The 80/20 Circadian Course

Trusted by 200+ students

Sleep well. Think clearly. Let your body do the rest.

Your body already knows how to sleep deeply, burn fat, and stay sharp all day. It just needs the right inputs at the right time. This course shows you exactly what they are.

Complete implementation framework100+ lessons across 5 modulesHosted on NotionWorks on any device
Start my reset · $249

One-time purchase · Lifetime access · 30-day guarantee

What you getA clear order of operations for light, sleep, and meal timing.
Built for real lifeWorks for parents, travelers, shift workers, and messy schedules.
Fast to startStart with the Circadian Audit. See exactly what's off in 10 minutes.
Made to simplifyNo gadgets. No supplements. No overhaul.

There's a simpler way to do this.

You already care about your health. You already put in effort. The missing piece isn't more discipline or more information. It's knowing which inputs actually matter and in what order.

A small number of circadian inputs control most of how you feel.

Hear it from Zaid

What you get

People who fixed their rhythm

"I wish I would have had this 2 years ago."

My health is already improving applying the knowledge. Big early change is visual acuity. If I ever practice my integrative sports medicine again it will be a circadian centered practice.

— @SirPalmeroy
"My afternoon slump vanished and sleep got fixed."

One of the best courses to fix your circadian rhythm. Now I understand why he didn't give a big list of supplements in the course.

— @BhavanChand
"This is a life-long learning opportunity. GO FOR IT."

The course will be regularly updated with distilled insights that would take many of us years to research, study, understand and apply.

— @TheMenta1ist
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What's inside

100+ lessons across 5 modules. Regularly updated with new research. Lifetime access.

01

The Philosophical Principles of Circadian Biology

The worldview that makes everything else click. Where circadian science meets first principles and gives you a foundation that holds up against any health claim you encounter.

02

Circadian Biology, Light Environment, and Sleep

The largest module. Quantum biology, the solar spectrum, circadian hormones, mitochondria, melanin, melatonin, vitamin D from the sun, eyesight regeneration, skin science, heliotherapy, the full light environment from sunrise to night, and a complete sleep system built from morning to bedtime. This module alone is worth the price of the course.

03

Grounding and Electromagnetism

How your body conducts, how the earth charges you, and how to manage your electromagnetic environment. Practical grounding protocols and EMF guidance you can apply immediately.

04

Water and Hydration

The science of structured water, when and how much to drink, water quality, and the researchers whose work shaped this field. Simple hydration rules that align with your circadian rhythm.

05

Bonus Content

How to read and trust scientific research. Plus ongoing additions as new circadian science emerges.

Common questions

Is there a guarantee?

Yes. 30 days. Go through the course, apply what you learn, and if you don't feel a real difference, email me for a full refund.

What happens after I buy?

You get a link to your Notion workspace within 60 seconds of checkout. Open it, start reading, start applying. No waiting, no drip schedule, no hoops.

Do I need any special equipment?

No. Just sunlight, darkness, meal timing, and your environment.

How long do I have access?

Lifetime. One payment, every future update included.

I already know about circadian biology. Is this still useful?

Most people who say this have scattered knowledge but no clear framework. This gives you the order of operations so you stop researching and start doing.

What format is the course?

It's a structured implementation framework hosted on Notion. You can work through it at your own pace on any device.

What if I have a complicated schedule or can't get morning sunlight?

Module 5 is built specifically for this. The course gives you real-life adaptation strategies for shift workers, parents, travelers, and anyone who doesn't live in a perfect world.

One-time purchase.
Less than a month of supplements.

You’re not paying for more information. You’re paying for a simpler system and fewer wasted months.

Monthly supplement stack$80–200/mo
Functional medicine consult$300–500
Sleep coach (6 sessions)$600–1,200
Biohacking gadgets you stopped using$200–1,000
The 80/20 Circadian Course$249 once

People who start this course say the same thing: they wish they'd found it sooner.The inputs are simple. The results come fast. And you keep the framework for life.

One investment. Lifetime access.

$249

One-time · Lifetime access · No subscription

  • Complete roadmap you can start today
  • 100+ lessons on light, sleep, skin, grounding, water, and more
  • Real-life playbooks for imperfect schedules
  • All future updates included
Start my reset

Secure checkout · Instant delivery · Start today

30-day guarantee.Apply the framework. If you don't feel a real difference in your sleep or energy within 30 days, email me for a full refund.

Ready to start?

A clear circadian framework you can follow, revisit, and use for years. One purchase. Lifetime access.

Start my reset · $249

One-time purchase · Lifetime access · 30-day guarantee

Zaid K. Dahhaj

Meet Zaid

I run a circadian biology newsletter read by over 10,800 people on Substack, where I translate peer-reviewed research into first principles that actually change how people live. I've coached clients one-on-one and watched the same pattern repeat: people drowning in health information while missing the handful of inputs that actually matter.

I built this course to fix that. Not more content. Not another protocol. Just the right inputs, in the right order, explained once so you can stop researching and start living.

I built this because I watched good people put in real effort and not get the results they deserved. The information was out there, but nobody had organized it into a clear path.

This course is that path. The right inputs, in the right order. Simple enough to follow, powerful enough to change how you feel every day.

Much love, Zaid

Not ready to buy yet?

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The 80/20 Circadian Course$249 one-time · Lifetime access
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