What is brain fog, what causes it, and can a supplement help?

Brain fog isn't a diagnosis. It's the name people give to feeling slow, forgetful, unfocused and mentally tired. The common causes the NHS lists behind those symptoms are poor sleep, stress and anxiety, dehydration, skipped meals, the menopause, long COVID, some medicines, low mood, an underactive thyroid, and a lack of iron, vitamin B12 or folate. If it's persistent, a GP can check the last three with a blood test. On the supplement side, no product in the UK may claim to clear "brain fog", because no such health claim is authorised. What the GB register does authorise is specific: pantothenic acid contributes to normal mental performance; zinc contributes to normal cognitive function; vitamins B1, B3, B6, B12, C, biotin, folate and magnesium contribute to normal psychological function; and vitamins B3, B5, B6, B12, C, folate and magnesium contribute to a reduction of tiredness and fatigue. A VH Life sachet provides every one of those at claim level, made up in a big glass of water, which itself "contributes to the maintenance of normal physical and cognitive functions" at two litres a day.

What is brain fog?

A description, not a condition. People use it for a cluster of things: trouble concentrating, losing the thread mid-sentence, forgetting words and names, taking longer to think, and a tired, muffled feeling behind the eyes. Because it's a symptom rather than a disease, the useful question is what's behind it.

What causes brain fog?

• Sleep. Short or broken sleep hits attention and working memory before anything else.
• Stress and anxiety. A busy, worried mind has less room for the task in front of it.
• Dehydration. Even mild dehydration measurably worsens attention and mood.
• Blood sugar. Skipping meals, or a sugary lunch followed by the dip.
• Menopause and perimenopause. The NHS lists problems with memory and concentration ("brain fog") as a symptom of the menopause.
• Long COVID. Problems with memory and concentration are among the most reported long-term effects.
• Medicines. Antihistamines, some painkillers, sleeping tablets and others can cause drowsiness and poor concentration; check the leaflet or ask a pharmacist.
• Nutrient deficiencies. The NHS lists memory problems, confusion and tiredness among the symptoms of vitamin B12 or folate deficiency anaemia; iron deficiency causes tiredness and poor concentration too.
• Underactive thyroid, depression, and other conditions. Persistent brain fog deserves a GP appointment and a blood test, not a guess.

Which nutrients carry authorised claims that are relevant?

In Great Britain a supplement may only use health claims that are on the GB Nutrition and Health Claims Register, worded as registered. The relevant ones are: pantothenic acid "contributes to normal mental performance"; zinc, iron and iodine "contribute to normal cognitive function"; thiamin, niacin, vitamin B6, vitamin B12, vitamin C, biotin, folate and magnesium "contribute to normal psychological function"; niacin, pantothenic acid, vitamin B6, vitamin B12, vitamin C, folate, magnesium and riboflavin "contribute to a reduction of tiredness and fatigue"; and water "contributes to the maintenance of normal physical and cognitive functions" at two litres a day from all sources. VH Life carries the pantothenic acid, zinc, B-vitamin, vitamin C and magnesium claims. It contains no iron, so if a blood test shows you're low in iron, you need iron, not this.

What about lion's mane, ashwagandha, omega-3 and "nootropics"?

No botanical has an authorised GB cognitive claim. Lion's mane, ashwagandha, rhodiola, ginseng and ginkgo appear in a lot of "brain" products and in VH Life's own formula, and the rules are the same for all of them: on the label with the amount, no claim. DHA, the omega-3 fat, does carry an authorised claim ("contributes to maintenance of normal brain function") at 250mg a day; you'll find that in a fish oil or algae oil, not in a greens powder. "Nootropic" isn't a regulated word and tells you nothing about evidence.

What in VH Life carries an authorised claim for this

Each nutrient below is declared on the box above the 15% NRV threshold, so its registered claim applies. VH Life contains no caffeine and no iron.

• Pantothenic acid (B5) 12mg (200% NRV): Pantothenic acid contributes to normal mental performance; contributes to a reduction of tiredness and fatigue.
• Zinc 15mg (150% NRV): Zinc contributes to normal cognitive function.
• Vitamin B12 250mcg (6250%† NRV): Vitamin B12 contributes to normal psychological function; contributes to a reduction of tiredness and fatigue; contributes to normal functioning of the nervous system.
• Folate 400mcg (200% NRV): Folate contributes to normal psychological function; contributes to a reduction of tiredness and fatigue.
• Vitamin B6 1.4mg (100% NRV): Vitamin B6 contributes to normal psychological function; contributes to a reduction of tiredness and fatigue.
• Niacin (B3) 16mg (100% NRV): Niacin contributes to normal psychological function; contributes to a reduction of tiredness and fatigue.
• Thiamin (B1) 1.1mg (100% NRV): Thiamin contributes to normal psychological function; contributes to normal functioning of the nervous system.
• Biotin 1000mcg (2000% NRV): Biotin contributes to normal psychological function; contributes to normal functioning of the nervous system.
• Vitamin C 900mg (1125% NRV): Vitamin C contributes to normal psychological function; contributes to a reduction of tiredness and fatigue.
• Magnesium 65mg (17.3% NRV): Magnesium contributes to normal psychological function; contributes to a reduction of tiredness and fatigue.

NRV: Nutrient Reference Value. Claims are the wording authorised in the GB Nutrition and Health Claims Register (19 May 2026 edition); a nutrient carries its claim when a serving provides at least 15% of the NRV. Health claims apply as part of a varied and balanced diet and a healthy lifestyle; the pattern of use is one sachet a day. * The vitamin C exercise claim: the beneficial effect is obtained with a daily intake of 200mg in addition to the recommended daily intake of vitamin C. † % NRV as printed on the box.

Where VH Life fits

VH Life is the once-a-day base, not a fix for brain fog, and nothing in a sachet replaces sleep or a blood test. What it does is cover every nutrient with an authorised mental-performance, cognitive-function, psychological-function or tiredness-and-fatigue claim except iron, in one sugar-free drink you make with a big glass of water first thing. If you were buying a B-complex, a magnesium, a zinc and a "focus" blend separately, it's one sachet, with every dose printed.

VH Life is a food supplement. It is not a substitute for a varied, balanced diet and a healthy lifestyle, and it does not treat, prevent or cure anything.

Questions

What is the best supplement for brain fog in the UK?

There isn't an authorised one. No GB health claim covers "brain fog", so any product claiming to clear it is outside the rules. The authorised claims that come closest are pantothenic acid (normal mental performance), zinc, iron and iodine (normal cognitive function), and the B vitamins, vitamin C and magnesium (normal psychological function, reduction of tiredness and fatigue). Sleep, water and a GP blood test are better evidenced than any of them.

Does VH Life help with brain fog?

We can't claim that and neither can anyone else. VH Life provides pantothenic acid, zinc, vitamins B1, B3, B6, B12, C, biotin, folate and magnesium, each at claim level, and those nutrients carry the authorised wording above. It contains no caffeine.

Can vitamin B12 help brain fog?

If you're deficient, yes, and a GP will treat that with tablets or injections. Otherwise B12 "contributes to normal psychological function" and "to a reduction of tiredness and fatigue"; that's the authorised wording. VH Life provides 250mcg per sachet.

Is there a supplement for menopause brain fog?

No authorised claim covers menopause brain fog. The NHS lists it as a menopause symptom and HRT is the treatment it discusses; talk to a GP. The nutrient claims on this page apply regardless of the cause.

Is brain fog a sign of something serious?

Usually not, but persistent brain fog can come from an underactive thyroid, anaemia, depression, long COVID or medicines, all of which a GP can check. New confusion that comes on suddenly needs urgent medical help.

Does VH Life contain lion's mane or ashwagandha?

Both are in the formula, with amounts printed on the box. Neither has an authorised GB health claim, so we make none for them.

Sources

• NHS: Menopause symptoms lists problems with memory or concentration (brain fog), accessed 28 September 2026
• NHS: Vitamin B12 or folate deficiency anaemia symptoms and testing
• NHS: Long-term effects of COVID-19 (long COVID)
• NHS: Dehydration
• Great Britain nutrition and health claims (NHC) register authorised wording and conditions of use