Melatonin is one of the most fascinating molecules in biology. Many people know it as the “sleep hormone,” produced by the pineal gland in response to darkness. Yet melatonin exists far beyond the human brain. Plants, animals, and even microorganisms make melatonin, using it to combat stress and maintain balance.
What makes melatonin so unique is that, whether in plants or humans, it protects cells at their most vulnerable points, where energy is generated and oxidative stress is highest. Even more exciting for longevity science, melatonin has been shown to stimulate the production of healthier exosomes, the cell-to-cell communication packages that drive regeneration and repair.
Plant vs. Human Melatonin: How It’s Made
In humans, melatonin is synthesized from the amino acid tryptophan. Specialized enzymes convert tryptophan into serotonin, which is then converted into melatonin. Production follows a circadian rhythm, peaking at night to regulate sleep, immunity, cellular repair, and recovery. This central release occurs primarily from the pineal gland, distributing melatonin into the bloodstream. Think of melatonin as having opposing effects to the stress hormone, cortisol.
In plants, the story looks different. Melatonin is made in multiple organelles, especially chloroplasts and mitochondria, the same sites where photosynthesis and respiration generate high levels of free radicals. Plants evolved melatonin as a frontline antioxidant defense. Because it is amphiphilic (both water and fat-soluble), plant melatonin freely crosses membranes, spreading through roots, leaves, fruits, and seeds.
The result? Melatonin is far more abundant in plants than in animals. Seeds, skins, and leaves can contain surprisingly high levels, which is why foods like rice, tomatoes, grapes, coffee, and red wine naturally deliver measurable amounts of melatonin.
What it Does
Across both plants and humans, melatonin serves as a master antioxidant and protector of cellular health.
- Antioxidant defense: Melatonin neutralizes up to 10 different free radicals in a cascade, making it more potent than many well-known antioxidants like vitamins C or E.
- Anti-inflammatory effects: It regulates cytokines and signaling pathways that keep inflammation in check.
- Cell cycle and DNA protection: In plants, melatonin plays a crucial role in regulating growth, photosynthesis, and resilience against drought or pathogens. In humans, it supports mitochondrial health, immune response, and even neuroprotection.
Because melatonin is both endogenous (produced within the body) and exogenous (consumed through diet or supplements), it bridges the natural and therapeutic worlds.
Melatonin and Exosomes: Internal Regeneration
The most cutting-edge discovery about melatonin is its influence on exosome biology.
Exosomes are tiny vesicles released by cells, carrying proteins, RNA, and other molecules to communicate with and influence neighboring or distant cells. Exosomes play a vital role in tissue repair, how the immune system communicates, and how aging progresses at the cellular level.
Studies show that when cells are pretreated with melatonin, the exosomes they release, known as MT-exosomes, carry enhanced properties:
- Stronger antioxidant and anti-inflammatory activity
- Greater regenerative signaling
- Improved ability to promote wound healing, kidney repair, and even neurological protection
In other words, melatonin doesn’t just act directly as a molecule; it stimulates your body to create better exosomes, which amplify your own internal repair system.
Endogenous vs. Exogenous
- Endogenous melatonin is made inside your body, with production declining as you age, beginning as early as the end of puberty. This drop is one reason older adults may struggle with sleep, immunity, and cellular repair.
- Exogenous melatonin comes from outside sources, either synthetic supplements or natural plant-based sources. Exogenous melatonin not only supports sleep but has been shown to trigger the same protective cascades as endogenous melatonin, helping to reinforce the body’s declining stores.
This raises two of the most common questions:
How much melatonin should I take?
There is no one-size-fits-all dose. Studies for sleep typically range from 0.5–5 mg. Some take doses up to 15 mg nightly. Higher levels are used in research settings for other therapeutic effects; however, starting with the lowest effective dose is safest. Tablets that dissolve under your tongue provide the best bioavailability. Always consult a healthcare professional before taking any supplements.
Where does exogenous melatonin come from?
It can be synthesized in labs or extracted from plants. Natural sources include nuts, seeds, fruits, and fermented products like wine or beer.
Longevity Science
At ReCELLebrate, we are deeply interested in how biomolecules like melatonin can support healthy longevity. Plant-derived exosome supplements, such as LONGEVEX, provide one route to nourish cellular communication and health with significant advantages over non-exosomal supplements. Melatonin complements this by stimulating your own cells to release healthier, more protective exosomes internally.
Together, they highlight a simple but powerful principle: when we align with nature’s conserved molecules, whether from our pineal gland or a grape seed, we give our cells the best chance to repair, regenerate, and thrive.
References
- Zhou Z, et al. Melatonin pretreatment on exosomes: Heterogeneity, therapeutic effects, and usage. Front Immunol. 2022;13:933736.
- Kołodziejczyk I, Kaźmierczak A. Melatonin—This is important to know. Sci Total Environ. 2024;919:170871.
- Arnao MB, Hernández-Ruiz J. Melatonin and Phytomelatonin: Chemistry, biosynthesis, metabolism, distribution and bioactivity in plants and animals—An overview. Molecules. 2019.