Herbal Sleep Medicine.
Circadian Regulation: behaviours that are restorative and critical for us to function.
For some of us it is inevitable that whenever you read this., at some point over the next few hours you will carry out your daily routine of… sleeping.
Our very own multi-synaptic pathways, control secretion of melatonin through the suprachiasmatic nucleus (suffice to say), contributing the drive to sleep 1, 2.
In many ways we describe this, as how connected we are with the environment, rising with the sun on waking and aligning the approximate 24-hour[ish] circadian bio-rhythm, preparing to rest as the sun goes down in the evening.
Perhaps one of our obvious zeitgebers (e.g., in this case, the subtle clue that might indicate to us as to what time of the year that it is…) are the barren, leafless trees in our surroundings indicating Winter., or the flowers that are opening informing us that it is early Spring, or their preferred season to bloom. Further still, The Flower Clock, infamously drawn out by Linnaeus (1751) has long described the opening and closing of many flowers., even at particular times of the day 3.
Cestrum nocturna L, ‘Lady of the Night’ or the Night-blooming Jasmine., is one of the many phyto-wonders that have been frequently studied for their increased night-time scent, hypothesised to be regulated by endogenous circadian time-keeping, influenced by the light and temperature associated with different parts of the day. This increased presence, is thought to function as optimising the attraction for only the useful of potential pollinators 4, 5.
Our best aims to understand the functions of sleep, is that of as the restorative process, much as our physical body restores by quiet rest in waking-life, we assume that the sleep process may complete this same function for our brain, optimising its function-potential during wakefulness 6.
This understanding is then confirmed by a loss of behavioural responsiveness, and EEG studies of neuronal activity patterns 7.
The environmental-circadian connection for many of us., completes dependably and repetitively every day and every night. However, if this normal rhythmicity is disrupted., it is only then that its functions become apparent, as disease and dysfunction start to bring it to our attention.
Particularly, this may be the most relevant factor for shift-workers., who may experience the challenges of balancing the mind and physical to working its routines against the environmental influences. Essentially, this is disruption of the temporal alignment between what is known as Process S (homeostatic: build-up of pressure for sleep over prolonged wakefulness) and Process C (circadian: based on an approx. 24hr rhythm) and potentially leads to sleep-wake disorder 8.
Furthermore, in this view, the Process S is thought to be responsible for the slow-wave sleep that occurs in the first half of the night, whereas the Process C is thought to regulate the second half., so it is seen where the propensity of sleep may also now be altered, as a result of the disruption 8.
As holistic beings, we are continuously and constantly communicating…, through peripheral tissues-central nervous system, from each organ to other organs., and endocrine structures are producing those critical hormone substances, that equip us to deal with everyday functions, based on both these relationships with our environment and homeostatic processing.
This then becomes increasingly reflected in studies published on shift-work and the increased risks of associated hypertension, related cardiovascular disease, mood disorders, reproductive and other health conditions 9, 10, 11.
Levels of endocrine substances are produced in various levels throughout the day and night. Patterns such as the rise in Growth Hormone (GH) are thought to be associated with insulin resistance and protein synthesis 12. The pattern of cortisol production stimulated by ACTH, is shown to build-up through sleep., in preparation for the waking states, then peaking around 7-8am 13. Whilst these patterns seem to be appropriately controlled in order to meet our needs of business…, so too does the response of target tissues to those signals, that also vary accordingly.
Light signals entraining the suprachiasmatic nuclei (SCN), are also regulators of body temperature (falling to nadir core body temperature rhythm approx. 2hrs before entrained waking), that are then projecting to the preoptic area 14, 15.
Recent clinical studies have shown these cycles as important components in acting as cues for the efficient phase-entraining of the physiological functioning organs and individual oscillators in cultured cells and tissue explants, both directly or indirectly 16.
To this end., despite sleep-wake cycle being perhaps the most evident., almost each physiological and behavioural parameter, cycles the approximate 24-hr circadian rhythms.
There are also many other factors that will be dependent on our sleep-wake and the fast-feed behaviours, such as levels of insulin or adipokines [critical roles in body function, energy metabolism, and inflammation]. These patterns are largely governed by these feeding states, as well as light and dark cycles 17, 18, 19.
It is Photic History., that modulates both melatonin suppression and circadian phase shifts, meaning that depending on the time of day or night that we are exposed to light at the retina., it is well documented to be possible to either advance our circadian phases through light exposure during the morning., or delay it through exposure during the evening 20.
Practically, this informs us that routine that optimises natural light particularly first thing in the morning., can strengthen our circadian alignment and rhythm, and has been shown to improve sleep latency, sleep onset and sleep measurement 21.
Equipped with our recognition of our endocrine patterns then, we too can support and strengthen our behaviours to optimise our functioning., knowing how to make use of these time-of-day circadian oscillations.
Herbs., or phytomedicines., are excellent in helping to establish better support and regulation for the endocrine system through nourishing the adrenals, or for managing daytime energy levels.
Perhaps we might support the optimal gastrointestinal function and microbiome, possibly through nutrition, bitters or sours. And then of course [or perhaps then more traditionally in our understanding under the term of Herbal Sleep Medicine.,] we may aim to induce, rebalance and to promote the restorative sleep-schedule.
However., what is truly exciting about this commitment to a circadian-focused approach., is that the multidimensional nature of herbal medicine, to the prescriber, is not just about working with the many body-systems holistically, or even the vast pharmacy of plant medicines that can be applied. But it is also an approach that in some cases may not be designed as a ‘one-size-fits-all’ to dosing and medicating for simplicity and conventionalism of timings, for a targeted sleep prescription e.g., on waking in the morning, or before bed. Of course, at times [often] this prescription is totally justified.
However, we do not overlook the wider picture in the herbal prescription of the herbal stars-of-the-show themselves, in relation to their place in the absorption at certain times of day., at certain intervals between meals and metabolism for the individual, contributing to its circadian regulation and alignment as the whole., which in particularly where endocrine disruption has been identified., is a very desirable action in remodulating and rebuilding the systems., and well worth an additional consideration in a therapeutic Herbal Sleep Medicine.
References
1. Klein, D. C., Moore, R.Y. (1979) Pineal n-acetyltransferase and hydroxyindole-o-methyltransferase: Control by the retinohypothalamic tract and the suprachiasmatic nucleus. Brain research.
2. Czeisler, C. A., Kronauer R. E., Allan, J.S., & Duffy, J.F., Jewett, M.E., Brown, E.N.., Ronda, J. M (1989) Bright light induction of strong (type 0) resetting of the human circadian pacemaker. Science 244:1328-1333.
3. Linnaeus, C. (1751) Philosophia Botanica (pages 274-276), cited in: www. linnean.org/Linnaeus-floral-clock. Accessed: Feb 2023.
4. Fenske, M. & Imaizumi, T. (2016). Circadian Rhythms in Floral Scent Emission. Frontiers in Plant Science. 7. 10.3389/fpls.2016.00462.
5. Overland, L. (1960). Endogenous rhythm in opening and odor of flowers of Cestrum nocturnum. Am. J. Bot. 47, 378–382.
6. Carskadon, M. A., & Dement, W. C. (1979). Effects of Total Sleep Loss on Sleep Tendency. Perceptual and Motor Skills, 48(2), 495–506.
7. Carskadon, M.A., & Dement, W.C. (2011). Monitoring and staging human sleep. In M.H. Kryger, T. Roth, & W.C. Dement (Eds.), Principles and practice of sleep medicine, 5th edition, (pp 16-26). St. Louis: Elsevier Saunders.
8. Borbely, A. A. (1982) A two process model of sleep regulation. Hum Neurobiol 1:195-204.
9. NTP (National Toxicology Program) (2021) National Toxicology Program Cancer Hazard Assessment Report on Night Shift Work and Light at Night. Available at https://ntp.niehs.nih.gov
10. Maidstone, R.J., Turner, J., Vetter, C., Dashti, H. S., Saxena, R., et al. (2021) Night shift work is associated with an increased risk of asthma. Thorax.2021; 76:53–60.
11. Manohar, S., Thongprayoon, C, et al (2017). Associations of rotational shift work and night shift status with hypertension: a systematic review and meta‐analysis. J Hypertens.2017; 35:1929–1937.
12. Takahashi, Y. (2012) Essential roles of growth hormone (GH) and insulin-like growth factor-I (IGF-I) in the liver. Endocr. J. 59, 955–962 (2012).
13. Kalsbeek, A, van Heerikhuize, J. J., Wortel, J. & Buijs, R. M. (1996) A diurnal rhythm of stimulatory input to the hypothalamo–pituitary–adrenal system as revealed by timed intrahypothalamic administration of the vasopressin V1 antagonist. J. Neurosci. 16, 5555–5565 (1996).
14. Kräuchi, K. (2007) The thermophysiological cascade leading to sleep initiation in relation to phase of entrainment. Sleep Med Rev. 2007; 11:439–51.
15. Benloucif, S., Guico, M. J., Reid, K.J., Wolfe, L. F, (2005) Stability of melatonin and temperature as circadian phase markers and their relation to sleep times in humans. Journal of biological rhythms. 2005; 20:178–188
16. Saini, C., Morf, J., Stratmann, M., Gos, P., Schibler, U. (2012) Simulated body temperature rhythms reveal the phase-shifting behavior and plasticity of mammalian circadian oscillators. Genes Dev. 2012; 26:567–80.
17. Van Cauter, E, Copinschi, G (1999) Human growth hormone secretion: basic and clinical research. Totowa, NJ: Humana Press, Inc; 1999. Interactions between growth hormone secretion and sleep.
18. Van Cauter, E., Blackman, J.D, Roland, D., Spire, J.P., Refetoff, S., Polonsk, K.S. (1991) Modulation of glucose regulation and insulin secretion by circadian rhythmicity and sleep. J Clin Invest. 1991; 88:934–942.
19. Skene, D. J, Skornyakov, E., Chowdhury, N. R., Gajula, R.P., Middleton, B., Satterfield, B. C, Porter, K. I., Van Dongen, HPA, Gaddameedhi, S. (2018) Separation of circadian- and behaviour-driven metabolite rhythms in humans provides a window on peripheral oscillators and metabolism.
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21. Boubekri, M., Cheung, I.N., Reid, K.J., Wang, C.H., Zee, P.C. (2014) Impact of windows and daylight exposure on overall health and sleep quality of office workers: A case-control pilot study. J. Clin. Sleep Med. 2014; 10:603–611.
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Botanical Information: POWO (2023). Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; http://www.plantsoftheworldonline.org Retrieved 27 May 2023 and POWO (2026). “Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; https://powo.science.kew.org/.
Originally published: 27/06/2023
This article was recently reviewed by author for accuracy and updated on 6th October 2026, to include the latest information and taxonomy.
Whilst every care is taken to ensure accurate, reputable and the most recent sources and research for this information, this content is not intended as substitute for advice or treatment from a professional clinician. As with conventional medicines, herbal and natural medicines have active ingredients and can have potent effects and interactions with the body, medications, and with other conditions. Especially for those who are taking prescription or over-the-counter medications, it is advised to consult a professional herbalist or medical doctor before beginning any herbal, supplement or lifestyle program. Care and responsible administration is always strongly advocated.
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