Longevity supplements in the Netherlands and Europe: processes, quality, and safety

Longevity supplements are substances being researched in relation to biological processes that can change during aging. These include cellular energy production, NAD⁺ metabolism, glutathione synthesis, and methylation. Well-known examples are NMN, GlyNAC, and TMG.

None of these supplements have been convincingly proven as a means to extend human lifespan. Research focuses primarily on biological mechanisms, safety, biomarkers, and short-term functional outcomes. A change in a blood value is not automatically the same as a noticeable health benefit.

Anyone comparing longevity supplements in the Netherlands and Europe should therefore not only look at promising mechanisms. The dosage used, transparent labeling, origin, independent laboratory testing, possible side effects, and the quality of human evidence are also important. In addition, a product must comply with European rules and any additional requirements of the country in which it is sold.

On this page, you can read how mitochondria, NAD⁺, glutathione, and methylation are linked, what research into NMN, GlyNAC, and TMG does and does not show, and how to assess quality and safety. For a practical selection aid, also view our guide on supplements for healthy aging.

What are longevity supplements?

Longevity supplements are dietary supplements offered or researched in relation to healthy aging and underlying cellular processes. “Longevity supplement” is not a separate, legally defined product category. The term itself therefore says nothing about proven efficacy, quality, or safety.

Longevity at the cellular level refers to research into cellular and molecular processes that change during aging. In this context, the word longevity is not just about lifespan, but also about how long cells, tissues, and organs can continue to perform their functions.

Cells do not all age in the same way, nor at the same rate. Age-related changes can differ per cell type, organ, person, and living environment. Genetic predisposition, nutrition, exercise, sleep, illness, medication, and exposure to harmful substances can all play a role.

Researchers use different models and biomarkers to study these changes. Examples include measurements of mitochondrial function, glucose metabolism, inflammatory markers, epigenetic changes, DNA damage, protein quality, and cellular senescence.

The scientific framework of the hallmarks of aging describes various interconnected characteristics of biological aging. This framework is intended to organize research and is not a diagnostic test with which the biological age of a single person can be easily determined.

The World Health Organization describes healthy aging as the development and maintenance of functional capabilities that enable well-being in later life. Thus, healthy aging is broader than just cellular biomarkers or supplement use.

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What changes during aging?

Aging is not a single process. At the biological level, various forms of molecular and cellular damage can arise over time. At the same time, maintenance, repair, and regulation systems can change.

Frequently discussed changes within cellular aging research include:

• changes in the function and quality of mitochondria;
• changes in the availability and processing of nutrients;
• accumulation of damaged or misfolded proteins;
• changes in DNA, chromatin, and epigenetic regulation;
• changes in cell signaling and communication between cells;
• increase in some inflammation-related processes;
• changes in the balance between oxidative and reductive reactions;
• decline in the function of certain stem cell populations;
• accumulation of senescent cells in some tissues;
• changes in the microbiome and the interaction between microorganisms and the body.

These changes do not occur to the same extent in everyone. Moreover, they do not proceed linearly. A higher chronological age therefore does not automatically mean that every biological function has diminished to the same degree.

A biomarker associated with age is also not automatically the cause of aging. Conversely, changing a single biomarker does not necessarily mean that general health, quality of life, or lifespan improves.

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Mitochondria and cellular energy

Mitochondria are cell components involved in the production of ATP. ATP, short for adenosine triphosphate, is an important energy carrier that cells use for processes such as muscle contraction, active transport, signal transmission, and the formation of new molecules.

In the production of ATP, nutrients are processed via various metabolic pathways. Some of these reactions take place in the mitochondria. This requires oxygen, enzymes, and cofactors.

In addition to ATP production, mitochondria also have other functions. They are involved in calcium balance, cell signaling, heat production, and processes that determine how a cell responds to damage or stress.

During aging, the quantity, quality, and function of mitochondria in certain cells and tissues can change. However, the extent to which this happens differs per organ, health situation, and person.

The feeling of fatigue is not the same as a measured problem with mitochondria. Fatigue can be related to sleep deprivation, stress, anemia, thyroid problems, infections, medication, cardiovascular disease, and psychological factors, among other things. Persistent fatigue should therefore not be interpreted exclusively as a problem of cellular energy.

For a practical comparison of energy, redox processes, methylation, and hydration, read further in our guide on cellular energy, recovery, and balance.

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The role of NAD⁺

NAD⁺ stands for nicotinamide adenine dinucleotide. It is a co-enzyme that can accept and donate electrons during redox reactions. Through these reactions, NAD⁺ is involved in the processing of carbohydrates, fats, and other nutrients.

NAD⁺ is also a substrate for various enzymes, including sirtuins, PARP enzymes, and CD38. These enzymes are involved in diverse processes such as cell signaling, DNA damage response, and calcium regulation.

It is often stated that NAD⁺ levels automatically decline with age. For some animal models and human tissues, indications of a decline have been found, but human data are still limited and not the same in every tissue.

A clinical review from 2025 concluded that convincing evidence for an age-related decline of NAD⁺ in humans comes from only a limited number of studies. The authors emphasize that differences between tissues, measurement methods, and research designs are important.

Read the review NAD⁺ precursor supplementation in human ageing: clinical evidence and challenges.

Furthermore, a 2026 study found that NAD⁺ levels in whole blood remained relatively stable with age across seven human cohorts. The researchers concluded that NAD⁺ in whole blood may therefore not be a reliable general biomarker for aging.

View the study Human whole-blood NAD⁺ levels do not vary with age or lifestyle interventions.

What does NMN have to do with NAD⁺?

NMN stands for nicotinamide mononucleotide and is an intermediate in pathways through which the body can form NAD⁺. Therefore, NMN is studied as an NAD⁺ precursor.

Small human studies show that oral NMN intake under certain research conditions can increase the measured NAD⁺ level in the blood. This does not prove that extra NMN automatically leads to more subjective energy, slower cellular aging, or a longer lifespan.

View, for example, the placebo-controlled NMN study in healthy older men.

Read more within Every Day Better about:

• what NMN is;
• NMN and NAD⁺ metabolism;
• NMN dosages from research;
• possible NMN side effects and points of attention;
• comparing NMN research and product information.

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Glutathione and oxidative balance

Glutathione is an endogenous molecule consisting of glutamate, cysteine, and glycine. It is involved in redox reactions and works together with various enzymes that help cells deal with reactive molecules.

Oxidative stress arises when the production of reactive oxygen species and the available regulation and protection mechanisms become unbalanced. However, reactive oxygen species are not exclusively harmful. They also have functions within cell signaling and defense.

The goal is therefore not to block all oxidative processes. Too strong a shift to a reductive state can also be undesirable. Within scientific research, one therefore speaks of redox balance instead of the complete removal of free radicals.

Why is GlyNAC being studied?

GlyNAC is a combination of glycine and N-acetylcysteine, abbreviated as NAC. Glycine and cysteine are involved in the formation of glutathione. Therefore, it is being investigated whether the availability of these substances can influence glutathione synthesis and related biomarkers.

In a placebo-controlled study, 24 older adults were divided into a GlyNAC group and a placebo group. The intervention lasted sixteen weeks. The researchers reported changes in various biomarkers and functional measurements.

Because each research group consisted of only twelve older participants, larger and independent studies are needed before broad conclusions can be drawn.

View the randomized GlyNAC study in older adults.

Read more within Every Day Better about:

• what GlyNAC is;
• the difference between GlyNAC and NAC;
• human research into GlyNAC;
• GlyNAC dosages from research;
• possible side effects and points of attention.

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Methylation and homocysteine

Methylation is a collective term for biochemical reactions in which a methyl group is transferred from one molecule to another. Methylation reactions are involved in diverse processes, including the formation of creatine, phospholipids, neurotransmitters, and various forms of cellular regulation.

Methylation is sometimes described too simply as a system that is “on” or “off.” In reality, there are many different methyltransferases, pathways, and tissue-specific processes. Taking in more methyl groups therefore does not automatically mean that methylation proceeds better.

Homocysteine is an intermediate within the methionine cycle. It can be converted to cysteine or re-methylated to methionine. Folate, vitamin B12, vitamin B6, methionine synthase, and betaine-homocysteine methyltransferase play a role in this, among others.

Read the scientific background on methylation reactions and homocysteine metabolism.

What role does TMG play?

TMG stands for trimethylglycine and is also called betaine. TMG can function as a methyl group donor. Via the enzyme betaine-homocysteine methyltransferase, betaine can contribute to the conversion of homocysteine to methionine.

This biochemical function does not prove that extra TMG is necessary for everyone. Also, a change in homocysteine does not automatically mean that general health, biological age, or lifespan improves.

TMG is used alongside NMN in some supplement routines, but there is no convincing evidence that every NMN user needs extra TMG or that TMG enhances the effect of NMN.

Read more within Every Day Better about:

• what TMG is;
• research into TMG;
• TMG dosage and use;
• possible side effects and points of attention;
• the difference between TMG and betaine.

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How are these processes connected?

Mitochondria, NAD⁺, glutathione, and methylation are not completely separate systems. Biological processes are connected via metabolic pathways, enzymes, nutrients, and cellular signals.

However, the connection does not mean that every process must be influenced simultaneously with a supplement. Also, a theoretical connection between two pathways does not prove that a combination of supplements has a synergistic health effect.

Examples of biological connection are:

• NAD⁺ is involved in redox reactions associated with the processing of nutrients.
• Mitochondria produce reactive molecules that also have a function within cell signaling.
• Glutathione and glutathione-dependent enzymes are involved in the redox regulation of cells.
• The methionine cycle and transsulfuration pathway connect methyl group metabolism with the formation of cysteine.
• Nutritional status, exercise, illness, and medication can influence multiple pathways at once.

A systems-oriented explanation can help to understand connections, but should not be translated into the assumption that an extensive supplement stack is automatically better than one targeted product or no supplement at all.

For the practical differences between the four pillars, you can consult our page on NAD⁺, glutathione, methylation, and hydration.

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Can supplements support longevity?

Supplements can provide specific nutrients or other substances, but there is no supplement that has been convincingly shown to extend human lifespan. The word longevity should therefore not be interpreted as a proven life-extending effect.

NMN, GlyNAC, and TMG are studied from different biological perspectives:

• NMN is studied as an intermediate within the formation of NAD⁺.
• GlyNAC provides glycine and NAC, substances involved in glutathione synthesis.
• TMG can function as a methyl group donor and is involved in homocysteine metabolism.

Most human studies on these substances focus on biomarkers, tolerability, or short-term functional outcomes. That is different from demonstrating that a substance improves healthy aging as a whole.

The significance of a research result depends, among other things, on:

• the number of participants;
• the age and health of the participants;
• the substance form and dosage used;
• the duration of the study;
• the chosen control group;
• the measured outcome;
• whether the result has been independently replicated;
• possible conflicts of interest and funding sources.

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Comparing NMN, GlyNAC, and TMG

NMN, GlyNAC, and TMG are often placed under the same longevity umbrella, but they are not interchangeable. They provide different substances and are researched from different biological pathways.

Which option is appropriate depends on the goal, health situation, diet, medication, and the quality of the evidence. It is not scientifically substantiated to advise these three substances as a standard complete “longevity stack” to everyone.

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What do we not yet know?

Research into the biology of aging is developing rapidly, but many fundamental and clinical questions have not yet been answered.

Human long-term studies are limited

Many studies on NMN, GlyNAC, and TMG last a few weeks or months. As a result, little is often known about long-term efficacy, safety, and the significance of small changes in biomarkers.

Animal research is not the same as research in humans

Mice, worms, fruit flies, and cell cultures are valuable for studying mechanisms. However, results from these models cannot be directly translated to health effects or life extension in humans.

Blood values do not automatically represent all tissues

A substance may be measured or regulated differently in blood than in muscles, liver, brain, or adipose tissue. A single blood value is therefore not always a good representation of the processes in the whole body.

A biomarker is not a guaranteed clinical benefit

An increase in NAD⁺, change in glutathione, or decrease in homocysteine can be biologically interesting. Nevertheless, it must be separately demonstrated whether such a change leads to a meaningful improvement in functioning, health, or quality of life.

Effects differ between people

Age, gender, genetic characteristics, nutrition, microbiome, health, medication, and baseline situation can all influence the response to an intervention.

The optimal dosage is often not established

A dose used in one study is not automatically the best or safest dose for long-term general use. Furthermore, a higher dosage is not necessarily more effective.

Life extension has not been demonstrated

There is no convincing evidence for NMN, GlyNAC, TMG, and similar supplements that they extend human lifespan. Claims about proven life extension go beyond what current human science supports.

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Lifestyle and healthy aging

Healthy aging is not determined by a single cellular pathway. Physical activity, dietary pattern, sleep, social circumstances, mental health, medical care, and the living environment all influence health and functioning.

The World Health Organization emphasizes, among other things, the importance of healthy nutrition and regular physical activity for maintaining physical and mental capacity. These are more broadly supported principles than the use of an individual longevity supplement.

Important points of attention are:

• exercising regularly and limiting prolonged sitting;
• sufficient sleep and a regular sleep rhythm;
• a varied dietary pattern with sufficient protein, fiber, and micronutrients;
• not smoking;
• limiting alcohol consumption;
• maintaining social contacts and mental activity;
• having risk factors and medical conditions assessed in a timely manner;
• sufficient recovery after physical and mental exertion.

Supplements cannot replace a healthy diet, exercise, sleep, and appropriate medical care.

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Which rules apply to supplements in the Netherlands and Europe?

There is no separate European product category for longevity supplements. In the European Union, these products fall under the general rules for food and dietary supplements. The Netherlands applies these European rules, and the Netherlands Food and Consumer Product Safety Authority (NVWA) supervises compliance.

The main European frameworks are:

• the European Directive on food supplements;
• the rules for food information and labeling;
• the regulation on nutrition and health claims;
• the Novel Food Regulation for new foods and ingredients.

These rules mean, among other things, that product information must not be misleading and that dietary supplements may not be presented as a means to prevent, treat, or cure a disease. For nutrition and health claims, work may only be done within the applicable European framework and the EU Register of nutrition and health claims.

The Netherlands, the EU, and Europe are not the same

A common basis applies within the EU, but rules for substances other than harmonized vitamins and minerals, notification procedures, and enforcement can differ per member state. A product offered in the Netherlands can therefore not automatically be sold in every other EU country without additional verification.

European countries outside the EU, such as the United Kingdom and Switzerland, have their own authorization, labeling, and claim rules. For cross-border sales, it must therefore always be checked which rules apply in the country of destination. “Available in Europe” is not a legal status.

For general Dutch information, you can consult the NVWA page on food supplements. At the European level, the EFSA and the European Commission provide information on safety, authorization, and claims.

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Assessing the quality of longevity supplements in the Netherlands and Europe

A professional website, high purity claim, or reference to research is not proof of quality in itself. When comparing longevity supplements, check whether the information on the label, the product page, and any certificate of analysis match each other.

1. Check the label and dosage

The label should clearly state which substance the product contains, how much of it is provided per capsule, measuring scoop, or daily dose, and which excipients have been used. Also pay attention to the batch number, the expiration date, storage advice, warnings, and the contact details of the responsible provider.

2. Look for batch-specific laboratory tests

A certificate of analysis, often called a CoA, is most informative when it belongs to the batch being sold. Check whether the batch number matches and whether the report actually measures the identity and quantity of the substance. Depending on the product, tests for heavy metals, microbiological contamination, and other relevant contaminants may also be important.

For NMN, HPLC is often used to assess identity and content. A percentage without mention of the test method, laboratory, analysis date, and batch number offers little verifiable information. See as an example how Every Day Better publishes the NMN certificates and independent tests.

For a product-specific check, also read how to compare an NMN supplement and what to look for when buying NMN.

3. Distinguish between an ingredient test and a finished product test

A report of the raw material is not always the same as an analysis of the final product. Therefore, check exactly what has been tested: the loose raw material, a capsule, the powder, or a complete product batch. Also check whether the mentioned laboratory is independent and recognizable.

4. Be critical of health claims

Claims such as “rejuvenates cells”, “stops aging”, or “proven to extend life” go beyond the available human evidence. In Europe, rules apply to nutrition and health claims. You can check permitted claims in the EU Register of nutrition and health claims.

5. Check the provider and the country of destination

A reliable provider makes it clear who is responsible for the product, how questions can be asked, and where information about shipping, returns, and product safety can be found. Additionally, check whether the product may be offered as a dietary supplement in the country of destination. A Dutch webshop and a Dutch-language label do not automatically mean that the product has the same status in all European countries.

The Netherlands Food and Consumer Product Safety Authority provides general information about dietary supplements and supervision in the Netherlands. The European Food Safety Authority explains how safety and scientific assessment are approached at the European level.

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Safety and responsible use

The fact that a substance is endogenous, natural, or scientifically researched does not automatically mean that extra intake is safe or necessary. Safety depends, among other things, on dosage, duration of use, product quality, health situation, and possible combinations with medications or other supplements.

Seek advice from a doctor or pharmacist before use in case of:

• pregnancy or breastfeeding;
• use by children or young people;
• medication use;
• a chronic or acute medical condition;
• kidney or liver problems;
• a planned surgery or treatment;
• unexplained or persistent complaints;
• combining multiple supplements.

Follow the recommended amount and warnings on the product label. Research dosages should not automatically be adopted as personal usage advice.

Do you use NMN or are you considering it? Then also read the extensive NMN package leaflet with safety information and points of attention.

This page is intended as general and educational information and does not constitute a diagnosis, treatment, or personal medical advice.

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Frequently asked questions about longevity supplements

What are longevity supplements?

Longevity supplements are dietary supplements being researched or offered in relation to healthy aging and underlying biological processes. It is not a legally defined quality category, and no supplement has been convincingly proven to extend human lifespan.

What does longevity mean at the cellular level?

Longevity at the cellular level is the study of biological processes in cells and tissues that can change during aging. Examples include mitochondrial function, energy metabolism, redox balance, methylation, and cellular maintenance.

Is longevity the same as living longer?

Not necessarily. Longevity literally means lifespan, but research also looks at healthspan: the period in which people remain relatively healthy and functional. A change in a biomarker does not prove that someone will live longer.

What are hallmarks of aging?

The hallmarks of aging are a scientific framework with which researchers organize different characteristics of biological aging. The framework includes genomic instability, epigenetic changes, mitochondrial dysfunction, cellular senescence, and changes in cell communication.

What do mitochondria do?

Mitochondria are involved in the production of ATP and various other processes, including calcium regulation, cell signaling, and responses to cellular stress.

Does NAD⁺ always decline with age?

No, this has not been convincingly demonstrated in humans in every tissue and with every measurement method. For example, a 2026 study found no age-related decline of NAD⁺ in whole blood. Human data therefore appear more complex and tissue-specific than is often suggested.

What does NMN have to do with NAD⁺?

NMN is an intermediate within pathways through which the body can form NAD⁺. Small studies show that NMN can increase measured NAD⁺ levels in blood, but that does not prove a slowing of aging or an extension of lifespan.

What does GlyNAC have to do with glutathione?

GlyNAC combines glycine and N-acetylcysteine. Glycine and cysteine are involved in the synthesis of glutathione. Human research into GlyNAC is interesting, but still limited in scope and duration.

What role does TMG play in methylation?

TMG, also known as betaine, can function as a methyl group donor. Via the enzyme BHMT, betaine is involved in the conversion of homocysteine to methionine.

Can NMN, GlyNAC, and TMG be used together?

The substances are studied from different biological processes, but the combination as a complete stack has not been sufficiently researched directly. A theoretical connection does not prove a synergistic health benefit.

What should you look for when buying longevity supplements in the Netherlands or Europe?

Check the exact substance and amount per dosage, excipients, warnings, batch number, shelf life, and provider details. A batch-specific report from a recognizable laboratory is more informative than just a standalone purity claim on the product page. Additionally, check the legal status in the country where the product is sold or delivered.

Do the same rules for supplements apply throughout Europe?

No. EU countries share a significant portion of food legislation, but national requirements, notification procedures, and enforcement can differ. European countries outside the EU have their own rules. Therefore, authorization or sale in one country does not automatically mean that sale is permitted in every European country.

What is the European Novel Food status of NMN?

The EU Novel Food Status Catalogue lists nicotinamide mononucleotide with a purity of 95–99% as a novel food for which no authorization has yet been included. The catalogue is a source of orientation and not a legally binding final decision for every individual product. Verification of the exact substance, application, and current status with the competent authority remains necessary.

Does a certificate of analysis prove that a supplement works?

No. A good certificate of analysis can provide information about identity, content, and tested contaminants. It does not prove that the product has a clinical effect, slows down aging, or extends lifespan.

Can supplements extend human lifespan?

There is no convincing evidence for NMN, GlyNAC, TMG, and similar supplements that they extend human lifespan.

Are cellular biomarkers the same as health?

No. Biomarkers can provide information about a biological process, but must be separately validated before they can be used as a reliable measure of health, biological age, or treatment outcome.

What is more important for healthy aging: lifestyle or supplements?

Nutrition, exercise, sleep, not smoking, social circumstances, and appropriate medical care have a broader foundation for healthy functioning during aging. Supplements cannot replace this basis.

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Further reading within Every Day Better

Main guides

• Overview and choice aid for NMN, GlyNAC, and TMG
• Practical explanation of cellular energy, recovery, and balance

NAD⁺ and NMN

• Complete NMN guide
• NMN and NAD⁺ explained
• Comparing NMN

Glutathione and GlyNAC

• Complete GlyNAC guide
• Comparing GlyNAC and NAC
• GlyNAC research

Methylation and TMG

• Complete TMG guide
• Comparing TMG and betaine
• Research into TMG

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Scientific and official sources

The sources below were used to verify the explanation of healthy aging, cellular processes, NAD⁺, GlyNAC, methylation, product quality, and European regulations.

1. World Health Organization. Healthy ageing and functional ability.
2. World Health Organization. Ageing and health.
3. López-Otín C. et al. Hallmarks of aging: An expanding universe.
4. Janssens G.E. et al. NAD⁺ precursor supplementation in human ageing: clinical evidence and challenges.
5. Trętowicz M.M. et al. Human whole-blood NAD⁺ levels do not vary with age or lifestyle interventions.
6. Igarashi M. et al. Chronic nicotinamide mononucleotide supplementation elevates blood NAD⁺ levels in healthy older men.
7. Kumar P. et al. Supplementing glycine and N-acetylcysteine in older adults.
8. Brosnan J.T. et al. Methylation demand: a key determinant of homocysteine metabolism.
9. Netherlands Food and Consumer Product Safety Authority. Food supplements.
10. European Food Safety Authority. Food supplements.
11. European Commission. EU Register of nutrition and health claims.
12. European Commission. EU Novel Food Status Catalogue: nicotinamide mononucleotide.
13. European Union. Directive 2002/46/EC on food supplements.
14. European Union. Regulation (EC) No 1924/2006 on nutrition and health claims.
15. European Union. Regulation (EU) No 1169/2011 on the provision of food information to consumers.
16. European Union. Regulation (EU) 2015/2283 on novel foods.

Last substantive check: July 21, 2026.