We know that there are distinct circadian rhythms in the concentration of endogenous cannabinoids and melatonin in the blood. The generators of circadian rhythms in the body are mainly in the hypothalamus, with the suprachiasmatic nucleus (SCN) in the mammalian hypothalamus thought to be the main neural site for the integration of circadian rhythms.

Although it remains unclear whether the circadian rhythms of endocannabinoids and melatonin in the human brain are identical to those in exactly the same as in the blood circulatory system, it is clear that there is also a distinct rhythm.

CBD is an exogenous phytocannabinoid, which is completely different from the endogenous cannabinoids in the human body and cannot be secreted by the body.

CBD is therefore taken in a completely different way to melatonin when it comes to its role in helping you sleep:

  • CBD is not secreted by the body's circadian rhythm, it is an auxiliary endogenous cannabinoid and serotonin, GABAergic, and even melatonin act indirectly, and its concentration does not have to vary because of circadian rhythms.
  • Melatonin is mainly secreted by the body at night (it has also been found to be secreted not only in the brain but also in other organs), so to improve sleep you should take melatonin at night, taking it during the day may disrupt the circadian rhythm.

Pineal Gland and Melatonin

The pineal gland responsible for the secretion of melatonin is in the epithalamus and melatonin is a hormone regulated by circadian rhythms and inhibited by light stimulation. Thanks to fluorescence techniques, melatonin and serotonin have been identified in the pineal gland, along with quantitative variability based on circadian cycles.

The identification of the pineal gland as a distinct organ is attributed to Galen of Pergamon (130-200 BC), who first described the organ as part of the brain and called it the konareion or Latin conarium because of its shape. He first described this organ as part of the brain, described it as a gland, and called it konareion or Latin conarium because of its shape. in ancient times, the pineal gland was described by Van Gehuchten as a mystical organ because it bridged the gap between material and spiritual life.

Andreas Vesalius Bruxellensis's (1515-1564) anatomical description was the basis for René Descartes's (1596-1650) conceptualisation of the pineal gland as the 'seat of the soul' or the organ of psychophysiological control. "or organ of psychophysiological control. Descartes was a fervent defender of the ancient Greek beliefs which suggested that human passions altered cognitive processes and emotions and were creators of madness. This belief was maintained until the Renaissance.

With the development of technology and the advent of the microscope, the pineal gland acquired the unofficial title of "third eye", mainly because of its histological similarity to the lateral eye of amniotic vertebrates. Today, the concept of the third eye is part of the optical neuroendocrine system, consisting of the retina, the central nervous system and the pineal gland.

Melatonin research began in 1958 when Aaron B. Lerner (1920-2007) isolated 100 micrograms of N-acetyl-5-methoxytriphenylamine from 250.000 processed bovine pineal gland, a substance known as melatonin, at Yale University. The findings of melatonin research have acknowledged most of the hypotheses put forward by Descartes. Although humans are not considered to be photoperiodic, this hormone highlights the seasonal characteristics that can lead to seasonal affective disorder and, in the short term, to "jet lag" disturbances caused by sudden changes in time zones.

The pineal gland is now defined as the optical neuroendocrine sensor that forms an integral part of the brain, providing information about circadian rhythms and thus further linking the external world to the internal biochemical and physiological needs and functions of the body.

Melatonin mechanism

The precursor of melatonin is tryptophan, which is hydroxylated to 5-hydroxytryptophan by hydroxylase in the pineal cells. 5-hydroxytryptophan is decarboxylated to serotonin by aromatic-L-amino acid decarboxylase. Serotonin is then converted to melatonin thanks to the enzyme methyltransferase-O-hydroxy-indolase (HIOMT).

The role of melatonin is:

Antigonadotropins have an atrophic effect on the sexual organs, an effect that is highly dependent on the seasonal rhythm of secretion and therefore has potentially paradoxical effects.

Down-regulation of thyroid activity, hypothermia, sleep induction.

Modulation of beta receptors in the heart and increase in mesenteric artery dilation volume by increasing norepinefrine levels.

Regulation of the rate of glucocorticoid and melatonin synthesis through immunomodulation using NFƘB transcription factors and binding to ƘB receptors.

Antioxidant and free radical scavenging through induction of the Nrf2-ARE signalling pathway.

Melatonin anti-tumour, thymic modulator and neuroprotective.The melatonin receptors are represented by MT1, MT2 and MT3 receptors as representatives.With ageing, the number of receptors begins to decrease and the incidence of neuropsychiatric disorders increases. These receptors are also present in the cerebral cortex, hippocampus, basal nucleus, mesencephalon and midbrain. MT receptors are also located at the level of the retina, as well as in the vascularisation of the retina, choroidal layer, sclera, cornea, crystals and ciliary body. Melatonin has been shown to have a regenerative effect on corneal lesions and intraocular pressure regulation.

Endogenous cannabinoids and melatonin, influencing each other.

It is now thought that the circadian rhythm of endogenous cannabinoid secretion is controlled by the SCN in the hypothalamus, whereas melatonin is controlled by the pineal gland in the superior thalamus, and that the circadian signals received by the pineal gland are also at least partly transmitted by the SCN through the connecting organ.

It has also been found that melatonin acts on the SCN and other brain organs in the hypothalamus, so that changes in the circadian concentration of this secretory product are the result of a cycle of enhancement, rather than just one producing the other.

CBD and Melatonin for sleep, how do I choose?

The effects of melatonin are clear and many people take it before bedtime, especially when adjusting to jet lag.However, if you take more than your body needs, you do not wake up easily, or you wake up for some time and still do not achieve wakefulness.

CBD, on the other hand, is completely different. CBD itself has both focusing and sleep-aiding effects, in fact because the sleep-aiding effect is not a direct result of CBD, but to a large extent because CBD promotes the action of circadian rhythm-related secretions. So CBD doesn't have to be taken just before bedtime, the CBD accumulated in the body can help you sleep better at night.

Many people find that the effects of taking CBD for sleep are usually best after 2-3 days of taking it, whereas with CBD capsules the effects are more pronounced and longer lasting (absorption through the gut is longer).

Currently there are also CBD + melatonin products for sleep, this is better to take before bedtime, especially if you need to sleep urgently, in addition to which the effects of CBD may be more obvious after 2-3 days of continuous use.