIL-induced apoptosis, by inducing p21-driven G1 arrest and depleting the apoptosis inhibitor survivin, engaging both death-receptor and mitochondrial signaling.[18] A sensitizing rather than standalone-killing effect.
Resveratrol's Protect classification is preclinical and supportive-care-shaped: it rests on animal evidence that resveratrol improves how chemotherapy performs and is tolerated, not on host-outcome human trials, so it carries a cited Oncology Host-Status summary rather than pathway cards. It is read as partial because the host benefit is real but demonstrated only in animals — and, in one respect, is double-edged.
Oncology Host-Status
Chemotherapy-combination (chemosensitization) — preclinical — resveratrol restored gemcitabine sensitivity and reversed a gemcitabine-induced cancer-stem-cell phenotype in pancreatic-cancer cells and a transgenic mouse model, acting by suppressing lipid synthesis through SREBP1;[26] in breast-cancer models it enhanced cisplatin's effect by inhibiting IL-6/STAT3 and repolarizing tumor-associated macrophages toward the M1 state, with the combination suppressing tumor growth more than cisplatin alone in vivo.[27]
Chemotherapy-toxicity reduction — preclinical — resveratrol attenuated doxorubicin-induced cardiotoxicity in rats, restoring cardiac function and lowering serum LDH and CK-MB, by upregulating VEGF-B; silencing VEGF-B abolished the protection.[28] This used non-tumor-bearing rats, so it shows organ protection rather than a whole-patient effect.
The dual-effect caveat — a review of resveratrol chemosensitization documents broad synergy across tumor types and drugs, but also flags that in some cells resveratrol suppressed the apoptosis induced by paclitaxel, vincristine, or daunorubicin — so the combination direction is drug-dependent, not uniformly favorable, and is a matter for the treating team rather than self-directed pairing.[29]
Scope — every finding here is preclinical (cell and animal models); no human host-outcome trial has tested it.
Block Seeding & Niche Formation
Research concerning formation of supportive pre-metastatic niches at distant sites.
In animal tumors resveratrol lowered VEGF and blood-vessel density, linked to suppressed NF-κB — reducing the inflammatory and vascular support a tumor recruits.
Expansion Suppression
Research concerning proliferation, cell-cycle progression, and the capacity of lesions to add durable mass.
The best-corroborated node: oral resveratrol reduced intestinal tumors in mice through AMPK activation and lower mTOR signaling, an effect echoed in human colorectal tissue.
Oral resveratrol shrank a cervical tumor in mice by shutting down STAT3 activation, a survival and inflammation hub.
Direct Tumor-Directed Killing
Research concerning regulated tumour-cell death (apoptosis, ferroptosis, necroptosis).
Intrinsic apoptosis (mitochondrial / Bcl-2)
Resveratrol has been reported to shift the Bax-to-Bcl-2 balance and trigger the mitochondrial death cascade in cancer cells and animal tumors — though at concentrations above what an oral dose reaches.
Oncology Host-Status
Human evidence on treatment-associated symptoms, tolerability, nutritional status, cachexia, chemoprevention, and chemotherapy-combination outcomes.
Chemotherapy-combination & toxicity (preclinical)
In animal models resveratrol made chemotherapy work better (restoring gemcitabine and cisplatin sensitivity) and eased one of its toxicities (doxorubicin heart damage) — though the same literature shows it can blunt some chemotherapy in certain cells, so the direction is drug-dependent.
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03 — Pharmacokinetics
Pharmacokinetics and Administration
This section is the key to the whole profile. Oral resveratrol is well absorbed but almost entirely converted to sulfate and glucuronide conjugates before it reaches the circulation, so the level of parent compound in blood is one to two orders of magnitude below what most of its mechanisms require — with the gut lining the clear exception. Those conjugates are not necessarily inert: some can regenerate parent resveratrol inside cells.
Absorption
Oral resveratrol is well absorbed — at least 70% of a dose — but rapid gut and liver conjugation means unchanged parent compound in blood stays below ~5 ng/mL.
The Concentration Gap
Even a 5 g dose peaks near 2.4 µmol/L of parent, while the lab effects need roughly 10–200 µmol/L. The exception is the gut lining, where local levels run high.
Clinical Dose Context
Human studies used 0.5–5 g/day, all achievable with retail products; gastrointestinal tolerability, not a blood ceiling, is the practical limit above ~2.5 g.
Formulation Effects
Micronized resveratrol (SRT501) raised plasma levels about 3.6-fold over standard powder — narrowing, but not closing, the concentration gap.
Metabolism
Rapid sulfation and glucuronidation dominate; conjugate levels exceed the parent by up to 20-fold; total resveratrol-related material shows a terminal half-life near 9 hours, while parent itself declines faster.
Co-Dosing Considerations
Resveratrol modulates several CYP enzymes (inhibiting CYP3A4, 2C9, 2D6; inducing 1A2), so it can shift the levels of co-taken medications.
Absorption
Oral resveratrol is efficiently taken up — a radiolabeled study found at least 70% of a 25 mg dose absorbed — but this high absorption does not translate into systemic exposure to the active parent compound. Peak plasma of resveratrol plus its metabolites reached about 491 ng/mL (~2 µmol/L) with a plasma half-life near 9 hours, yet unchanged parent resveratrol stayed below roughly 5 ng/mL.[23] The rate-limiting step is extremely rapid intestinal and hepatic conjugation — sulfation and glucuronidation — which strips the parent compound out of circulation almost as fast as it is absorbed.
The Concentration Gap
This is the fact that governs every role rating on this page. Even a single 5 g dose peaks at only about 539 ng/mL (2.4 µmol/L) of parent resveratrol,[24] while the mechanistic effects catalogued in Pathways require roughly 10–200 µmol/L in cell culture,[14,16,19] and one primary source states resveratrol is "ineffective at concentrations less than 10 µM" for the Wnt axis.[15] For conventional oral resveratrol the achievable parent concentration is therefore one to two orders of magnitude below most of the effective in-vitro range, though enhanced formulations narrow the gap (see Formulation Effects). The clear exception is the gut and colorectal mucosa, where an oral dose produces high local tissue concentration — a mean of 674 nmol/g in normal right-sided colorectal tissue at 1 g/day, with tumor tissue lower and highly variable (mean about 94 nmol/g)[1] — which is why the human pharmacodynamic signal is a colorectal one.
| Setting | Concentration | Interpretation |
|---|---|---|
| Parent resveratrol in plasma, single 5 g dose | 2.4 µmol/L | Mean peak after 5 g of conventional (non-micronized) resveratrol[24] |
| Unchanged parent, single 25 mg dose | <5 ng/mL | Most circulating drug is conjugate; some may regenerate parent in tissue[23] |
| Effective range in cell studies | 10–200 µmol/L | Above achievable plasma; "ineffective below 10 µM" for Wnt[14,15,16,19] |
| Normal colorectal mucosa, 1 g/day oral | 674 nmol/g | The exception — high local gut exposure; tumor tissue lower/variable (~94)[1] |
Clinical Dose Context
Human oncology and chemoprevention studies used oral doses from 0.5 to 5 g per day, all achievable with standard retail formulations. The colorectal-cancer pharmacodynamic studies used 0.5–1.0 g/day,[1] while the SRT501 liver-metastasis study used 5 g/day.[2] Above about 2.5 g/day the practical limit is gastrointestinal tolerability rather than any plasma ceiling, since higher doses mainly generate more conjugate.[4]
Formulation Effects
Because parent bioavailability is the limiting factor, formulation is the main available lever. Micronized resveratrol (SRT501) produced mean plasma resveratrol of about 1,942 ng/mL after a single 5 g dose — roughly 3.6-fold higher than published equivalent doses of non-micronized resveratrol — and reached measurable hepatic-tissue levels.[2] Even so, this remains below the effective in-vitro range, so an enhanced formulation narrows the concentration gap without closing it — and results from a micronized product should not be read as applying to ordinary resveratrol powder.
Metabolism
Resveratrol undergoes rapid, extensive phase II conjugation to resveratrol-3-O-sulfate, resveratrol-3-O-glucuronide, and resveratrol-4′-O-glucuronide, whose combined plasma levels exceed the parent by up to about 20-fold;[4] gut bacteria also hydrogenate the stilbene double bond.[23] The biological activity of the conjugates is incompletely defined — tissue deconjugation back to the active parent has been proposed but not quantified at a tumor — so the contribution of metabolites versus parent compound at a target site remains an open question rather than an established mechanism.
Co-Dosing Considerations
Unlike a poorly absorbed fiber, resveratrol is a clinically relevant modulator of drug-metabolizing enzymes, which is its main interaction concern. Each row is flagged by the most cautious guidance its cited evidence supports.
Discuss whether to combine, separate, or avoid Resveratrol and a medication with your treating oncology team or physician.
| Flag | Interaction |
|---|---|
| Avoid | High-dose micronized resveratrol (SRT501, gram-scale) during active cancer treatment without specialist oversight — a phase 2 study in 24 relapsed-myeloma patients was halted after five renal-failure events — which occurred during SRT501 monotherapy and were not seen once bortezomib was added, so the signal tracks high-dose resveratrol, not a bortezomib interaction.[30] Combining high-dose resveratrol with any chemotherapy belongs with the oncology team, not self-direction. |
| Caution | Drugs metabolized by CYP3A4, CYP2C9, or CYP2D6 — in a human study resveratrol inhibited all three, which can raise their blood levels; it instead induced CYP1A2, which can lower the levels of drugs that enzyme clears. Many oncology and cardiac drugs run through these enzymes.[32,33] |
| Caution | Anticoagulant or antiplatelet drugs, and the days before surgery — resveratrol inhibits thrombin-induced platelet aggregation in vitro (at ~6–12 µmol/L, above typical plasma levels), so clinically important bleeding is not established, but additive caution and disclosure to the surgical or oncology team are reasonable.[34] |
| Monitor | Hormone-sensitive conditions — resveratrol is a stilbene phytoestrogen with estrogen-receptor–modulating activity; its clinical significance in an oncology setting is uncharacterized, so awareness rather than a defined restriction is appropriate.[31] |
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04 — Onset & Washout
Onset and Washout
Resveratrol has a fast, well-characterized pharmacokinetic clock — quick absorption, a rapidly declining parent peak (total resveratrol-related material shows a terminal half-life of several hours), little accumulation — that should not be confused with a fast anti-tumor effect, because the parent-compound peak stays below the mechanistically active range.
Immediate Onset
Resveratrol reaches its plasma peak within about 1–2 hours; parent compound then declines quickly, while total resveratrol-related material shows a terminal half-life near 9 hours. But the parent-compound peak is far below the effective concentration, so a fast peak is not a fast tumor-directed effect.
Steady State
Because parent resveratrol clears within a day and does not meaningfully build up, consistent daily dosing — not a reservoir effect — is what sustained exposure in the studies.
Accumulated Effect
Human pharmacodynamic changes were observed with daily dosing over one to four weeks. That reflects how the markers are measured over time, not evidence that resveratrol must accumulate to act.
Dosing Pattern in Studies
Trials used steady daily oral dosing, typically 0.5–5 g/day over days to weeks. This describes how resveratrol was studied, not a recommended regimen.
Washout
How long resveratrol's influence takes to fade before it stops being a relevant factor.
No formal resveratrol washout interval is clinically established. Parent resveratrol clears rapidly, but how long its metabolite, platelet, and enzyme-modulating effects persist is not well characterized, and different formulations may behave differently. The more relevant timing consideration is its effect on drug-metabolizing enzymes, which begins as soon as use starts — so any washout decision before a procedure or a new medication defers to the treating team.
Two Distinct Clocks
Resveratrol runs on two timescales that are easy to conflate. The direct-pharmacology clock (Clock A) is fast: oral resveratrol is absorbed within 1–2 hours and peaks, after which parent compound declines quickly (the ~9-hour terminal half-life reported classically is for total resveratrol-related material, dominated by conjugates); it does not meaningfully accumulate.[23,24] The observed-effect clock (Clock B) is slower only because the human readouts — tissue proliferation markers, gene methylation — are measured after days to weeks of dosing.[1,2,5] The slow clock reflects the measurement interval, not a slow-building pharmacology; there is no evidence resveratrol must accumulate over weeks to act.
Steady State and Accumulation
Because of rapid clearance and conjugation, resveratrol reaches steady state quickly and accumulates little; repeat dosing raises conjugate levels more than parent-compound levels.[4,23] The consequence is that consistent daily intake, rather than any single large dose, is what maintained exposure in the trials — but even sustained dosing does not lift systemic parent resveratrol into the effective range described under Pharmacokinetics and Administration.
Dosing Pattern in Studies
The human studies used steady daily oral dosing — from 0.5–1.0 g/day in the colorectal pharmacodynamic trials to 5 g/day for the micronized formulation — over periods of days to a few weeks.[1,2,4] This describes how resveratrol was studied, not a recommended regimen.
Washout
No formal washout interval is clinically established for resveratrol. Parent resveratrol clears rapidly, but the persistence of its metabolite, platelet, and enzyme-modulating effects is not well characterized. The consideration that outlasts clearance is its modulation of CYP enzymes,[32] which is a reason to raise resveratrol use with the care team as soon as a new medication or procedure is planned, rather than to manage a fixed washout window.
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05 — Safety
Safety Profile
Resveratrol is generally well tolerated at commonly studied oral doses, with dose-dependent gastrointestinal upset as the routine adverse effect and one serious signal from a chemotherapy-combination trial.
Dose-dependent GI upset — the routine adverse effect: mild-to-moderate diarrhea, nausea, and abdominal pain appear mainly at daily doses of 2.5 g and above, and are the practical limit on dose.
Renal-toxicity signal at high-dose SRT501 — a phase 2 myeloma trial was halted after five renal-failure events during SRT501 monotherapy (not seen once bortezomib was added). The most serious human safety finding.
Phytoestrogen activity — resveratrol is a stilbene phytoestrogen with estrogen-receptor–modulating activity, a reasonable caution in hormone-sensitive settings, though no adverse estrogenic outcome was reported in the oncology trials.
Drug-metabolism interactions — resveratrol modulates several CYP enzymes; because this is an interaction rather than direct toxicity, it is detailed under Co-Dosing in Pharmacokinetics and Administration.
Heavy-metal contamination risk — Japanese knotweed, the main commercial resveratrol source, is a known accumulator of heavy metals such as cadmium, so knotweed-derived products warrant third-party heavy-metal testing. A product-quality caution, not an effect of resveratrol itself.
Bioenhancer (piperine) additives — some products add piperine to boost absorption; it sharply raises resveratrol exposure and carries its own enzyme interactions, changing the interaction profile. A formulation caution, not an effect of resveratrol itself.
Adverse Effects in Human Trials
Across the human studies, resveratrol's own adverse-effect profile is dominated by dose-dependent gastrointestinal upset. In the 40-volunteer repeat-dose study, the 2.5 g and 5 g daily doses caused mild-to-moderate diarrhea, nausea, and abdominal pain, while lower doses were well tolerated,[4] and a steady-state study of 2 g twice daily reported diarrhea in six of eight subjects[25] — gastrointestinal tolerability, not a plasma ceiling, is the practical dose-limiting factor.
The most serious human signal comes from high-dose micronized resveratrol: a phase 2 study of SRT501 (5 g/day) in 24 patients with relapsed or refractory multiple myeloma was halted after five serious renal-failure events, alongside frequent nausea (79%) and diarrhea (71%) and an intention-to-treat response rate of only 8%.[30] Tellingly, the renal failures occurred during SRT501 monotherapy and were not seen once bortezomib was added, so the signal tracks high-dose resveratrol in this population rather than a bortezomib interaction.
Resveratrol is also a stilbene phytoestrogen with estrogen-receptor–modulating activity, a reasonable caution in hormone-sensitive contexts even though no adverse estrogenic outcome was reported in the oncology trials.[31] Long-term safety and safety in pregnancy in an oncology population are not established. Its one meaningful drug-interaction consideration — modulation of CYP3A4, CYP2C9, CYP2D6, and CYP1A2 — is set out under Co-Dosing Considerations in Pharmacokinetics and Administration above rather than repeated here.[32,33]
A mechanistic bleeding caution rounds out resveratrol's own profile: it inhibits platelet aggregation in vitro, at concentrations above typical plasma levels,[34] so additive antiplatelet effects and the days before surgery are worth raising with the care team — although clinically important bleeding from oral resveratrol has not been established.
Product Quality and Formulation
These considerations sit outside resveratrol's own pharmacology but matter for an oncology buyer. Heavy-metal contamination: Japanese knotweed (Reynoutria / Polygonum japonica) — the main commercial resveratrol source — is a documented accumulator of heavy metals such as cadmium, reaching near-regulatory levels in plants grown on contaminated soil,[36] so knotweed-derived resveratrol warrants third-party heavy-metal and purity testing before use.
Bioenhancer additives: some products add piperine, which raises resveratrol exposure severalfold by blocking its glucuronidation[35] and itself inhibits drug-metabolizing enzymes — so a piperine-containing product both changes resveratrol's pharmacokinetics and compounds the CYP-interaction potential noted above. Neither is an adverse effect of resveratrol itself, but both are worth checking on a product label.
06 — Sourcing
Sourcing Guide
Because oral bioavailability is resveratrol's defining limitation, the characteristics that matter most are the trans-resveratrol content and whether a product uses an absorption-enhancing formulation. Our Sourcing Guide offers a curated list of products available on the retail market.
Resveratrol Sourcing Guide07 — Literature
References
Last reviewed: August 2026