Could isolated blue light, especially at night, raise blood sugar and insulin independent of food?

The answer is a resounding yes

Exposure to isolated blue light can acutely affect glucose metabolism and insulin sensitivity, even in the absence of food intake

This is one of those points that reshapes your understanding of circadian biology, most notably the relationship between light and metabolic function

It points to both the power of full spectrum sunlight in its ability to reduce blood sugar (PMID: 38378043) and isolated blue light in its ability to destroy glucose metabolism (PMID: 27191727)

In this controlled study involving healthy adults, exposure to blue-enriched light (~ 468 nm) for three hours in the morning or evening led to increased insulin resistance compared to dim light conditions

Most importantly, evening exposure resulted in HIGHER peak glucose levels, indicating a diminished ability of insulin to regulate blood sugar effectively during that time

Animal studies show similar results (PMID: 31646762), but I’m solely interested in human beings

The implications of these on human beings is significant, to say the least

•••

Circadian Disruption Alters Glucose Control

Blue light stimulates melanopsin-containing ipRGCs in the eye, which influence the suprachiasmatic nucleus (SCN)

This, in turn, regulates:

• Insulin sensitivity in tissues
• Pancreatic beta cell function
• Hepatic glucose output

The implication is that isolated blue light disrupts this unfathomably complex system, causing insulin resistance and glucose spikes even without eating

•••

Isolated Blue Before Meals Could Worsen Postprandial Glucose

If isolated blue light already elevates glucose and suppresses insulin sensitivity before a meal, consuming carbohydrates soon after can cause:

• Higher blood glucose peaks

• Greater oxidative stress

• Increased long term risk for insulin resistance, diabetes, and obesity

The implication is that light environment is just as important as diet quality and timing in metabolic health (this is clear when you study the literature)

•••

Increased Risk for Metabolic Syndrome in Artificially Lit Environments

No surprise that elevated nighttime glucose, poor sleep quality through circulatory melatonin suppression, and circadian disruption skyrockets chronic disease risk

Think about your office, school, indoor gym, grocery store, the list goes on

•••

Diagnostic & Therapeutic Insight

This opens the door to use circadian principles and proper light exposure as a non-invasive intervention for type 2 diabetics, prevention of pre-diabetes, enhancing insulin sensitivity, and chronotherapy

•••

When blue light is received in isolation and outside of the circadian context, especially after nightfall, it destroys SCN signaling which impairs:

1. Normal glucose tolerance rhythms

2. Melatonin secretion, which has a regulatory role in insulin signaling

3. Coordination between central and peripheral clocks (pancreas, liver, muscle, adipose)

•••

The POMC system comes into play too

POMC neurons within the hypothalamus of the brain are key in energy and glucose regulation

POMC makes a-MSH in response to UV within the sun’s full spectrum, which activates MC4R (melanocortin-4 receptor).. regulating satiety, sympathetic tone, insulin sensitivity, and gluconeogenesis

Mistimed light exposure alters SCN signaling to the hypothalamus

This blunts POMC activation or desynchronizes it from feeding rhythms

Downstream effects include altered MC4R signaling, disrupted glucose utilization + insulin sensitivity

Increased sympathetic tone → cortisol elevation → worsened glucose regulation

Continued below
Hormonal and neuroendocrine mediators play a key role here as well

Isolated blue suppresses SCN-driven melatonin, disrupting nighttime insulin timing, increasing peripheral insulin resistance, and flattening leptin rhythms.. all undermining metabolic stability

The skin is a circadian organ

This fact throws the conventional narrative that unfiltered full spectrum sunlight inherently causes skin damage or cancer out the window

Here’s the proof: The skin is a highly dynamic circadian organ, with its layers (epidermis, dermis, and hypodermis) each possessing peripheral clocks that interact with the body’s central clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus

Skin, eyes, and brain are made of the same tissue when you’re an embryo (neuroectoderm)

Here’s the circadian truth about the infamous truck driver case - the one centralized dermatologists love to weaponize against sunlight exposure: This is the most misunderstood image in the health space when it comes to photoaging and skin cancer

It’s a case study that’s been twisted out of ignorance to fuel misinformation about sunlight

Circadian biology is the master regulator of all anti-cancer processes in the body

Through this, we understand that the demonization of sunlight, along with the lack of discussion about artificial light at night and circadian disruption, creates rising cancer rates

Here’s all the evidence you need Virtually all major anti-cancer processes are either directly or indirectly controlled by circadian biology

Some processes might seem less dependent on circadian rhythms at first glance

But it inevitably comes full circle

Why full-spectrum sunlight and circadian alignment are the ultimate probiotics and gut healers

I’m using first principles circadian biology and gut physiology to show you the power of this work

Gut health transcends what you eat We begin with the basics

The gastrointestinal system operates as a CIRCADIAN organ, which means it’s married to the light and dark cycle

Circadian biology regulates all aspects of gut physiology from motility to digestion to absorption to electrolyte balance

This is the bedrock of gut health

The Sun Paradox

Exposing the glaring contradictions of centralized dermatology, so you don’t fall fall prey to their iatrogenic interventions Centralized dermatology oversimplifies the sun-cancer connection while ignoring other major factors like isolated blue light, circadian disruption of the skin, the difference between isolated UV versus UV in the full spectrum, Vitamin D deficiency, and more

They push fear-based avoidance, which often leads to worse long-term health outcomes

Does the sun really cause skin cancer?

I’ll tell you why the studies are lying Research linking UV light to skin cancer is flawed due to poor study design, relying on isolated UV in nocturnal animals or cell cultures instead of full-spectrum sunlight on humans

This one idea changes your epistemological foundation regarding this subject

Why cloudy days are still worth stepping out for — and how the sun’s full spectrum is available through cloud cover: “Why should I go outside during winter or when it’s cloudy, there’s no sunlight!”

I’ve received this comment often

Let’s set the record straight on this subject and answer the question, once and for all

Even though you naturally want to stay wrapped up in a blanket during overcast days, the sun's full light spectrum continues to play a vital role in your health, regardless of the weather

Why full spectrum sunlight makes the skin more youthful — and how isolated blue and UV is toxic to the skin barrier: Let’s begin from first principles

If you’re religious or believe in evolutionary biology and adaptation, you can agree to this:

The skin barrier was made or evolved under the influence of full spectrum sunlight

There’s substantial evidence for this

Some things I’ve learned from reading The Nourishing Traditions Book of Baby & Child Care as a father

Here are some gems for you: Nutrition & Physical Degeneration by Weston A. Price is a must read for parents

Price was a dentist and nutrition researcher who studied traditional societies and found that nutrient-dense, whole foods led to excellent health and resistance to disease

His work highlighted the negative effects of processed diets and emphasized the importance of fat-soluble vitamins, raw dairy, organ meats, and fermented foods for optimal health

13 incredible facts about circadian biology 1. Every cell has a clock

Virtually every cell in your body in your body contains its own circadian clock, regulated by clock genes, which synchronize with your central clock in the brain (the SCN)

How getting UV-A shortly after sunrise will transform your mental health, protect you from sunburns, and deepen the quality of your sleep

Share this with a friend in need The circadian types love to speak about the importance of watching sunrise, but we need to go deeper

This thread is all about UV-A

UV-A light generally appears 15–30 minutes after sunrise, depending on your geographic location, altitude, and atmospheric conditions

It becomes noticeable as the sun rises higher and the atmosphere scatters less of the ultraviolet radiation

You sound ignorant when you say a tan is exclusively a sign of skin damage, here’s why

It’s time to understand melanin

Share if you learned something new Let me remind you that melanin has been conserved for hundreds of millions of years

It’s one of the most ancient and widespread biopolymers, found in a diverse range of organisms, including bacteria, fungi, plants, and animals

Here’s my response to anyone who claims that full-spectrum sunlight, particularly UV light in that context, is harmful to the skin

Bookmark and share this thread The following pictures showcase the lost faces of history, highlighting the raw, regenerative power of full-spectrum sunlight on the skin barrier

These pictures were taken in the early 1900s through the work of Dr. Auguste Rollier

But first, some context

Your body requires the sun’s raw, unfiltered full-spectrum light for the prevention of chronic diseases

Here are the benefits of each light wavelength, to a depth you’ve never seen before Ultraviolet (UV) Light

UV-C (100-228 nm):

Biophoton emission responsible for cellular communication and systemic function. DNA/RNA, tryptophan, tyrosine, phenylalanine, all aromatic amino acids, phospholipids in cell membranes, water, all absorb light within this range

Found this German company called LICHTBLOCK that offers these, and I have never been more pissed that a company doesn’t offer international shipping

If you own a photobiomodulation/circadian company, you need to be making these immediately

Send me a DM if you are

I want everything to do with these


Found their IG. About to DM them. Will keep all of you updated

Our evolutionary and circadian history readily shows that the use of modern sunglasses is antithetical to the function and health of our ocular system

But, there are historical examples of indigenous innovation

Here are some: If you’d like to understand my position on sunglasses and why they’re problematic for human health from a circadian standpoint look, study the thread below

https://twitter.com/zaidkdahhaj/status/1725187110020489564

Conductive sweat glands?

The human body has them

Here’s yet another piece of strong evidence as to why grounding isn’t pseudoscience:
Yes, human sweat glands are conductive due to the electrolytes (sodium, potassium, chloride) in sweat

But you must understand the difference between eccrine and apocrine sweat glands

20 circadian principles that will improve your quality of life, no matter your age or circumstance 1. Watch sunrise every AM

If you don’t have a clear view of the sun and horizon, don’t worry

Merely being outside at this time is enough because the outdoor environment is bathed in the sun’s full spectrum at all times

What matters more for the prevention of cancer (especially melanoma and non-melanoma skin cancer)..

Circadian biology or food?

Here’s a thread for the people who are convinced that diet is a more powerful intervention

If this resonates, share the thread

I’m proud of it I’ll begin by saying that every pillar of health must be in order to PREVENT cancer

Light environment, nutrition, detoxification, exercise, all of it is a key part of the discussion

You should strive to have a well-rounded lifestyle

1. I’m not saying you can eat like shit and get away with it

2. I am speaking on prevention of cancer, not treatment when you have been diagnosed with a form of cancer

3. There are hundreds of different cancer types that act differently when they manifest. Brother @AbudBakri can correct me on anything I’ve missed or may have gotten wrong

I already know many of you are going to attack this thread based on those points, which is why I’ve addressed them directly

A comprehensive rebuttal to @bryan_johnson video on why he avoids the sun. Read all of it below I have already humbled @hubermanlab

Now, it’s time to humble Bryan who is the poster child of hyper-reductionist ideas as it relates to health

https://twitter.com/zaidkdahhaj/status/1825636040193060943