The 80/20 Circadian Course

Trusted by 180+ students

You're not broken. You're out of rhythm.

Fix the few circadian inputs your body actually runs on. Sleep, energy, metabolism, and clarity fall back into place.

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You've tried everything.
That's actually the problem.

You track your sleep. You take the supplements. You read the threads, buy the gadgets, follow the protocols.

And you still wake up tired. Still crash at 2pm. Still feel like your body is working against you instead of for you.

Here's what nobody tells you:

More information isn't the answer when the order of operations is wrong.

The frustrating truth: the fix is simpler than everything you've already tried. But nobody profits from telling you that.

A small set of circadian inputs drives the majority of your health outcomes. Fix those, and most problems stop needing to be managed.

This course shows you exactly which inputs, in what order. And what to stop wasting your time on.

What actually changes

When the right inputs are restored, downstream problems resolve themselves:

01

Sleep stops being a project

No more forcing it. Fix daytime inputs and your body remembers how to sleep on its own.

02

Energy becomes predictable

The afternoon crash. The morning fog. These are symptoms of misaligned timing, not character flaws.

03

Fat loss stops fighting you

When circadian timing is off, your metabolism stores instead of burns. Fix the input, change the result.

04

Mental clarity returns

Brain fog isn't a thinking problem. It's a timing problem. Aligned rhythms bring the sharpness back.

People who fixed their rhythm

Screenshots from real students and supporters. Unedited.

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Be honest with yourself

This isn't for you if
  • You want a magic supplement list
  • You're looking for another hack to collect
  • You won't change how you interact with light
  • You want complex, not clear
This is for you if
  • You're tired of trying everything and still feeling off
  • You want a framework, not another rabbit hole
  • You want to fix root causes, not manage symptoms
  • You're ready to do less, but do it right

What's inside

01

How the circadian system actually works

The foundation that makes all other health advice either click or reveal itself as noise.

02

The 80/20 light rules

The single biggest lever. Which light exposures matter, which don't, and how to use sunrise, midday, sunset, and darkness strategically. Without living like a monk.

03

Sleep. Fixed without forcing it

Why your sleep problem is almost certainly a daytime problem. No trackers, no supplements, no trying harder.

04

Metabolism & fat loss, circadian-first

Why calories fail when timing is wrong. How to make fat loss feel like alignment instead of punishment.

05

Built for real life

Simple rules that travel. How to recover from late nights, adapt to imperfect schedules, and stop obsessing.

Common questions

Do I need any special equipment?

No. The course is built around inputs you already have access to: sunlight, darkness, meal timing, and your environment. No gadgets required.

How long do I have access?

Lifetime. One payment, permanent access, including all future updates.

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

Most people who say this have a lot of scattered knowledge but no clear framework. This course organizes what matters into an order of operations so you can stop researching and start implementing.

Is this just about light?

Light is the primary lever, but the course also covers sleep architecture, meal timing, metabolism, fat loss, and how to adapt everything to real life. Light is the foundation. The rest builds on it.

What format is the course?

It's a structured 4-week 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.

A year from now, you'll either have fixed this or you'll still be managing it.

Same supplements. Same trackers. Same exhaustion dressed up as discipline.

Or: you learn which inputs actually matter, fix them once, and spend your energy on your life instead of your health.

Less than a month of supplements
you'd eventually stop taking

Most people spend more managing symptoms than it costs to fix what's actually wrong.

Priced lower for wider access

$249

One-time · Lifetime access · No subscription

  • Complete 4-week implementation framework
  • The 80/20 light protocol
  • Circadian sleep, metabolism & fat loss modules
  • Real-life adaptation strategies
  • All future updates included
Get Instant Access

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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
Zaid K. Dahhaj

Meet Zaid

I run one of the largest circadian biology newsletters on Substack, where I break down peer-reviewed research into first principles that people can actually use.

I built this course because the information exists, but nobody had organized it into a clear order of operations. Most people don't need more knowledge. They need the right inputs, in the right sequence, explained once and done.

That's what this course is.

I built this because I kept watching people apply massive effort for minimal return. Or quit entirely because the information load was crushing them. I've also experienced and witnessed how life-changing this work can be.

The problem is never motivation. It's knowing which levers actually matter.

If you take this seriously, it will permanently change how you think about health. And how little effort it actually requires.

Much love, Zaid