From 5-HTP to melatonin: how your body builds its own night signal
Every evening, as the light fades, your brain begins manufacturing its own signal for night. The signal is melatonin, a hormone released by a pea-sized gland deep in the brain, and its rising level is one of the ways your body knows the day is ending. You do not buy this substance at the supermarket. You build it. And the assembly line behind it explains one of the more curious ingredients on sleep formula labels: 5-HTP.
The production chain runs in four steps. It starts with tryptophan, an amino acid you eat in protein foods like eggs, cheese and poultry. The body converts tryptophan into 5-HTP. It converts 5-HTP into serotonin, one of the brain's principal messenger chemicals. And as darkness falls, serotonin becomes the raw material for melatonin. One chain, food to night signal.
So why do supplements offer the middle link rather than the start of the chain? Because of a bottleneck. Tryptophan has to compete with several other amino acids for the same transporter that carries them into the brain, which means a protein-rich meal can leave it queuing at the door. 5-HTP does not join that queue, and it sits one step closer to the finished product. Supplying the middle of the chain simply skips the crowd at the entrance.
The 5-HTP in supplements is not synthesised in a vat, as people often assume. It is extracted from the seeds of Griffonia simplicifolia, a woody shrub from West Africa whose seeds are unusually rich in it, one of those botanical oddities the supplement world quietly depends on.
There is a supporting actor in this story: vitamin B6. The enzyme that converts 5-HTP onward needs B6 as a helper to do its work, which is why thoughtful night formulas pair the two. Koru Sleep, the natural sleep support formula from Koru Nutrition in Christchurch, includes both among its seven compounds, the ingredient and the tool that puts it to work.
And one piece of free advice worth more than any capsule: the whole chain answers to light. Bright screens late in the evening tell the gland that built your melatonin to hold it back. Dim the lights as the evening goes on and the assembly line you were born with does more of the job on its own, which is, after all, how it ran for a few hundred thousand years before the light bulb.