Beyond herbs, a number of nutrients may work as brain boosters.

An omega-3 fatty acid found in fish oils, docosahexaenoic acid (DHA) is thought to be important to an infant’s developing brain. DHA may also work as a brain booster by helping brain cells communicate, according to Sahelian.

“Interestingly, the lining of our brain cells is very highly concentrated with fatty acids, particularly DHA,” he says.

One 1999 review of studies on DHA, published in the journal Pharmacological Research, found that the nutrient is essential to normal brain function and that a diet rich in DHA improves learning, while a lack of DHA causes learning ability to suffer.

“Another one that I really like is aceytl-L-carnitine. That’s becoming quite popular,” Sahelian says.

Acetyl-L-carnitine may work as a brain booster by helping maintain brain cells. Not much is known about its effects in healthy people, but one study found that people with early Alzheimer’s and mild memory impairment benefited from taking it.

Despite the lack of evidence, Sahelian says he thinks it improves mental focus and alertness. “I noticed the effect within two hours,” he says. “It also makes one more motivated, and you can concentrate better and get things done faster.”

DMAE (2-dimethylaminoethanol), also thought to alter levels of acetylcholine in the brain, is another one that Sahelian says he can get behind based on anecdotal evidence alone. There is little in the way of scientific data to support claims that it boosts brainpower.

Nevertheless, “Most people will notice within an hour or two of taking it that they’re thinking faster and sharper and that they have better focus,” he says.

He says that taking too much can cause side effects such as restlessness, irritability, and tension in the neck muscles.