High-dose antioxidant supplementation (especially high-dose Vitamin C + E) can blunt some exercise-induced mitochondrial biogenesis adaptations when taken immediately around strength training, as the ROS generated during training serve as a signaling molecule for training adaptation. The practical guidance: moderate doses at maintenance levels are fine for recovery support; reserve higher acute doses for illness or high-pollution environments. Most research showing blunted adaptations used very high doses (1,000 mg Vitamin C + 400 IU Vitamin E daily) that exceed typical maintenance use.*

Oral glutathione is largely degraded in the gastrointestinal tract before absorption -- the tripeptide (glutamate-cysteine-glycine) is broken down by intestinal enzymes. The body synthesizes glutathione intracellularly, and the rate-limiting step is cysteine availability. NAC provides the cysteine precursor in a form that survives digestion and enters cells, where intracellular glutathione synthesis then occurs. Liposomal glutathione formulations improve absorption somewhat, but NAC remains the gold-standard approach for raising intracellular GSH.*

Astaxanthin's unique structure -- polar groups at both ends connected by a polyene chain -- allows it to span the entire lipid bilayer and neutralize ROS on both the inner and outer membrane surfaces simultaneously. Beta-carotene and lycopene sit embedded in the hydrophobic core of the membrane and only protect one area. Astaxanthin's singlet oxygen quenching rate is 6,000x higher than Vitamin C, 10x higher than beta-carotene, and it does not become pro-oxidant at high concentrations like beta-carotene can.*

Fat-soluble antioxidants (Ubiquinol CoQ10, Astaxanthin, Vitamin E, Resveratrol) should be taken with a meal containing fat, as they require dietary fat for absorption via micellar packaging. Astaxanthin absorption increases significantly with fat. Vitamin C and NAC can be taken at any time, though Vitamin C with meals reduces the risk of GI sensitivity at higher doses. For athletes, avoid high-dose antioxidants immediately before or during training to preserve training signal.*

Yes -- antioxidant synergy is well-documented. Vitamin C regenerates Vitamin E. Alpha-Lipoic Acid regenerates both. NAC supports glutathione that regenerates Vitamin C. Quercetin enhances Vitamin C activity and spares it from rapid oxidation. These compounds work as a network, not in isolation -- a well-chosen multi-antioxidant stack is more effective than megadosing a single compound. Start with a few and add based on your specific oxidative stress profile and health goals.*

A high-quality diet rich in colorful vegetables, fruits, and whole foods provides substantial antioxidant support. For most people eating well and living with low environmental stress, the supplement benefit is incremental. The strongest cases for supplementation: Ubiquinol CoQ10 (not obtainable in meaningful amounts from diet), NAC (no direct food source), and Astaxanthin (present in salmon at low levels -- you'd need 200g salmon/day for therapeutic astaxanthin). Vitamin C and polyphenols can be substantially obtained from diet if that diet is genuinely high in vegetables and fruit.*