Epistemic status: very shallow google scholar dive. Intended mostly as trailheads for people to follow up on on their own.

previously: https://www.lesswrong.com/posts/h6kChrecznGD4ikqv/increasing-iq-is-trivial

I don't know to what degree this will wind up being a constraint. But given that many of the things that help in this domain have independent lines of evidence for benefit it seems worth collecting.


dark chocolate, beets, blueberries, fish, eggs. I've had good effects with strong hibiscus and mint tea (both vasodilators).


Regular cardio, stretching/yoga, going for daily walks.


Meditation, math, music, enjoyable hobbies with a learning component.

Light therapy

Unknown effect size, but increasingly cheap to test over the last few years. I was able to get Too Many lumens for under $50. Sun exposure has a larger effect size here, so exercising outside is helpful.

Cold exposure

this might mostly just be exercise for the circulation system, but cold showers might also have some unique effects.

Chewing on things

Increasing blood flow to the large masseter muscles seems to have a broadly stimulating effect on blood flow to the head in general. You can buy unflavored gum for cheap, or xylitol gum which has a positive side effect on decreasing cavity formation.

Things to avoid

vasoconstrictors, notably cigarettes, alcohol, stimulants. Caffeine seems to cause acute vasoconstriction followed by supranormal vasodilation? Not clear on the research here.


I consider the evidence on these a bit weak.

Bacopa is the only nootropic I've taken besides stimulants that has a seemingly noticeable effect (most notably on recall).

Vinpocetine has supposedly shown increased blood oxygenation in the brain.

Pyrroloquinoline Quinone (PQQ) has shown working memory effects with increased blood flow to the prefrontal cortex...in the elderly.

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Personal anecdote:

Ever since reading George's post, I've been noticing ways in which I have been (subconsciously) tensing muscles in my neck-- and possibly around my vagus nerve and inside my head. I wonder if by tensing these muscles, I'm reducing blood flow.  

(I can think of reasons why someone might learn to do this on purpose actually, eg in response to some social stress.)

So now I'm experimenting with relaxing those muscles whenever I notice myself tensing them. Maybe this increases blood flow, idk. It maybe feels a little like that.

Update: I resolved maybe all of my neck tension and vagus nerve tension. I don't know how to tell whether this increased by intelligence though. It's also not like I had headaches or anything obvious like that before

Similar situation in my life...there are times when I am attempting to fall asleep and I realize suddenly that I am clenching my teeth and that there is considerable tension in my face. Beginning from my closed eyes down to my mouth I relax my facial muscles and I find it becomes easy for me to fall asleep.

In waking life too there are instances where I recognize my facial and bodily tension but I notice these situations less often than when I am trying to sleep. Being conscious of tension in my body and then addressing that tension when it occurs has on occasion made me calmer.

I am uncertain regarding the utility of more expensive interventions and or intensive investigations for alleviating tension, and have not really looked into it (but want to, somewhat).

Note that vasodilators can reduce the blood flow to the brain because they potentially work on all blood vessels, not only those in the brain.

What things decrease blood flow to the brain?

Insulin insensitivity and weight gain Poor sleep Hypertension High cholesterol

Please provide more details on sources or how you measured the results.

Sources are a shallow dive of google and reading a few abstracts, this is intended as trailheads for people, not firm recommendations. If I wanted them to be reccs I would want to estimate effect sizes and estimates of the quality of the related research.

The subtext here seems to be that such references are required. I disagree that it should be.

It is frequently helpful but also often a pain to dig up, so there are tradeoffs at play. For this post, I think it was fine to omit references. I don't think the references would add much value for most readers and I suspect Romeo wouldn't have found it worthwhile to post if he had to dig up all of the references before being able to post.

The subtext is that I'd like to have them if the author has them available. It sounded like it's applied/used by the author. Also, it's a frontpage post and the LW standard on scholarship is typically higher than this. 

I'm fine with romeostevensit's reply that it's from a shallow google dive, but would have preferred this to be a QuickTake or at least an indication that it's shallow.

Hmm, good point this should probably have an epistemic status.

Increasing blood flow to the large masseter muscles seems to have a broadly stimulating effect on blood flow to the head in general. You can buy unflavored gum for cheap, or xylitol gum which has a positive side effect on decreasing cavity formation.

Never thought about this one, quite interesting 🙃