Nicotine’s Effects on the Brain & Body & How to Quit Smoking or Vaping

Andrew Huberman, introducing himself as a professor of neurobiology and ophthalmology at Stanford School of Medicine, opens with how widely nicotine is used: billions of people take it in every day, most of them by smoking tobacco. Tobacco contains nicotine along with many other substances, and burning it frees the nicotine so the body's cells and tissues can absorb it. The episode also lists other routes. Dip places tobacco inside the lip or cheek. Snuff puts tobacco up the nostrils, where nicotine passes through the soft mucosal lining of the nasal passages.

Patches, gum, pills and nicotine-dipped toothpicks complete the list. The main framing move is to discuss nicotine apart from its delivery method. Smoking and vaping come up both for their harms and, in what the host stresses are "very specific certain cases," for possible health benefits of delivering nicotine through particular modalities. He says plainly that those beneficial modalities do not include smoking cigarettes or vaping. Vaping gets extra attention because its use is rising, especially among young people. The host's argument is that the high nicotine content of vaping products, together with nicotine's effects on brain chemistry, can drive addiction to other substances and behaviours associated with vaping.

we really need to separate out a discussion about nicotine from the discussion about the delivery device for nicotine.

The host returns to this distinction before the core science. Smoking, vaping and other delivery methods have their own effects, mostly negative but in some cases positive, separate from nicotine itself. He also previews a point he expects to surprise listeners: many people use nicotine or nicotine-like substances to get over nicotine addiction. Protocols for this are promised for later in the episode.

Before turning to nicotine, the host recaps an earlier toolkit episode on focus. He presents it as groundwork for explaining why nicotine increases focus so effectively. He picks two protocols out of the many behavioural, pharmacologic and other interventions covered there. The first comes from studies in Wendy Suzuki's lab at New York University, which the host says show that a daily 13-minute meditation can greatly increase focus, both right after the practice and at other times.

The method is simple. Sit or lie down, close your eyes, and direct attention to a spot just behind the forehead, roughly an inch behind it and slightly above the point between the eyes. The brain has no sensory receptors, so the only thing you can sense there is your own thoughts. According to the host, the benefit comes from repeatedly bringing attention back to that spot after it drifts. He recommends doing it daily but says a missed day is no reason to despair. He adds that the data also show benefits for mood and other aspects of mental health and performance.

The second tool is a conceptual model the host built to simplify the large body of research on the neurochemistry of focus. He sets up its three chemicals as background for the nicotine discussion that follows.

Arrowhead: acetylcholine, which sets the direction of focus. Shaft: epinephrine, also called adrenaline (the same neurochemical, usually called epinephrine in the brain and adrenaline in the body), which supplies the energy to focus. Propeller or motor: dopamine, which provides ongoing motivation and keeps pushing the arrow forward.

In this model, raising acetylcholine, epinephrine and dopamine at the same time improves focus. The host names alpha-GPC as one supplement-based way to do this: 300 milligrams taken 10 to 30 minutes before a bout of cognitive or physical work. He says it raises acetylcholine and, to some extent, epinephrine. Dopamine would have to come from elsewhere, such as self-talk, since he says thoughts do affect dopamine levels, or from other dopamine-increasing protocols covered in earlier episodes.

The supplement recommendation comes with several qualifications. The host says no one needs to take alpha-GPC. He notes it can raise TMAO, which he describes as a negative marker of cardiac and cardiovascular health, and says that he and many others take a 600-milligram garlic capsule to offset this. He also admits it is uncertain how much alpha-GPC it takes for TMAO to rise to a level of concern. He discourages taking it every time one wants to focus, and puts behavioural tools first, nutritional tools second and occasional supplements third.

Prescription compounds such as Ritalin, Adderall, modafinil, armodafinil and Vyvanse are mentioned as options a board-certified physician might prescribe. The host says these may be important or even necessary for people with ADHD, but he treats them as a separate category. He repeats that he is not a physician and does not prescribe anything. He also calls both protocols optional. Their main use for this episode is to establish the roles of acetylcholine, epinephrine and dopamine, which he says explain why nicotine boosts focus, motivation, working memory and cognitive capacity.

The host says he has had a long-standing interest in nicotine. Early in his scientific career he researched nicotine's role in brain development, and he has long been interested in neuroplasticity. He cites experiments by close colleagues showing that acetylcholine acting on nicotinic receptors can act as a gateway or trigger for directed rewiring of the brain. His conceptual point is that these receptors did not evolve because tobacco, vape pens or anything else in the outside world exists. Their presence in the brain and body shows that acetylcholine and nicotine have important roles in normal function.

To illustrate, the host tells a story about a well-known, Nobel Prize-winning neuroscientist whom he does not name, other than saying the person is a man and not on the Stanford faculty. During a conversation of about 45 minutes, this scientist chewed at least three pieces of nicotine gum. He explained that years of chronic smoking had greatly impaired his cardiovascular health and fitness. He kept using nicotine gum because, as he described it, data suggested nicotine might protect against some forms of cognitive impairment, and he valued its effects on focus and motivation.

The host is clear about smoking: in his words, there is "simply no question" that it harms lung health. While some ways of smoking are more or less unhealthy than others, he says any smoking disrupts lung endothelial function, lung function and blood vessels, and makes it harder to breathe deeply and deliver oxygen to tissues. He also says the anecdote is "not a call to arms" to start using nicotine products. He admits he has not checked in with the scientist for some years. So he cannot say whether nicotine has helped ward off Alzheimer's or other age-related decline. The man still seems sharp, he adds, but was always exceedingly sharp.

The point is, nicotine is a substance that can both promote cognitive function and, under some conditions, if taken to inappropriate, or I should say to extreme dosages, can also impair cognitive function.

From this, the host calls for a nuanced discussion that covers drawbacks for particular groups: children, people who are pregnant, people with addictive tendencies, and people with depression or other mood disorders. He also previews that nicotine is a strong mood modulator. Many people trying to quit, mostly smokers, find that their mood drops substantially.

Nicotine is best known from the tobacco plant. It also occurs in nightshades such as tomatoes, eggplants and sweet peppers, and in potatoes, but at much lower concentrations than in tobacco. The host describes it as a plant alkaloid. He gives the evolutionary explanation as a hypothesis: alkaloids are "thought" to have evolved to stop insects from eating plants. The supporting evidence is that nicotine is used as a pesticide. It can severely disrupt insects' nervous systems, impair their motor and brain function, kill them, or make them infertile.

The host twice stresses that nicotine does not make humans infertile. He attributes the different effects in humans to differences in the type and location of nicotine receptors. He does flag a human concern for later: double-blind, peer-reviewed studies indicating that nicotine can reduce penile girth and contribute to certain forms of sexual dysfunction. He describes these changes as largely downstream of effects on blood flow and endothelial cells, the cells that make up blood vessels and other vascular tissue.