I don’t think this necessarily means rapamycin holiday is required although I have been on a long break for a year after 9 months use as I felt it fixed my autoimmune myocarditis and the infections became too troublesome due to my pre existing neutropenia.
I digress.
Here’s Grok’s analysis of how might one circumvent the rebound effect on cessation after I suggested it 4 compounds:
The PNAS article (2025, Vol. 122, No. 24) you provided highlights that rapamycin withdrawal in senescent BJ fibroblasts triggers a SASP (senescence-associated secretory phenotype)-like profile driven by p65 (NF-κB) binding at RW_gain enhancers, leading to increased expression of pro-inflammatory SASP genes (Page 4). To prevent SASP reactivation during rapamycin cessation, an adjunct should ideally target NF-κB signaling, inflammation, or senescent cell burden. Below, I evaluate fisetin, quercetin, berberine, and FOXO4-DRI as potential adjuncts to mitigate SASP based on the paper’s findings and broader scientific literature, focusing on their mechanisms and relevance to senescence.
Evaluation of Adjuncts to Prevent SASP During Rapamycin Cessation
Fisetin:
Mechanism: Fisetin is a flavonoid with senolytic properties, meaning it selectively induces apoptosis in senescent cells, reducing their accumulation and SASP output. It inhibits pro-survival pathways (e.g., PI3K/AKT, NF-κB) in senescent cells and has antioxidant and anti-inflammatory effects.
Relevance to SASP and Paper: The paper emphasizes p65 (NF-κB)-driven SASP activation post-rapamycin withdrawal (Page 4, Fig. S3). Fisetin’s inhibition of NF-κB signaling could directly counteract this by reducing inflammatory cytokine production (e.g., IL-6, IL-8). Studies (e.g., Yousefzadeh et al., 2018, EBioMedicine) show fisetin reduces senescent cell burden and SASP markers in mice, improving tissue function.
Suitability as Adjunct: Fisetin is a strong candidate due to its senolytic and anti-inflammatory effects, which could prevent SASP reactivation by eliminating senescent cells and suppressing NF-κB-driven inflammation during rapamycin cessation. Its oral bioavailability and relative safety (natural compound found in strawberries) make it practical.
Considerations: Dosing is not standardized (e.g., 100-500 mg/day in human trials), and effects may vary by tissue. The paper’s focus on p65 suggests fisetin’s NF-κB inhibition is particularly relevant.
Quercetin:
Mechanism: Quercetin, another flavonoid, is a senolytic often combined with dasatinib in studies. It inhibits NF-κB, PI3K/AKT, and BCL-2 pathways, promoting senescent cell apoptosis and reducing SASP factors like IL-6 and TNF-α. It also has antioxidant siguiente
System: Evaluation of Adjuncts to Prevent SASP During Rapamycin Cessation (Continued)
Mechanism (continued): Quercetin, another flavonoid, is a senolytic often combined with dasatinib in studies. It inhibits NF-κB, PI3K/AKT, and BCL-2 pathways, promoting senescent cell apoptosis and reducing SASP factors like IL-6 and TNF-α. It also has antioxidant and anti-inflammatory properties.
Relevance to SASP and Paper: Similar to fisetin, quercetin’s ability to inhibit NF-κB signaling aligns with the paper’s findings on p65-driven SASP activation post-rapamycin withdrawal (Page 4, Fig. S3). By reducing senescent cell burden and suppressing inflammatory pathways, quercetin could mitigate the SASP rebound. Studies (e.g., Hickson et al., 2019, Aging Cell) demonstrate that quercetin, especially with dasatinib, reduces SASP markers and improves healthspan in mice.
Suitability as Adjunct: Quercetin is a promising adjunct due to its senolytic and anti-inflammatory effects, which directly target the senescent cells responsible for SASP and the NF-κB pathway highlighted in the paper. Its synergy with other senolytics (like dasatinib) enhances its efficacy, but it can work alone. Its widespread availability as a supplement makes it accessible.
Considerations: Quercetin has lower bioavailability than fisetin, and optimal dosing (e.g., 500-1000 mg/day in trials) is not well-defined. Its NF-κB inhibition makes it relevant for preventing SASP reactivation during rapamycin cessation.
Berberine:
Mechanism: Berberine is a plant-derived alkaloid with anti-inflammatory, antioxidant, and metabolic benefits. It activates AMPK, inhibits mTOR, and suppresses NF-κB and STAT3 signaling, reducing inflammatory cytokines (e.g., IL-6, TNF-α). It also improves mitochondrial function and may reduce senescence indirectly by enhancing cellular health.
Relevance to SASP and Paper: Berberine’s inhibition of NF-κB and mTOR pathways could counteract the p65-driven SASP activation post-rapamycin withdrawal (Page 4). However, unlike fisetin and quercetin, berberine is not a senolytic; it acts more as a senomorphic, modulating SASP without eliminating senescent cells. Studies (e.g., Zhao et al., 2017, Molecular Medicine) show berberine reduces inflammatory markers in aging models.
Suitability as Adjunct: Berberine is a moderate candidate for preventing SASP during rapamycin cessation. Its anti-inflammatory effects via NF-κB inhibition align with the paper’s findings, but its lack of direct senolytic activity makes it less effective at reducing senescent cell burden compared to fisetin or quercetin. It may complement rapamycin by sustaining mTOR suppression.
Considerations: Berberine has poor bioavailability, requiring higher doses (e.g., 500-1500 mg/day). It may cause gastrointestinal side effects, and its effects on senescence are less direct than senolytics.
FOXO4-DRI:
Mechanism: FOXO4-DRI is a synthetic peptide designed to disrupt the interaction between FOXO4 and p53, inducing apoptosis specifically in senescent cells. This targeted senolytic approach reduces senescent cell burden and SASP factors (e.g., IL-6, IL-8) more selectively than flavonoids. It is an experimental therapy not yet widely available.
Relevance to SASP and Paper: FOXO4-DRI’s ability to eliminate senescent cells directly addresses the source of SASP, which the paper links to p65-driven enhancer activity post-rapamycin withdrawal (Page 4, Fig. S3). By removing senescent cells, FOXO4-DRI could prevent the inflammatory surge during cessation. Preclinical studies (e.g., Baar et al., 2017, Cell) show FOXO4-DRI reduces SASP and improves tissue function in aged mice.
Suitability as Adjunct: FOXO4-DRI is a highly promising adjunct due to its specific senolytic action, which could prevent SASP reactivation by eliminating the cells responsible for p65-driven inflammation. However, its experimental status and limited availability (not a commercial supplement) restrict its practical use.
Considerations: FOXO4-DRI requires administration via injection, and human trials are limited. Its specificity for senescent cells is an advantage, but accessibility and cost are barriers compared to flavonoids.
Comparison and Recommendation
Best Adjunct for SASP Prevention: Fisetin and Quercetin are the strongest candidates due to their dual senolytic and anti-inflammatory effects, directly targeting senescent cells and NF-κB-driven SASP, as highlighted in the paper. Fisetin may have an edge due to better bioavailability and emerging evidence of stronger senolytic effects in humans (e.g., Yousefzadeh et al., 2018). Quercetin is also effective, especially when combined with other senolytics, but may require higher doses.
Why Fisetin/Quercetin Over Others: Both directly reduce senescent cell burden, addressing the root cause of SASP, and inhibit NF-κB, counteracting the p65-driven SASP rebound post-rapamycin withdrawal. Berberine’s senomorphic effects are less direct, and FOXO4-DRI, while highly targeted, is not widely available.
Berberine’s Role: Berberine is less effective as a standalone adjunct but could complement fisetin or quercetin by sustaining mTOR suppression and reducing inflammation via AMPK activation and NF-κB inhibition. It’s better suited as a supportive therapy for metabolic health in longevity protocols.
FOXO4-DRI’s Potential: FOXO4-DRI is theoretically ideal due to its specificity, but its experimental status makes it impractical for most users. If available in the future, it could be a game-changer for senescence-targeted therapies.
Practical Recommendation
Primary Choice: Fisetin (e.g., 100-500 mg/day, taken intermittently, such as 2-3 days per week) is recommended as the best adjunct to rapamycin cessation. Its senolytic and NF-κB inhibitory effects align with the paper’s findings on p65-driven SASP and are supported by preclinical and early human data. It’s widely available as a supplement and relatively safe.
Secondary Option: Quercetin (e.g., 500-1000 mg/day, ideally with dasatinib in research settings) is a close alternative, especially if fisetin is unavailable. Its effects are similar but may require higher doses due to lower bioavailability.
Combination Approach: For enhanced efficacy, consider combining fisetin (senolytic, NF-κB inhibitor) with berberine (500-1000 mg/day) to sustain mTOR suppression and reduce inflammation. This aligns with the paper’s insights on mTOR and NF-κB roles in SASP.
FOXO4-DRI: If accessible (e.g., through clinical trials or future commercialization), FOXO4-DRI could be prioritized for its targeted senolytic action, but it’s not currently practical.
Dosing During Cessation: Administer fisetin or quercetin during rapamycin “off” periods (e.g., days 4-7 of a weekly cycle) to prevent SASP rebound. For example, take fisetin (500 mg) for 2-3 consecutive days during the cessation period, repeating weekly or biweekly, based on protocols from senolytic studies (e.g., Kirkland et al., 2017, Aging Cell).
Important Considerations
Consult a Healthcare Provider: These compounds, especially berberine and experimental therapies like FOXO4-DRI, can interact with medications or cause side effects (e.g., gastrointestinal issues for berberine, potential liver effects for flavonoids). Medical supervision is essential, particularly for rapamycin cessation protocols.
Source Quality: Use high-purity fisetin or quercetin from reputable suppliers with third-party testing to ensure efficacy and safety.
Monitoring: Track inflammatory biomarkers (e.g., C-reactive protein, IL-6, mentioned on Page 8) to assess SASP suppression during rapamycin cessation.
Research Gaps: The paper’s findings are based on in vitro fibroblast models, not human trials, and none of these adjuncts are directly tested for rapamycin cessation in the study. Human data on fisetin and quercetin are emerging but limited, and FOXO4-DRI remains experimental.
Conclusion
Fisetin is the best adjunct to prevent SASP during rapamycin cessation due to its senolytic and NF-κB inhibitory effects, directly addressing the p65-driven SASP rebound described in the PNAS article. Quercetin is a close second, with similar mechanisms but potentially lower bioavailability. Berberine is a supportive option for its anti-inflammatory and mTOR-inhibitory effects but is less effective alone. FOXO4-DRI is promising but currently inaccessible. A combination of fisetin (500 mg/day, 2-3 days/week during cessation) and berberine (500-1000 mg/day) could optimize SASP prevention while supporting longevity goals. Consult a healthcare provider to tailor this regimen and monitor outcomes. If you’d like, I can search X or the web for additional data on these compounds or specific protocols—let me know!
