Every year, Americans spend over $3.56 billion on supplements that claim to enhance focus, improve memory, and guard against dementia.

However, medical experts caution that some of the most popular and affordable “brain boosters” might actually have adverse effects, potentially accelerating the brain’s aging process.

Three U.S. physicians have identified six specific supplements or combinations that could jeopardize mental capabilities.

Among these is vitamin E, commonly believed to protect neurons, but which the doctors suggest might lead to brain hemorrhages. Additionally, popular wellness supplements like ashwagandha and turmeric, often used to reduce inflammation, could result in harmful waste accumulation in the blood.

The physicians also advise against combining fish oil with ginkgo and garlic, as this could increase the risk of brain bleeding. They caution that starting the day with both coffee and a stimulant may cause anxiety or migraines in some individuals.

Furthermore, the doctors recommend avoiding the combination of zinc and copper, as these minerals offer no significant brain benefits. They also warn against kratom, an herb purported to enhance brain health, but which the FDA has flagged for potentially increasing hospitalization risks.

Dr Jerold Fleishman, a neurologist at MedStar Georgetown University Hospital, warned: ‘The general principle emerging from the literature is that indiscriminate supplementation, particularly with isolated nutrients at high doses or in unbalanced combinations, may be more problematic than beneficial. 

‘There is limited evidence specifically documenting harmful combinations of supplements for brain health, as most trials rarely reported adverse events in detail.’

Doctors have warned over six common supplements or supplement combinations that they say could age the brain more rapidly (stock image)

He added, while speaking to health publication Parade: ‘However, certain combinations and individual supplements warrant caution based on available data.’

About a quarter of Americans over 50 years old take brain supplements, particularly driven by concerns over cognitive decline.

But the three doctors said the best way to protect the brain was to eat healthy, exercise, socialize, sleep well and keep challenging themselves, alongside reducing alcohol intake.

Supplements should only be an addition on top of this, they added, and that it was best to take them after a blood test showed they had a deficiency in the substance that they were supplementing for.

Below are the six supplements the doctors warned against:  

Vitamin E

About one in 10 adults takes vitamin E daily, estimates suggest, to help protect the brain and other parts of the body from damage. 

The vitamin is a powerful antioxidant, and researchers say it can neutralize chemicals that would otherwise damage cells. In the brain, there are even some papers suggesting that taking vitamin E may slow mild to moderate Alzheimer’s disease.

But a major 2024 review of 48 studies on the vitamin led by US scientists found there was no concrete evidence that it could slow brain aging, and called for more research.

Other scientists have also noted that supplements tend to contain a high dose, containing around 1,200 percent of someone’s daily needs, and warn that these high levels could raise the risk of a bleed in the brain. 

Among them was vitamin E, which they said could inhibit blood clot formation in rare cases and raise the risk of a brain bleed (stock image)

They said vitamin E can inhibit the formation of blood clots that would block a bleed, and warned that if a bleed occurred, it would damage the brain, and cause it to age.

Some research has also warned that taking a vitamin E supplement raises the risk of prostate cancer in men, which could lead to treatment with hormone drugs that may also damage the brain. 

Turmeric and ashwagandha

Many Americans take turmeric and ashwagandha because of their claims they can lower inflammation, which could also potentially boost memory and cognitive function.

But Dr William Scott Burin, a neurologist at the University of South Florida, warned that the supplements could also lead to brain-damaging substances building up in the blood.

Both supplements are normally taken in high doses, which can overload the liver — the organ that breaks them down — and cause it to become inflamed and work less effectively.

As a result, the liver is left struggling to filter waste products out of the blood, which build up and then may disrupt communication between neurons, causing symptoms that appear to be cognitive decline.

Burin said the side-effect was not common, although it has been reported in some cases, including a woman in New Jersey who, last year, was hospitalized after she took high-dose turmeric.

Fish oil with gingko, garlic or turmeric  

About one in five US adults over 60 take fish oil, which some studies suggest, among other health benefits, could boost learning and memory because it provides the building blocks for maintaining neurons.

There were also warnings over turmeric, which some studies suggest can boost brain health by slashing inflammation levels (stock image)

These individuals may also take Ginkgo, made from the gingko tree, which studies suggest may prevent memory loss, turmeric, or garlic, which could also reduce brain inflammation. 

But Fleishman warned that taking two or more of these supplements together could raise the risk of the brain being damaged or aged.

He said: ‘The worst combinations are the ones that raise bleeding risk or trigger dangerous stimulation.

‘A common risky stack is high dose fish oil plus gingko plus garlic or turmeric, especially if the person also takes aspirin, clopidogrel, warfarin or apixaban, because it can increase bruising and bleeding risk.’

Doctors warn fish oil can raise the levels of nitric oxide in the blood, which blocks platelet formation, while ginkgo, turmeric and garlic can also slash these levels, which raises the risk of a brain bleed. Bleeding on to the brain causes damage that can raise the organ’s age.

The risk of this is generally low, however, the doctors said, although they warned patients to consult with their physician.

Zinc and copper

People take zinc for brain health because it may help support the growth of new neurons, and take copper because it may help the body to make more chemicals, allowing for communications between neurons. 

These effects help to boost memory, cognitive function and reduce cognitive decline.

But Dr Fleishman warned that there was no concrete evidence that the supplements improved brain health, while cautioning they may come with hidden risks.

He said: ‘While not specifically harmful, the lack of benefit combined with potential for mineral imbalances suggests caution with this combination.’

Zinc supplements often contain 30mg per pill, or nearly three times someone’s daily needs, while copper supplements contain 2mg, or two times someone’s daily needs. 

Coffee with stimulants

Coffee is an extremely popular drink in the US, with about three in four people starting their day with the drink.

But the doctors warned that if someone had coffee alongside yohimbine, a supplement that may boost feel-good hormones in the brain, or synephrine, a supplement popular with athletes that can boost focus, they may raise the risk of aging their brain.

The doctors also said that having coffee and a supplement that is also a stimulant may also damage brain health (stock image)

Dr Rab Khan, a neurologist at Northwell Health, warned: ‘Another bad mix is multiple stimulants, like high caffeine with yohimbine, synephrine or high-dose green tea extract, because it can worsen anxiety, insomnia, palpitations and migraines.’

Scientists warn that worsened anxiety, insomnia or migraines can disrupt sleep, which studies show has a negative impact on brain health.

Kratom

More than a million Americans are estimated to take the stimulant Kratom amid reports it can ease pain, mood and boost energy and focus.

Many assume it is safe because it is made from a plant, but doctors warned that the supplement — made from the powdered leaves of the kratom tree — could harm brain health.

They said it had not been found to be safe in any medical trial, while the FDA has warned people not to take the supplement and said it is ‘of concern’.

They also warned that, at higher doses, the supplement may disrupt communication between nerves, raising the risk of cognition and mood issues.

Side effects of kratom include dry mouth, weight loss, nausea and vomiting, constipation, liver damage and high blood pressure. 

Do any supplements actually help the brain?

The three doctors underlined that the most important thing to do to protect brain function was to eat healthily, exercise, sleep well, socialize and engage in cognitively challenging tasks.

They added that keeping alcohol intake modest and treating hearing loss would also help.  

They said anyone with concerns over their mental abilities should see their doctor first rather than turning to a supplement.

Overall, they said there was no reliable evidence that brain supplements work. But, they could be taken as an optional extra if someone had a blood test that showed a particular deficiency.