Light is vital to health.

Just as we depend on the right balance of nutrients from the food we eat, our body’s rhythm relies on the right light exposure at the right time of day. We call this your light diet.

Our biological clock, like most life on Earth, is linked to the to the Earth's 24-hour rotation through the light-dark cycle. Before urbanisation and industrialisation, people woke around sunrise and slept shortly after dusk. But the advent of electrical lighting has changed our environment and how we live within it.

We now spend an average of 90% of our day indoors, away from natural light. 

 Indoor lighting standards have been designed to meet a minimum threshold for visual acuity, but does not address the biological requirements. Our evenings too have changed with increasing amounts of artificial light present well after the sun has set. Considering our circadian rhythm relies on light to calibrate itself, disrupting our relationship with light has far-reaching consequences on our biology.

The Circadian Rhythm and Light

Beyond visual light.
Until recently, the role light plays in calibrating our circadian rhythm was not well understood. This began to change with the discovery of a third photoreceptor in our eyes, known as intrinsically photosensitive retinal ganglion cells (ipRGC’s). ipRGC’s contain a photopigment called melanopsin and unlike rods and cones they don’t contribute to vision. Instead, when exposed to the specific spectrum and intensity of daylight the ipRGCs send a signal to our master clock known as the suprachiasmatic nucleus (SCN). 

The Circadian Rhythm

The Circadian Rhythm and Light

Beyond visual light.
The SCN regulates the circadian rhythm by timing the release of hormones and neurotransmitters. One of the most identifiable hormonal cycles linked to light is the rise and fall of melatonin. As the sun sets melatonin is secreted preparing the body for sleep. The onset of melatonin is extremely important for timing and quality of sleep and even a short duration of bright light in the evening can delay the onset by up to 1 hour. As sunrise approaches we see a decline in the levels of melatonin and a sharp rise in the levels of cortisol (known as the cortisol awakening response). When these two cycles are aligned with each other and the 24-hour day they function like nature’s alarm clock (Fries et al., 2009).

Current lighting lacks the light our bodies need.

This has consequences for our health and wellbeing.

Of the body's function mediated by the circadian rhythm.


Working people suffering circadian disruption.

OSIN: Healthier Living with Light.

OSIN is on a mission empower people to improve their light diet by providing Nutritional Light™ tools—light that is inspired by nature to addresses the shortcomings of a modern lifestyle. Because we believe everyone should have access to Nutritional Light.