Nicotine: it works - by Sebastian Jensen - Technotheoria
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Nicotine: it works<br>3-8 IQ point gain, no dose response relationship beyond 1mg
Sebastian Jensen<br>Jul 23, 2026
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Most of the negative health effects of smoking do not come from nicotine itself. Very few people get addicted to nicotine in the form of gum. As such, nicotine could potentially be used as a stimulant or nootropic, the same way people use caffeine or amphetamines.<br>In the scientific literature, what caught my attention was a large meta-analysis on the effect of nicotine on cognitive performance. It was incorrectly executed, so I decided to run on my own. Several of the studies reported multiple effect sizes from multiple groups, so I tracked them. I divided the sample sizes by the number of effect sizes that were reported for each individual group, to get an estimate of the effective sample size of each study.<br>The aggregate effect size is about 0.38 SD, translating to 6 IQ points.
There is no dose-response relationship.
The quick-and-dirty meta-analytic effect is 0.33. The existence of it was extremely unambiguous (p Random-Effects Model (k = 84; tau^2 estimator: REML)
logLik deviance AIC BIC AICc<br>-53.6688 107.3375 111.3375 116.1752 111.4875
tau^2 (estimated amount of total heterogeneity): 0.1178 (SE = 0.0320)<br>tau (square root of estimated tau^2 value): 0.3432<br>I^2 (total heterogeneity / total variability): 62.10%<br>H^2 (total variability / sampling variability): 2.64
Test for Heterogeneity:<br>Q(df = 83) = 255.1649, p-val
I tested for moderators; none of them were significant in the aggregate : dose, smoking status, or domain of cognition.<br>Mixed-Effects Model (k = 84; tau^2 estimator: REML)
logLik deviance AIC BIC AICc<br>-46.0473 92.0946 116.0946 143.5801 121.2946
tau^2 (estimated amount of residual heterogeneity): 0.1155 (SE = 0.0342)<br>tau (square root of estimated tau^2 value): 0.3399<br>I^2 (residual heterogeneity / unaccounted variability): 60.32%<br>H^2 (unaccounted variability / sampling variability): 2.52<br>R^2 (amount of heterogeneity accounted for): 1.91%
Test for Residual Heterogeneity:<br>QE(df = 73) = 216.0037, p-val
I averaged all of the effect sizes of the individual publications to estimate publication bias. The regression test suggested that if there was any publication bias, it was likely negative — people wanted to report nulls more than positive effects.<br>#Meta-analysis with aggregated effect sizes<br>Random-Effects Model (k = 41; tau^2 estimator: REML)
logLik deviance AIC BIC AICc<br>-18.3017 36.6034 40.6034 43.9812 40.9278
tau^2 (estimated amount of total heterogeneity): 0.1088 (SE = 0.0344)<br>tau (square root of estimated tau^2 value): 0.3299<br>I^2 (total heterogeneity / total variability): 75.42%<br>H^2 (total variability / sampling variability): 4.07
Test for Heterogeneity:<br>Q(df = 40) = 182.8701, p-val 0): b = 0.4960 (CI: 0.0497, 0.9422
So, it does seem that the effect of nicotine on intelligence is real, just not exciting — maybe an increase of 3-8 IQ points. I should note that, if the effect is indeed generalised. The effects of it on real world outcomes and broader cognitive function haven’t been studied very well, so it’s difficult to tell how much the cognitive enhancement generalises.<br>Other notes
Nicotine, through smoking, increased performance on the Raven’s test by 6 IQ points, but the effect barely passed significance testing.
Nicotine reduces insepction time by about 0.5 SD (good), and the study had low p-values in the 0.001-0.01 range. Seems legit.
One study claims nicotine increases mental speed, but not performance on intelligence tests. I’m not inclined to put much weight into this finnding, as they had just 55 subjects. The effects of amphetamines on IQ/SAT type tests, for example, are very small (d = 0.05-0.15), but probably real.
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Discussion about this post<br>CommentsRestacks
Steveo<br>Jul 24
Liked by Sebastian Jensen
Isn’t no dose response a huge red flag?
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1 reply by Sebastian Jensen
Rothari<br>3d
Liked by Sebastian Jensen
So basically, a single miligram of it? I am skeptical but also hopeful here. It might be good, taken rarely (once or twice a month maximally, avoiding tolerance development) for either 1) initiating the study or practice of something unfamiliar or 2) having to combine multiple methods to set up an environment/ecosystem that makes things possible 3)pushing through something especially difficult individually or 4)bundling cognitive tasks together<br>I'm not understanding the conclusion that few people get addicted from the gum itself. from the conclusion it seems like 2/5 very much DID get addicted from the gum itself?<br>https://pmc.ncbi.nlm.nih.gov/articles/PMC1939993/<br>Five never smokers used the nicotine gum daily. They had been using the nicotine gum for longer than the 429 ever smokers (median = 6 years vs 0.8 years, p = 0.004), and they had higher NDSS-gum Tolerance scores (median = 0.73 vs = -1.0, p = 0.03), a...