Guide to antioxidants and redox balance

01  Oxidation: a normal part of being alive

Oxidation: a normal part of being alive

Aerobic life depends on oxygen and, precisely for that reason, has to manage oxidation.

In chemistry, to oxidise means that a molecule loses electrons. Another one receives them and is reduced: the two reactions form a pair, hence the term redox, short for reduction-oxidation. Inside the body, thousands of electron exchanges happen every second. The mitochondrial respiratory chain uses them to turn the energy in nutrients into ATP, the unit that drives muscle contraction, cellular transport, synthesis and repair.

During that flow, a small proportion of the oxygen can become reactive species. Specialised enzymes outside the mitochondria also produce them. This is not an unavoidable fault in an imperfect «machine»: in many contexts it is a deliberate function. Immune cells, for example, generate oxidants in specific compartments as part of their response; other cells use them to modify proteins temporarily and pass on information.

The word oxidation also describes everyday changes outside the body: a cut apple turning brown, or an oil going rancid. The analogy helps to picture the transfer of electrons, but it has limits. A living cell is not a passive object left out in the air. It detects changes, activates enzymes, recycles molecules, replaces components and adjusts production to demand.

That is why the useful question is not «how do I get rid of oxidation?», but «how does the body keep a level of signalling compatible with a good capacity to repair?» Modern redox biology distinguishes between physiological oxidant activity —sometimes called oxidative eustress— and an excessive or badly located load capable of favouring damage —oxidative distress— ^1,2.

A dynamic system, not a reservoir

Redox state changes with a meal, a training session, the time of day, sun exposure or an infection. Afterwards it has to return towards its usual range. In this field, «balance» does not mean stillness or a perfect ratio between oxidants and antioxidants: it means being able to produce the right signal, contain it in the right place and recover afterwards.

02  Free radicals, reactive species and cell signalling

Free radicals, reactive species and cell signalling

Not every reactive species is a radical, they do not all behave alike, and their effect depends on where, how much and for how long they appear.

A free radical is a chemical species with one or more unpaired electrons. That configuration can make it highly reactive, but on its own it does not predict what it will do inside a cell. The superoxide radical, the hydroxyl radical and nitric oxide differ enormously in half-life, mobility and targets.

The term reactive oxygen species (ROS) is broader. It includes radicals, such as superoxide, and non-radical molecules, such as hydrogen peroxide. The latter can move in a controlled way and reversibly oxidise specific amino acids in a protein. That change acts as a molecular switch: it modifies a pathway and can then be undone when the reducing system returns the protein to its previous state ³.

Four names worth telling apart

Dose is not the only criterion

In redox, concentration matters, but so does the compartment. A brief pulse of hydrogen peroxide next to a signalling protein is not the same as sustained exposure near a membrane. The cell organises sources and defences across mitochondria, cytosol, peroxisomes, nucleus and extracellular space; talking about «free radicals in the body» as if they were a single substance erases that architecture ^2,4.

This precision explains why laboratory comparisons of the «X has a hundred times more antioxidant power than Y» kind rarely rank ingredients well in people. A chemical assay in a tube measures how a substance reacts with a particular radical under chosen conditions. It says nothing about how much is absorbed, in what form it circulates, which tissue it reaches, how long it stays there or whether it activates the body's own defences.

Term	What it describes	Why it matters
Superoxide	Radical produced in mitochondria and by NADPH oxidase enzymes	Usually transformed quickly by superoxide dismutase
Hydrogen peroxide	Non-radical reactive species	Can take part in signalling or, if it builds up, feed more aggressive reactions
Hydroxyl radical	Highly reactive radical with local reach	Reacts close to where it forms; there is no enzyme that selectively «captures» it afterwards
Nitric oxide	Both a radical and a signalling molecule	Takes part in vascular regulation; its context and its interaction with other species change the outcome

03  From redox balance to oxidative stress

From redox balance to oxidative stress

Oxidative stress appears when oxidant signals stop being properly contained and unwanted changes to cellular molecules increase.

The term was proposed to describe an imbalance in favour of oxidants. Today it is used more precisely: it can refer to a disturbance of redox signalling or to molecular damage. The difference matters because a reversible signal is part of regulation; an accumulated change to lipids, proteins or DNA calls for repair, turnover or removal ⁵.

What can be modified

• Lipids. The polyunsaturated fatty acids in membranes can enter peroxidation chains. Their products include F2-isoprostanes and reactive aldehydes.
• Proteins. Some changes to cysteines are reversible switches; others generate carbonyls, cross-links or loss of function.
• DNA. Bases can be oxidised. 8-hydroxy-2’-deoxyguanosine —8-OHdG— is one of the most studied products, although its measurement and meaning depend on the method.

A compound reducing one of these markers in a trial does not automatically mean it «rejuvenates the cell» or produces an immediate sensation. It means that, under that protocol, a specific measure of balance or damage moved. That precision makes it possible to report positive results without turning a biomarker into a different promise.

Inflammation and oxidation talk to each other

The inflammatory response can increase the production of reactive species, and certain oxidative modifications can trigger new inflammatory signals. They are connected systems, not synonyms. A C-reactive protein level reports systemic inflammation; it does not directly measure redox state. Equally, a total antioxidant capacity in plasma does not summarise the whole immune response.

Accumulation and recovery

A brief exposure can resolve without leaving any relevant trace. Things change when high production, insufficient defences, reduced repair or a lack of time to recover coincide. Age, nutrition, training, sleep, tobacco, ultraviolet radiation, pollution, illness and certain treatments alter different parts of the system. There is no single profile and no universal cause.

04  The antioxidant network the body makes

The antioxidant network the body makes

Antioxidant defences work in a chain: they transform reactive species, recycle molecules and repair whatever could not be prevented.

The image of an antioxidant that «sacrifices itself» to neutralise a radical describes only part of the system. The body has very fast enzymes, small molecules that switch between oxidised and reduced states, minerals that let those enzymes work, and repair systems that remove damaged components.

First line: transform

Superoxide dismutase (SOD) converts superoxide into hydrogen peroxide. There are different forms depending on the compartment: one uses manganese in the mitochondria; others use copper and zinc. The product does not simply sit there in the cell. Catalase, especially abundant in peroxisomes, and the glutathione peroxidases reduce hydrogen peroxide to water. Several glutathione peroxidases need selenium.

Second line: reduce and recycle

Glutathione is a tripeptide made of glutamate, cysteine and glycine. Its reduced form, GSH, donates electrons in enzyme-catalysed reactions and becomes an oxidised form, GSSG. Glutathione reductase uses NADPH to return it to the reduced state. It is not a shield that is used up all at once: it is a cycle.

The thioredoxin system performs parallel roles in specific proteins and compartments. Vitamin C, vitamin E, coenzyme Q10, uric acid, bilirubin and many dietary compounds act in different aqueous or lipid environments. Some act directly; others modulate enzyme expression through transcription factors such as Nrf2.

Third line: repair and renew

A perfect defence does not exist, nor would it be necessary. Cells repair DNA, degrade altered proteins and renew membrane lipids. Autophagy and mitophagy remove components no longer worth keeping. Real antioxidant capacity therefore includes prevention, containment, recycling and repair.

The special role of cysteine

To synthesise glutathione, the cell needs all three of its amino acids. In many contexts, the availability of cysteine is the most limited step. N-acetyl-L-cysteine —NAC— is deacetylated and provides cysteine, which explains its place in the study of the glutathione system. That does not make it equivalent to taking glutathione, nor does it allow their milligrams to be added together: they are different molecules and follow different steps ⁶.

A network that adapts

A moderate oxidant signal can activate Nrf2 and increase the expression of defensive enzymes. This is one of the reasons why exercise and plant compounds are not understood solely as radical «scavengers». Sometimes their most interesting contribution is to provoke a proportionate adaptive response.

Layer	Examples	Function, simplified
Enzymes	SOD, catalase, glutathione peroxidase	Transform reactive species quickly
Reducing systems	Glutathione, thioredoxin, NADPH	Donate electrons and are recycled
Lipid antioxidants	Vitamin E, coenzyme Q10, carotenoids	Work in membranes and lipoproteins
Cofactors	Selenium, zinc, copper, manganese	Allow specific enzymes to work
Repair and turnover	Repair enzymes, proteasome, autophagy	Correct or remove altered components

05  Food: variety, matrix and colour

Food: variety, matrix and colour

A varied plant-based diet provides substrates, cofactors and signals that work together within a complex matrix.

The soundest dietary strategy is not to chase the food with the highest antioxidant score. It is to repeat a diverse base: vegetables and fruit, pulses, nuts, seeds, wholegrains, extra virgin olive oil, herbs and spices; plus adequate protein sources and fish where they form part of the pattern.

The World Health Organization keeps as a reference, for people over ten, at least 400 grams of fruit and vegetables a day and 25 grams of fibre from food ⁷. The figure does not turn five portions into an exact antioxidant recipe; it offers a simple anchor for increasing variety, potassium, folate, vitamin C, carotenoids, polyphenols and fibre.

In one intervention within the PREDIMED study, two variants of the Mediterranean diet reduced different markers of lipid and DNA oxidation compared with a control diet ³¹. The point is not to attribute the result to a single food, but to the pattern as a whole.

Eat the colour, without turning it into a rigid code

• Dark green: spinach, chard, kale and broccoli provide lutein, folates and other phytochemicals.
• Red and orange: tomato, watermelon, pepper, carrot, pumpkin and citrus provide different carotenoid families.
• Purple and blue: berries, red grapes and red cabbage concentrate anthocyanins and other polyphenols.
• White and beige: onion, garlic, cauliflower, mushrooms, pulses and nuts add sulphur compounds, minerals and fibre.

Colour is an invitation to vary, not a perfect taxonomy. Lycopene is red, lutein is yellow and many polyphenols cannot be seen. Rotation across the week matters more than completing every colour on a single plate.

The matrix changes absorption

Carotenoids are fat-soluble. A small amount of fat —olive oil or nuts, for instance— helps them join intestinal micelles. Cooking and blending tomato breaks down structures and can increase the availability of lycopene; that does not make raw tomato worthless. Vitamin C, by contrast, is sensitive to heat and long storage. Combining raw and cooked broadens the profile.

Food also provides things that do not fit in a capsule: volume, satiety, water, fermentable fibre and thousands of molecules in dietary proportions. That is why a supplement plays a role of precision and concentration, not of replacement.

Four everyday decisions with high returns

1. Add a vegetable to lunch and dinner, not just a token side.
2. Alternate sources: leaves, brassicas, tomato, berries, citrus and pulses.
3. Use extra virgin olive oil as the main cooking fat within a balanced diet.
4. Keep plain or roasted nuts without excess salt as a regular option.

06  Exercise, adaptation and recovery

Exercise, adaptation and recovery

Exercise creates a transient redox disturbance and, when the dose is right, teaches the body to respond better.

During muscle contraction the flow of electrons increases and different sources of reactive species are activated. That pulse takes part in pathways that stimulate mitochondrial biogenesis, glucose uptake and the expression of antioxidant enzymes. With repeated training, the muscle does not simply end up «less oxidised»: it becomes more competent at handling the demand ⁸.

This logic is called hormesis: a moderate exposure activates an adaptation that improves the later response. It does not mean that any effort is good in any amount. An exhausting session with little rest, an abrupt progression, or intense training combined with an energy deficit can raise the load beyond the recovery available.

The three variables that matter most

• Progression. The stimulus should grow more slowly than the capacity to absorb it.
• Alternation. Spacing out days and muscle groups allows repair and supercompensation.
• Fuel. Energy, protein, carbohydrate, fluids and micronutrients sustain recovery; a supplement works on top of that base, not instead of it.

Antioxidants around training

Research with megadoses of vitamins C and E offers a lesson in precision. In an eleven-week trial, 1,000 mg of vitamin C and 235 mg of vitamin E a day blunted some cellular markers of adaptation to endurance training, although they did not erase the improvement in performance ⁹. The result belongs to those vitamins, amounts and protocol; it does not license the claim that all antioxidants interfere or that they should be avoided.

The practical conclusion is more elegant: there is no need to try to eliminate every oxidant signal from exercise. A diet rich in plant foods fits well with training; when a supplement is used, it is worth avoiding the «more is better» logic, especially with isolated megadoses.

How to watch recovery

Sleep, appetite, motivation, muscle soreness, performance and resting heart rate give more useful context than chasing an oxidative figure. If the same load keeps getting harder, the first thing to adjust is usually volume, intensity, food and rest.

07  Sun, tobacco, pollution, alcohol and sleep

Sun, tobacco, pollution, alcohol and sleep

Cellular protection is built as much by reducing avoidable exposures as by strengthening the capacity to recover.

Ultraviolet radiation: physical protection first

UV radiation can cause direct DNA damage and generate reactive species in the skin. No food or supplement replaces shade, clothing, proper sunglasses and well-applied sunscreen. Checking the UV index and avoiding deliberate intense exposure are first-order measures ¹⁰.

Ingested carotenoids are studied as part of the skin's nutritional environment, but they do not work as an oral sunscreen and do not license longer exposure. The right combination is complementary: external sun protection plus internal nutrition, each in its own role.

Tobacco: a concentrated source of oxidants

Tobacco smoke contains radicals and substances that favour oxidative and inflammatory responses. Here the highest-impact decision is not to add antioxidants: it is not to smoke and to avoid second-hand smoke. Replacing that priority with a supplement would invert the order of magnitude ^11,33.

Pollution: reducing the load you can

Airborne particles and polluting gases can trigger the production of reactive species in the airways and the vascular system ³². You cannot always choose the air, but you can check local warnings, keep intense exercise away from busy roads at peak times, ventilate when outdoor quality is better, and follow the protocols recommended during high-pollution episodes.

Alcohol: metabolism and context

Alcohol metabolism alters the liver's redox state and, with high or repeated intakes, increases the oxidative load. The polyphenols in a drink do not offset the ethanol. If you do drink, less is better for health; an antioxidant guide does not turn wine into a necessary source of resveratrol.

Sleep and rhythms: time to repair

Sleep is not an antioxidant, but it organises metabolism, immune function and repair. Acute deprivation and shift work alter oxidative markers in some studies, with variable responses. The robust recommendation does not depend on a biomarker: keep a reasonably stable schedule, daylight, darkness at night and enough time to sleep.

A simple hierarchy

Priority	Action
1	Do not smoke, and avoid second-hand smoke
2	Protect skin and eyes from excess UV radiation
3	Keep a varied diet, physical activity and regular sleep
4	Limit alcohol and reduce exposure to pollution where possible
5	Consider concentrated ingredients as a supplement, not as compensation

08  What can be measured and what cannot

What can be measured and what cannot

There is no single clinical test that translates the whole of redox balance into a personal score.

Studies use different markers depending on the molecule they want to observe. F2-isoprostanes report lipid peroxidation and, measured by mass spectrometry, are among the most robust indicators ¹². Malondialdehyde (MDA) and TBARS assays are common, but less specific and very sensitive to procedure. 8-OHdG relates to nucleic acid oxidation; protein carbonyls, to protein modifications.

Other measurements describe the defences: reduced and oxidised glutathione, SOD or glutathione peroxidase activity, or total antioxidant capacity (TAC). TAC reflects how a sample reacts in an assay; it is not the same as «total cellular protection» and does not allow two people to be compared directly.

Why results vary

Recent food, exercise, time of day, tobacco, infection, medication, sample handling and analytical method can all change the figure. An isolated marker does not diagnose «chronic oxidative stress», and commercial «oxidative age» panels are not part of standardised routine testing ³⁰.

In practice, a full blood count, ferritin, glucose, lipid profile, liver function or TSH can be more useful when there is tiredness or another symptom, because they answer specific clinical questions. Ordering and interpreting them is a matter for a healthcare professional.

09  Timeframes used in the studies

Timeframes used in the studies

The length of a trial tells you when a result was measured, not when an antioxidant «should be felt».

Window	What has been studied	How to read it
Hours or days	Absorption of CoQ10 or carotenoids; changes after exercise or a meal	Pharmacokinetics and acute response, not accumulated protection
3–8 weeks	Oxidative markers with NAC, CoQ10, curcuminoids or astaxanthin	Results for the ingredient, dose and population in the protocol
8–16 weeks	Macular pigment, skin and other outcomes with carotenoids	Concentration in tissues requires consistency
6 months	Oral glutathione stores in a trial in healthy adults	The effect was gradual and dependent on dose and time

10  Human evidence by ingredient

Human evidence by ingredient

Each ingredient occupies a different position within the system; evidence always belongs to the form, the amount and the outcome studied.

Reading the whole without mixing evidence

A clear physiological role. NAC is an acetylated form of cysteine. After metabolism it can contribute to the availability of this amino acid, which is needed to synthesise glutathione. It also has a thiol group able to take part in specific chemical reactions. Its medical use as a mucolytic and as an antidote follows its own protocols, which should not be confused with nutritional use.

In a small trial with 28 physically active men, 1,200 mg a day for eight days increased glutathione and altered several markers after exercise ¹³. The finding belongs to that population, that context and that amount; it does not allow the same result to be expected with a different dose or within a combination.

A central endogenous system. Reduced glutathione —GSH— is the form available to donate electrons in enzymatic reactions. For years it was assumed that digestion would prevent stores being changed by the oral route; the trials show a more nuanced picture.

In a randomised, double-blind study, 54 non-smoking adults took 250 or 1,000 mg a day for six months. Glutathione concentrations rose in several compartments, in a pattern dependent on time and dose; after a month of washout they returned towards baseline ¹⁴. Another trial, with 1,000 mg but lasting only four weeks, saw no changes: the measurement window matters as much as the dose¹⁵. Duration, formulation, population and method all help to explain why not every study is equivalent.

Established mitochondrial function. Coenzyme Q10 alternates between ubiquinone and ubiquinol. In the inner mitochondrial membrane it carries electrons between complexes of the respiratory chain; in its reduced form it also takes part in protecting lipid environments.

A meta-analysis of 34 randomised trials and 2,012 participants found an increase in total antioxidant capacity and a reduction in MDA, with favourable results in the 100–150 mg a day subgroup ¹⁶. Populations and durations were heterogeneous. The result describes biomarkers measured in those protocols, not a response attributable to any product containing CoQ10.

High standardisation. Curcuminoids are polyphenols from the rhizome of Curcuma longa. They are studied for their interaction with redox and inflammatory pathways, including Nrf2-related signalling. A meta-analysis of randomised trials found improvements in some antioxidant markers, with substantial heterogeneity across doses, preparations and populations ¹⁷.

Free curcumin is poorly absorbed and rapidly metabolised. That is why milligrams of a conventional extract should not be compared with phytosomal, micellar or piperine-combined preparations. On a label, the amount can only be read correctly alongside the type of extract, its standardisation and its formulation technology.

Characterised polyphenols. Pomegranate contains ellagitannins that release ellagic acid during digestion. Some gut bacteria then transform it into urolithins, but not everyone produces the same ones or in the same amount. Different metabotypes have been described, which helps to explain the variability between participants ¹⁸.

Trials with juice, extracts, ellagic acid or urolithin A given directly are not equivalent. A synthesis of pomegranate trials found favourable signals in glutathione peroxidase, TAC and some peroxidation markers, with low-certainty evidence and inconsistent results ¹⁹. Results should always be attributed to the material given: studies of preformed urolithin A do not transfer to a pomegranate extract.

The tomato carotenoid. Lycopene is a red carotenoid with no provitamin A activity ³⁶. It is found mainly in tomato and its products, watermelon and pink grapefruit. Heat processing and the presence of fat can help its availability; a small study found a greater rise in plasma lycopene when tomato was cooked with olive oil ²⁰.

A review of human interventions with tomato or lycopene found favourable results for UV-induced erythema and some skin parameters, across a range of preparations and doses ²¹. Those results belong to specific preparations and amounts and do not turn lycopene into an oral sunscreen.

A dietary pigment. Lutein is a xanthophyll the body does not synthesise ³⁵. Together with zeaxanthin and meso-zeaxanthin it concentrates selectively in the macula, where it filters part of short-wavelength visible light and takes part in the retinal antioxidant environment.

A trial in 115 healthy adults used 10 mg of lutein plus 2 mg of zeaxanthin for a year and recorded an increase in macular pigment density and changes in specific visual measures ²². The result corresponds to that combination; it does not extrapolate to other amounts or to lutein without zeaxanthin.

A polar fat-soluble carotenoid. Astaxanthin is a red xanthophyll that the microalga Haematococcus pluvialis accumulates under stress. Its structure lets it sit across lipid membranes and has prompted studies on peroxidation, skin, exercise and visual function.

In an eight-week trial with 42 women, 2 or 8 mg a day increased plasma astaxanthin and altered a marker of DNA oxidation, while other markers did not change ²³. Another trial, with 6 or 12 mg over twelve weeks, reduced phospholipid hydroperoxides in red blood cells ²⁴. As with every ingredient in this guide, the results belong to the arms studied; the 4 mg dose sits within the safety range assessed by EFSA for adults.

11  Forms, standardisation and bioavailability

Forms, standardisation and bioavailability

An ingredient's surname can matter as much as its name.

“Reduced” does not mean “fewer milligrams”

In glutathione, “reduced” describes its redox state, not a lowered dose. GSH is the form able to donate electrons; GSSG is the oxidised form.

A standardised extract gives two figures

“100 mg of turmeric” tells you the weight of the extract. “95% curcuminoids” lets you calculate 95 mg of the standardised group. The same applies to pomegranate: 100 mg at 40% provides 40 mg of ellagic acid. This calculation does not prove absorption or effect, but it does allow labels to be compared transparently.

Food matters

CoQ10, lycopene, lutein and astaxanthin are fat-soluble. Taking them with a meal containing some fat supports the normal mechanics of absorption. That does not call for a heavy meal: olive oil, avocado, egg, yoghurt or nuts can do the job, depending on the diet. This is why formulas combining these actives usually say to take them with a meal containing some fat: it is not an arbitrary requirement, but the condition that allows fat-soluble compounds to join the intestinal micelles.

12  How to read a multi-component formula

How to read a multi-component formula

A multi-component formula gains clarity when every active is identified, quantified and properly characterised.

1. Formulation layers

A multi-component formula can bring together water-soluble and fat-soluble molecules, precursors, coenzymes, extracts and carotenoids. This structure makes it easier to check what each dose provides and to spot possible redundancies.

2. Verifiable identity

NAC should be named as N-acetyl-L-cysteine; glutathione, with its form; CoQ10, with its presentation; botanicals, with species, part used and standardisation; astaxanthin and lutein, with their source.

3. Transparent doses

A proprietary blend usually hides how much each component provides. Declaring them individually, by contrast, allows amounts to be compared and a studied clinical dose to be told apart from a complementary dose within a formula. A formula that declares each active individually —with no proprietary blends— lets you apply this criterion straight from the label.

4. Rationale versus synergy

Two ingredients can fit into neighbouring steps without any trial showing that together they produce a greater effect. In that case we speak of a rationale of complementarity, not of demonstrated clinical synergy.

5. Safety of the whole

Interactions add up even when milligrams do not. A good formula includes clear warnings, avoids stacking products with the same active and places the dose within a meal when absorption calls for it.

13  A map for finding your way among the popular options

A map for finding your way among the popular options

The best choice depends on the question: nutritional cover, a specific ingredient or a multi-pathway formula.

There is no universal hierarchy. A nutrient deficiency is corrected differently from an interest in carotenoids or the choice of a general formula. Official reviews of antioxidant supplements also point out that results from foods and from capsules are not interchangeable ³⁴. The value is not in collecting bottles, but in choosing a strategy you can understand and avoiding duplication.

Option	What it provides	What to check
A varied diet	The complete matrix, fibre and a diversity of phytochemicals	Consistency and variety across the week
Vitamin C or E	Essential nutrients with defined functions	Dietary intake, dose and avoiding unnecessary megadoses
Zinc or selenium	Cofactors of antioxidant defences	Not exceeding requirements or combining multiple sources
NAC or glutathione alone	A specific focus on the glutathione pathway	Form, amount, tolerance and goal. Check whether a multi-component formula already includes them before adding another product.
CoQ10 alone	A mitochondrial and lipid focus	Formulation, food and interactions. Check whether a multi-component formula already includes them before adding another product.
A single carotenoid	A specific question about tissue or intake	Source, dose and evidence for the outcome
A multi-component formula	Several actives in a single routine	Transparency, standardisation and rationale. If the goal involves several pathways at once, a formula with individually declared actives avoids duplication and simplifies the routine.

14  Safety, precautions and interactions

Safety, precautions and interactions

A well-designed formula also explains clearly when to seek advice and which combinations to avoid.

Tolerance depends on the ingredient, the amount, the person and the combinations. In studies and everyday use, what has mainly been described are digestive complaints such as nausea, reflux, diarrhoea or abdominal discomfort. Taking the formula with food usually helps and, in addition, supports the absorption of CoQ10 and carotenoids.

It is advisable to consult a healthcare professional before starting if you take long-term medication, have a diagnosed condition or have surgery scheduled. ANTIOX PRO is not indicated during pregnancy or breastfeeding, nor for infants, children or adolescents. It should not be combined on the same day with other supplements providing astaxanthin esters.

ANTIOX PRO is not recommended for prolonged periods or alongside medicines without first consulting a doctor or pharmacist.

Interactions and relevant situations

• NAC: may enhance the vasodilatory effects of nitroglycerin and contribute to headache or low blood pressure; an interaction with carbamazepine has also been described ²⁵.
• CoQ10: warrants review with warfarin, insulin and certain oncology treatments ²⁶.
• Turmeric and curcuminoids: not recommended with liver or biliary abnormalities or gallstones in the bile duct. Rare cases of liver injury have been reported, especially with high-bioavailability preparations ²⁷²⁸.
• Pomegranate and concentrated extracts: clinical information on interactions is limited; with long-term or narrow-margin medication it is worth checking first.
• Astaxanthin: the European regulator considered a supplementary intake of 8 mg/day safe for adults; ANTIOX PRO provides 4 mg ²⁹.

15  Frequently asked questions

Frequently asked questions about antioxidants and redox balance

Eleven short answers to separate concepts, expectations and practical decisions.

What is an antioxidant?

Are free radicals always harmful?

What is oxidative stress?

Which foods provide the most antioxidant variety?

Does a good diet make any supplement unnecessary?

What is the difference between NAC and glutathione?

Why do turmeric and pomegranate extracts show percentages?

Do antioxidants protect against the sun?

Can several antioxidant supplements be combined?

What timeframes do the studies use?

Is a very high dose better?

16  How this guide was made

How this guide was made

The evidence has been organised by question, not by how popular an ingredient is.

Priority has been given to systematic reviews, meta-analyses, human trials and official sources. Cell or animal studies are used only to explain mechanisms and are identified as such. Each human result is accompanied, where relevant, by dose, duration, population and biomarker.

The guide distinguishes four levels: physiological function; the result for an ingredient; the rationale for a combination; and evidence for the complete formula. Results obtained with urolithin A given directly are not transferred to a pomegranate extract, nor are trials of 10 mg plus zeaxanthin transferred to 4 mg of lutein. The doses described are those used in the studies, not recommendations for use.

This content is informational and does not replace assessment by a healthcare professional.

17  Our approach

Our approach

PLENIAGE applies a transparent formulation standard: identity, standardisation and declared amounts for each of the eight actives.

ANTIOX PRO is organised in four layers:

We do not use an “antioxidant potency” ranking to order these pieces. The label declares each amount individually, the standardisation of the two plant extracts and the source of the carotenoids.

The complete combination does not have a clinical trial of its own. That is why it is presented through its architecture and formulation rationale, while the scientific results are attributed to the ingredient, amount and protocol studied. This transparency makes it possible to compare the formula with sound criteria.