Take high-dose vitamin C before exercise and you will reduce the exercise-induced oxidative stress that is, in part, the stimulus for mitochondrial biogenesis. Take high-dose NAC around a resistance training session and you may blunt the muscle protein synthesis response. Take antioxidants throughout the day without measuring your actual oxidative stress status, and you may be solving a problem you do not have while creating others you have not considered.
This is not an argument against antioxidants. Vitamin C, glutathione, NAC, CoQ10, alpha-lipoic acid — these are genuine clinical tools with real evidence bases in specific applications. The argument is more specific: antioxidants are context-dependent, timing-dependent, and dose-dependent in ways that the supplement industry is not commercially motivated to explain. The instruction on the bottle says "take one capsule daily." The clinical question is: when, why, at what dose, in what oxidative stress context, and for how long?
What Reactive Oxygen Species Actually Do
The immune system uses hydrogen peroxide and superoxide as weapons against pathogens — reactive oxygen species that kill bacteria and viruses. Macrophages produce a deliberate oxidative burst when destroying cellular debris. Exercise-induced ROS signals the nucleus to upregulate antioxidant enzymes (via Nrf2 pathway), stimulate mitochondrial biogenesis, and trigger muscle adaptation. Wound healing requires pro-oxidant signalling to initiate tissue repair. Cancer immunosurveillance uses ROS to identify and destroy abnormal cells.
Chronic, unresolved oxidative stress — where ROS production consistently exceeds the body's antioxidant capacity — damages DNA, lipids, and proteins progressively. This is the pattern in cardiovascular disease, neurodegeneration, metabolic syndrome, and accelerated ageing. The key distinction is between acute, purposeful ROS production (exercise, immune response, wound healing) and chronic, uncontrolled excess (poor diet, environmental toxins, chronic inflammation, mitochondrial dysfunction). These require completely different responses.
The supplement industry treats all reactive oxygen species as damage to be quenched. The clinical reality is that the body produces ROS intentionally, in specific contexts, for specific purposes — and has its own sophisticated antioxidant enzyme systems (superoxide dismutase, catalase, glutathione peroxidase) to resolve the oxidative load when the job is done. Supplementing exogenous antioxidants on top of a well-functioning endogenous system does not necessarily help it — it may simply add redundant scavenging activity or, in the case of high-dose supplementation around exercise, actively interfere with the adaptive signalling the exercise was designed to produce.
"The question is not whether you need antioxidant support. It is whether you have excess oxidative stress, what is driving it, and whether the antioxidant you are taking addresses the specific ROS species involved — at the right time and dose to support, rather than suppress, your body's own response."
The Exercise Timing Problem
This is the most practically significant antioxidant timing issue for active people and it is almost universally ignored in supplement marketing.
Resistance exercise and aerobic exercise both generate ROS — this is not a side effect, it is part of the mechanism. The ROS produced during a training session activates the Nrf2 transcription pathway, upregulating the body's endogenous antioxidant enzymes. It signals PGC-1α, initiating mitochondrial biogenesis — the process by which exercise creates new mitochondria and improves aerobic capacity. It triggers AMPK, the cellular energy sensor that drives metabolic adaptation. These are the adaptations you are training for. They are initiated, in part, by the oxidative stress of the training session itself.
Multiple studies have demonstrated that high-dose antioxidant supplementation — particularly vitamin C at doses above 1,000mg and vitamin E — taken around training blunts these signalling pathways. The exercise still happens. The adaptation is attenuated. You work as hard, feel the same burn, and get measurably less of the benefit.
This does not mean never take antioxidants if you train. It means timing matters. Antioxidants taken well away from training — in the evening, or on rest days — support overall antioxidant status without interfering with the acute exercise response. Antioxidants taken immediately before or after training compete with the signalling you just produced. The bottle does not tell you this. The clinical literature does.
The Hydrogen Water Question
Molecular hydrogen (H₂) has attracted significant research interest, primarily from Japanese groups, for a specific and clinically interesting reason: it is a selective antioxidant. Unlike broad-spectrum antioxidants that scavenge multiple ROS species indiscriminately, H₂ selectively targets hydroxyl radicals — the most reactive and most damaging ROS species — while leaving hydrogen peroxide and superoxide largely intact. This selectivity matters because H₂O₂ and superoxide are the signalling ROS that the body uses for adaptive processes. Hydroxyl radicals are the damaging species with no known beneficial role.
The evidence base for hydrogen, while still developing, includes cardiovascular, neurological, and metabolic applications. The concept is genuinely interesting and clinically distinct from blanket antioxidant supplementation.
The problem is how the market has delivered it. Hydrogen water machines producing continuous high-concentration H₂ water are expensive — £500 to £3,000 or more — and deliver H₂ in an uncontrolled, continuous fashion. Molecular hydrogen degrades rapidly on exposure to air, meaning concentration varies with how long the water has been sitting. You are drinking an unknown dose at an unknown interval without any relationship to clinical need. The social media version of hydrogen water positions it as something you should be drinking all day. This is the same one-size-fits-all logic applied to a compound that, by virtue of its mechanism, should be targeted to specific contexts rather than consumed continuously.
Quicksilver Scientific’s H₂ Elite tablets represent the more clinically defensible application of molecular hydrogen. Each tablet produces a measured dose of H₂ when dissolved in water — giving you control over dose, timing, and application context that a continuous-flow machine cannot provide.
The clinical applications where timed H₂ delivery makes specific sense: pre-exercise for mitochondrial support and selective ROS scavenging without blunting the adaptive signal; during periods of acute oxidative stress (illness recovery, post-surgical, intense training blocks); for clients with confirmed elevated oxidative stress markers on OAT (organic acid testing). In these contexts, the selectivity of H₂ makes it preferable to broad antioxidants.
The application where it makes less sense: drinking hydrogen water continuously throughout the day as a general wellness intervention. This turns a selective, timing-dependent clinical tool into a background supplement — and loses most of what makes it interesting in the first place.
Glutathione — The Delivery Problem
Glutathione is the body's master antioxidant — the most abundant intracellular antioxidant, produced in every cell, essential for detoxification, immune function, and redox regulation. When someone has chronic oxidative stress, heavy metal burden, or mitochondrial dysfunction, glutathione status is frequently depleted and clinically relevant to replete.
The problem is that standard oral glutathione supplementation is largely destroyed in the gut before reaching systemic circulation. The molecule is too large and too reactive to survive intact through gastric acid and intestinal enzymes at clinically meaningful doses. This is why a significant portion of the glutathione supplements sold in capsule and powder form produce minimal measurable change in cellular glutathione levels.
The clinically effective options are significantly more expensive:
- Liposomal glutathione — encapsulated in phospholipid vesicles that protect it through the gut and facilitate cellular uptake. Quicksilver Scientific's liposomal glutathione is the clinical benchmark for this delivery method. The absorption data is substantially better than standard oral.
- N-Acetyl Cysteine (NAC) — not glutathione itself but the rate-limiting precursor. The body uses NAC to synthesise cysteine and then glutathione. NAC is well-absorbed orally and has its own substantial evidence base for glutathione support, respiratory health, and detoxification. Often more cost-effective than liposomal glutathione for baseline support.
- Immunocal/Immunotec — undenatured whey protein providing cysteine in its most bioavailable form (as cystine, which crosses the blood-brain barrier as cysteine). The evidence base for Immunocal in raising intracellular glutathione is more substantial than for most oral glutathione supplements. Expensive and requires cold storage.
- IV glutathione — administered by clinicians in appropriate settings. Bypasses the absorption problem entirely. Clinical use in specific oxidative stress presentations — heavy metal detoxification, post-surgical recovery, chronic fatigue with confirmed depletion.
How to Know Whether You Need Antioxidant Support
The Organic Acids Test (OAT) measures several markers directly relevant to oxidative stress status: 8-hydroxy-2-deoxyguanosine (8-OHdG) — a marker of oxidative DNA damage; markers of mitochondrial dysfunction that indicate oxidative stress at the cellular energy production level; and several organic acids that reflect glutathione utilisation and detoxification load.
This is the clinical test that answers the antioxidant question properly. Not "how many antioxidants should I take" — that is a marketing question. "What is my actual oxidative stress load, what is driving it, and which antioxidant pathway is most relevant to address it?" That is a clinical question. It has a measurable, individual answer. And it produces a targeted intervention rather than a scatter of supplements hoping one of them addresses the actual problem.
High oxidative stress on OAT in a client who is training hard but not recovering — different intervention to high oxidative stress in a client with heavy metal burden and poor detoxification. Different again from the client whose OAT shows normal oxidative stress markers but who has been taking high-dose antioxidants for two years based on a podcast recommendation. In the last case, the most clinically appropriate action may be to stop supplementing and let the body's own antioxidant enzyme systems upregulate — which they will, in a healthy mitochondria, given the stimulus of the exercise-induced oxidative load they are no longer having quenched before it can signal.
Know your oxidative stress status before supplementing.
The Organic Acids Test measures your actual oxidative stress markers, mitochondrial function, and glutathione utilisation. The TDG programme includes OAT as one of its five tests — providing the individual data that makes antioxidant supplementation a clinical decision rather than a guess.
TDG Five-Test Programme → Blood Chemistry Health Audit — £295