Edit: I am not as confident anymore as I have been in Andrew Huberman's general epistemics, so take this post with a grain of salt. 

Introduction

In this post, I list all the advice from Andrew Huberman's podcast Sleep Toolkit: Tools for Optimizing Sleep & sleep and Sleep-Wake Timing. A large subset of that advice can also be found on his website, so feel free to read there and ignore this post. 

I did not do any research to check whether the advice is actually correct and comprehensive. If you know of any important missing tools or wrong advice in the list below, please let me know. I think the main tools for improving sleep that are missing from this podcast episode are:

• General CBT-I (Cognitive Behavioral Therapy for Insomnia);
• General stress reduction;
• Any other psychological improvement strategies (e.g., therapy against depression and anxiety);
• Choice of clothes, pillow, mattress, and blanket for sleeping;
• bedtime routines;
• Nutrition (except for some short advice on breakfast);
• Prescription Drugs.

If you know of other important factors, please let me know in the comments. 

In summary, the advice is centered around using 8 "tools" in such a way as to obtain a stable, healthy circadian rhythm:

• Light
• Darkness
• Temperature
• Food
• Exercise
• Caffeine
• Supplements
• Digital Tools

Below, I mostly focus on the advice and less on the reasoning behind that advice. My impression is that you can probably ignore much of the advice if you feel like your sleep is already great, though especially light exposure in the morning and dim light in the evenings seem like clearly useful for almost everyone. 

The Three "Critical Periods"

Huberman names three "critical periods": the morning, throughout the day, and the evening. He emphasizes the importance of one's behavior in the morning the most, as he claims it has a crucial effect on the circadian rhythm. 

Period 1: Morning (until ~3 hours after waking)

Early in the morning, Huberman recommends getting natural light exposure for setting the circadian rhythm, and to exercise, getting a short cold shower, and having breakfast for activating the body and increasing the core body temperature. While all of this "wakes up the body", Huberman indicates that it is also useful for getting better sleep later on.

Finally, Huberman lists some advice on how to responsibly use caffeine. I am not sure if he claims that caffeine can help with sleep (e.g., since it increases the core body temperature and thus might help for setting the circadian rhythm) or if his advice is mainly meant to reduce the damage to sleep caused by caffeine. 

Light Exposure

• Timing: immediately after waking or at least within the first 60 minutes
• Look into the general direction of the sun at a low solar angle
  • Don't look at it, especially if it's painful.
  • Don't wear sunglasses.
  • Eyeglasses or contact lenses are good, but windows are not.
    • UV protection is okay
• Duration:
  • Clear day: ~5 minutes
  • Cloud cover: ~10 minutes
  • Very overcast/rainy: ~20-30 minutes
• If this is not possible: use sunlight simulators/daylight simulators.
  • Cheap replacement:
    •  ring lights (they are often used for selfies)
    • Drawing LED Tablet
• If you wake up before the sun rises and want this to be your regular wake-up time, turn on bright artificial lights. 
• Do this at least 80% of the days in your life
  • Do it for an extended duration (twice as much) after missed days

Exercise

• Ideally: immediately after waking up.
  • Can be combined with sunlight viewing. 
• Examples of morning exercise:
  • Take a walk, light jog, skip ropes
• It doesn't have to be the most intense workout

Cold Shower

• Take a cold shower for 1-3 minutes
  • It increases the body temperature when the exposure is short
• Alternative: Cold tub/ice bath

Breakfast

• This also helps for increasing the body temperature
• After a big meal, you will be sleepy; thus, don't eat a huge breakfast

Caffeine

• Take into account that the personal effective dosage varies a lot.
• Delay the caffeine intake for 90 to 120 minutes after waking to reduce the afternoon crash (a dip may still happen)
  • This helps for avoiding drinking caffeine in the afternoon
• Limit the last caffeine intake to 2 pm - 4 pm or ideally even earlier
• Caffeine can disrupt sleep quality even if it seems like you're sleeping fine

Period 2: Late morning to Late afternoon (until ~5 pm)

Do's:

• Bright artificial lights from above
• Sunlight is good
  • Late in the afternoon, this is especially useful
    • Sunset light slightly counteracts the bad effects of artificial lights, even afterward

Further Comments:

• Limit or entirely avoid caffeine
• Napping is fine
  • Don't nap too late in the day.
  • You don't have to nap; if you don't feel like you profit from it, don't do it.
  • Don't nap longer than 90 minutes
• Napping alternatives:
  • NSDR (Non-sleep deep rest)
  • Yoga Nidra
  • Reveri App
• Exercise will delay the circadian clock, especially later in the day.
  • This doesn't mean you have to avoid it, but it is worth taking into account for some people. 

Period 3: Evening (from 6 or 7 pm until bedtime)

Light:

• Place lights low, e.g. on the floor
  • Have as little light as required to do what you want to do.
• Avoid bright artificial lights of any color
  • You may put on sunglasses when in a bright light environment (e.g. supermarket)
• Also dim screens
• Candlelight or moonlight have a low light intensity
• Blue blockers can help some people

Temperature (the opposite advice from the morning)

• Take a hot bath/sauna/shower, for a short time (not longer than 20-30 minutes)
  • This leads to a compensatory dip in temperature
• Avoid (especially heavy) exercise
• Make the sleeping environment cool
  • ~3 degrees less than during the day
  • Layer blankets as needed.
    • If it turns out too warm under the blankets, the body will automatically put feet/hands out of the blanket, so layering blankets gives more flexibility in temperature regulation than having a warmer room
• Put out socks unless you tend to wake up from cold feet.

Alcohol/CBD/THC

• Alcohol greatly disrupts sleep
• THC/CBD
  • The anxiety-reducing effect can help with falling asleep.
  • He does mention that THC disrupts the quality of sleep.
  • It seems like Huberman's assessment of these substances is mixed and he does slightly advise against using them, especially before trying other supplements (see below).

Further Advice

Supplementation

Main Supplement Stack

Use up to all three or none of the following. There is a wide margin for safety. Use them 30-60 minutes before bedtime. Warning: Huberman has a contract with a company selling these supplements and thus a conflict of interest. 

• Magnesium threonate: ~145mg
  • For ~5% of people: this disrupts the gut. If so, don't take it.
• Apigenin: 50 mg 
  • I heard somewhere else that this can have an effect on estrogen, so use it with caution.
• Theanine: 100-400 mg
  • This may make dreams more vivid in an uncomfortable way. If so, leave it out. 

GABA, Glycine, Myo-Inositol

Huberman also uses the following supplements in addition to the others. If the others don't work for you, you could also replace those with the options here. 

• Every 3rd or 4th night: 
  • 2 grams Glycine
  • 100mg GABA
• Myo-Inositol: every other night, 900mg
  • Not on nights when also using Glycine and GABA
  • Makes it easier to fall back asleep after waking up
  • Can reduce anxiety

A note on melatonin:

• Huberman claims it's less preferable than the others
• if you use it, use it in a 300-microgram dosage
• His opinion is to not use it
  • He mentions that melatonin can be hard to find in the right dosage and that the dosage is often not correctly stated. I am not sure if he would still generally recommend against using melatonin in cases when the dosage is correct.
  • He also mentions that melatonin can delay the onset of puberty. 
  • For a different take on melatonin, read Scott's article. 

Digital Tools

The following tools were mentioned above as tools for replacing naps. They can also be used for falling (back) asleep. He especially recommends the hypnosis in the reveri app. 

• Non Sleep Deep Rest (NSDR)
• Yoga Nidra is also zero cost. Many protocols exist
• Reveri App

Eye Masks, Earplugs, Bed Angle

Eye masks

• They can help.
• If the room is too warm, then the eye mask will increase the face temperature too much, which can lead to waking up.

Earplugs

• Some find them beneficial.
• The sound of the beating of one's own heart can be non-beneficial for some people.

Bed Angle

• Elevate the end of the bed by 3-5 degrees
• Do the opposite if you have problems with acid reflux.

Sleep Apnea

Sleep apnea is very bad. I don't remember much of what Huberman recommends, but the main recommendation seems to be to learn techniques for breathing through one's nose instead of mouth. 

Weekends

Keep sleep time relatively consistent on the weekend. 

• Don't sleep in more than one hour past your normal wake-up time 
• Use naps if you did not sleep enough. 
• Caffeine disrupts compensatory sleep more than normal sleep. Huberman especially advises against using it in the first 90 minutes of groggy days.

Jetlag/Shiftwork

Two hours before waking up, people have their daily temperature minimum. Huberman claims that being very active shortly before this minimum can delay it and thus delay the whole circadian rhythm, and the opposite is the case when being very active shortly after the minimum. For more details on this topic, see his podcast which specifically focuses on shift work and jetlag.