Supplements for Focus and Concentration: Which Nutrients Have Authorised Claims?

Why is concentration so difficult to maintain?

Most people experience periods where focus feels elusive. Deadlines pass without progress, reading the same paragraph three times becomes routine, and the mental clarity that once came naturally seems to have quietly disappeared.

The causes are varied. Poor sleep, chronic stress, excessive screen time, hormonal shifts, medication side effects, and underlying medical conditions — including ADHD and other neurodevelopmental conditions — can all impair concentration. If you have or suspect you have ADHD, speak to your GP; this article does not address the management of any medical condition. It covers one specific and often overlooked angle: the role of nutrition.

Several vitamins and minerals carry EU-authorised health claims for cognitive function, psychological function, and nervous system function. When intake of these nutrients falls below adequate levels, concentration can suffer — and unlike many other causes of poor focus, nutritional gaps are measurable and correctable.

If you are experiencing persistent cognitive difficulties, speak to your GP. This article covers nutritional factors only and is not a substitute for medical advice.

Which nutrients carry EU-authorised cognitive function claims?

Under EU Regulation 432/2012, retained in UK law post-Brexit, three nutrients carry the specific authorised claim "contributes to normal cognitive function":

Iron — required for oxygen transport to the brain and neurotransmitter synthesis
Zinc — involved in synaptic signalling and neurotransmitter regulation
Iodine — essential for thyroid hormone production, which regulates cerebral metabolism

This is the complete list. No other vitamin, mineral, herb, or compound is legally permitted to make this specific claim in the UK. Many supplement brands imply their products "boost" or "enhance" cognitive function — language that is neither authorised nor accurate.

A broader set of nutrients carries claims for "normal psychological function" and "normal functioning of the nervous system" — both of which are relevant to concentration. These are covered in the sections below.

How does iron deficiency affect concentration?

Iron contributes to normal cognitive function, normal oxygen transport in the body, and normal energy-yielding metabolism — all authorised EU health claims.

The mechanism is direct. Iron is a component of haemoglobin, which delivers oxygen to the brain. The brain accounts for roughly 20% of the body's total oxygen consumption despite representing only 2% of body mass. When iron status is low, oxygen delivery to neural tissue is impaired, and cognitive performance declines — often before anaemia is formally diagnosed.

Iron deficiency is the most prevalent nutritional deficiency worldwide, and UK data confirms it is common domestically. The National Diet and Nutrition Survey (NDNS) shows that 49% of girls aged 11-18 and 25% of women aged 19-64 have iron intakes below the Lower Reference Nutrient Intake (LRNI).

Murray-Kolb & Beard (2007) demonstrated the cognitive impact in a double-blind, placebo-controlled trial of 149 young women. Those with iron deficiency who received iron supplementation showed significant improvements in cognitive performance — specifically in attention, memory, and learning tasks — compared to placebo. The improvements were proportional to the improvement in iron status.

Iron deficiency is one of the most common and correctable nutritional causes of poor concentration. If your focus has declined and your diet is low in red meat, pulses, or fortified cereals, iron status is worth investigating. For a detailed comparison of supplemental iron forms, see our guide to iron supplements.

What role do B vitamins play in brain function?

Multiple B vitamins carry authorised claims directly relevant to concentration and mental performance. The claims fall into two categories:

"Contributes to normal psychological function" — Vitamin B1, Vitamin B6, Vitamin B12, Niacin (B3), Biotin, Folate, and Vitamin C

"Contributes to the normal functioning of the nervous system" — Vitamin B1, Vitamin B6, Vitamin B12, Niacin, Biotin, Magnesium

"Contributes to normal mental performance" — Pantothenic acid (B5)

B5 is the only nutrient that carries this specific mental performance claim — making it uniquely relevant to anyone seeking nutritional support for focus.

B vitamins function as coenzymes in the metabolic pathways that produce neurotransmitters (including acetylcholine, dopamine, serotonin, and GABA), maintain myelin sheaths around nerve fibres, and generate the cellular energy that neurons require to fire efficiently. These roles are interconnected — a shortfall in any single B vitamin can create a bottleneck that affects the others.

Kennedy (2016) argued in a comprehensive review that research has historically focused narrowly on B12, folate, and B6 through the lens of homocysteine metabolism, while the broader cognitive roles of all eight B vitamins have been underappreciated. The review concluded that adequate status across the full B-vitamin spectrum is more relevant to brain function than high-dose supplementation of any single B vitamin.

This has practical implications. If you supplement B12 alone but your folate or B6 status is also suboptimal — which NDNS data suggests is common — you may not address the underlying nutritional gap. A complete B-vitamin profile matters more than megadosing one.

Does magnesium support cognitive performance?

Magnesium contributes to normal psychological function and contributes to the normal functioning of the nervous system — both authorised EU health claims.

Magnesium is a cofactor in over 300 enzymatic reactions, including those involved in neurotransmitter release, synaptic plasticity, and the regulation of the hypothalamic-pituitary-adrenal (HPA) axis. When magnesium is insufficient, the nervous system becomes more excitable, stress responses are amplified, and the calm, sustained attention required for concentration is harder to achieve.

Boyle et al. (2017) conducted a systematic review examining magnesium supplementation and subjective measures in stressed adults. The review found suggestive evidence that magnesium supplementation may benefit individuals with low magnesium status, particularly those under chronic stress — a state that is itself a significant contributor to poor concentration.

NDNS data shows that up to 53% of adolescent girls and 19% of young adults aged 20-29 fall below the LRNI for magnesium. Chronic stress, alcohol consumption, and diets low in green leafy vegetables, nuts, and wholegrains further deplete magnesium stores.

The overlap between stress, poor sleep, and impaired concentration is well established. If your focus difficulties coincide with stress or fatigue, magnesium status is worth considering. See our articles on supplements for tiredness and fatigue and supplements for stress and anxiety for related evidence.

What does the evidence say about ashwagandha and cognitive function?

Ashwagandha (KSM-66®) does not hold an EU-authorised health claim for cognitive function, psychological function, or any other health outcome. That needs to be stated clearly. What follows is clinical trial evidence, not a regulatory approval.

KSM-66® is a standardised root extract of Withania somnifera and the most extensively studied form of ashwagandha. Its traditional classification as an adaptogen — a botanical that may help the body manage stress — has led to modern clinical investigation of its cognitive effects.

Choudhary et al. (2017) conducted a prospective, randomised, double-blind, placebo-controlled trial in 50 healthy adults. Participants received either 300 mg KSM-66® ashwagandha root extract twice daily or placebo for 8 weeks. The ashwagandha group showed significant improvements in both immediate and general memory, as well as improvements in executive function, sustained attention, and information-processing speed compared to placebo.

These results are promising, but context is important. The sample size was small, the study was conducted in a single centre, and the findings require replication in larger, multi-centre trials before strong conclusions can be drawn. Ashwagandha is not a substitute for medical assessment of cognitive difficulties, and its mechanism of action — thought to involve modulation of cortisol and GABAergic signalling — is not fully established.

PARTICULAR includes KSM-66® ashwagandha — the same standardised extract used in these clinical trials — when your questionnaire responses indicate it may be relevant to your profile.

Nutrients with cognitive and psychological function claims

Nutrient	EU-authorised claim	Form in PARTICULAR	Key dietary sources
Iron	Contributes to normal cognitive function	Ferrous Gluconate	Red meat, lentils, fortified cereals
Zinc	Contributes to normal cognitive function	Zinc Bisglycinate	Meat, shellfish, pumpkin seeds
Iodine	Contributes to normal cognitive function	Fucus vesiculosus L. Extract	Dairy, fish, seaweed
Magnesium	Contributes to normal psychological function	Magnesium Citrate	Dark leafy greens, nuts, seeds
Vitamin B6	Contributes to normal psychological function	Pyridoxine Hydrochloride	Poultry, fish, potatoes
Vitamin B12	Contributes to normal psychological function	Methylcobalamin	Meat, fish, dairy (absent from plant foods)
Vitamin B1	Contributes to normal psychological function	Thiamin Hydrochloride	Wholegrains, pork, legumes
Niacin (B3)	Contributes to normal psychological function	Nicotinamide	Poultry, fish, wholegrains
Biotin	Contributes to normal psychological function	D-Biotin	Eggs, nuts, seeds
Folate	Contributes to normal psychological function	L-5-MTHF	Dark leafy greens, legumes, fortified cereals
Vitamin C	Contributes to normal psychological function	L-Ascorbic Acid	Citrus fruits, peppers, berries
Pantothenic acid (B5)	Contributes to normal mental performance	Calcium D-Pantothenate	Meat, avocado, wholegrains

Can diet alone support cognitive function?

In principle, yes. The nutrients listed above are all obtainable from a well-planned diet. Iron-rich foods include red meat, lentils, and fortified cereals. Zinc is found in meat, shellfish, and pumpkin seeds. Iodine sources include dairy, fish, and seaweed — though iodine intake is notably inconsistent in the UK, particularly among those who avoid dairy.

In practice, UK dietary data tells a different story. The NDNS consistently reveals significant shortfalls across multiple nutrients relevant to cognitive function:

Iron: 49% of girls aged 11-18 and 25% of women aged 19-64 fall below the LRNI
Magnesium: up to 53% of adolescent girls fall below the LRNI
Folate: more than half of 11-18 year-olds have serum folate concentrations below the threshold indicating possible deficiency
Iodine: studies have found mild-to-moderate iodine deficiency in UK schoolgirls and pregnant women

These are not edge cases. They describe a substantial portion of the population whose dietary intake is insufficient to support the nutrient levels required for the authorised cognitive and psychological function claims described in this article.

Diet should always be the foundation. But when dietary gaps persist — whether due to food preferences, lifestyle, absorption issues, or increased requirements — targeted supplementation provides a practical route to adequate intake.

How does PARTICULAR approach cognitive nutrition?

PARTICULAR is not a cognitive enhancement product. It does not claim to make you sharper, faster, or more focused. What it does is identify potential nutritional gaps through a detailed questionnaire — 26 questions covering diet, lifestyle, health goals, sleep, stress, and other factors — and formulate a personalised supplement that addresses those gaps.

The questionnaire uses 74 scoring rules across 5 dimensions to determine which of 30+ nutrients are relevant to your individual profile. If your responses indicate a diet low in iron-rich foods, limited dairy intake (affecting iodine), high stress levels, or other factors associated with suboptimal status of the nutrients covered in this article, your formulation will include them at evidence-based doses.

Every ingredient is delivered as vegan microgranules manufactured in a GMP-certified facility in Germany. The forms used — Ferrous Gluconate, Zinc Bisglycinate, Methylcobalamin, L-5-MTHF, Magnesium Citrate, and KSM-66® ashwagandha among others — are chosen for bioavailability and tolerability.

The approach is simple: ensure adequate intake of the nutrients that carry authorised claims for cognitive function, psychological function, nervous system function, and mental performance — personalised to what your diet and lifestyle may be missing.

Take the questionnaire to see what your formulation would include, or visit our science page for more on how the personalisation algorithm works.

Key takeaways

Three nutrients carry the EU-authorised claim "contributes to normal cognitive function": iron, zinc, and iodine. A broader set of B vitamins, magnesium, and vitamin C carry claims for normal psychological function and nervous system function.
Iron deficiency is the most common and correctable nutritional cause of poor concentration. Nearly half of teenage girls and a quarter of adult women in the UK have iron intakes below the LRNI.
B vitamins work synergistically — supplementing one in isolation is less effective than ensuring adequate status across the full spectrum. Pantothenic acid (B5) uniquely carries the claim "contributes to normal mental performance."
Magnesium contributes to normal psychological function and normal functioning of the nervous system. Deficiency is common, particularly in younger adults and those under chronic stress.
Ashwagandha (KSM-66®) does not hold an authorised health claim, but clinical trial evidence suggests it may support memory and cognitive task performance. The research is promising but requires further replication.
UK dietary data from the NDNS consistently shows significant shortfalls in iron, magnesium, folate, and iodine — nutrients directly relevant to the cognitive and psychological function claims described above.
Diet should be the foundation for adequate nutrient intake, but when gaps persist, targeted supplementation provides a practical and evidence-based route to adequate status.
Supplements are not cognitive enhancers. They support normal function by ensuring the body has adequate levels of the nutrients required for the brain and nervous system to work as they should.
If you are experiencing persistent difficulties with concentration, memory, or cognitive function, consult your GP. Nutritional factors are one piece of a much larger picture, and professional assessment is essential to rule out underlying conditions.

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