Compare every L-Tryptophan product across UK retailers on Suppio, ranked by true value - price per active dose, not pack size. Prices refreshed daily.
Essential amino acid and precursor to serotonin and melatonin
We rank L-Tryptophan by price per gram of active ingredient - not by pack size - so a bigger tub with a worse price per dose can't outrank a smaller one that's actually cheaper.
What it is
L-Tryptophan is an essential amino acid, which is a building block for proteins that the body cannot make on its own. Because it is essential, it must be obtained through food or supplements. It acts as a precursor, meaning it is the raw material the body uses to create other important chemicals.
Why it's used
It is primarily used to help the body produce two key substances:
Serotonin: A chemical messenger in the brain that helps regulate mood and feelings of well-being.
Melatonin: A hormone that controls the sleep-wake cycle and tells the body when it is time to sleep.
How it's made
To create the supplement, manufacturers typically extract the amino acid from protein sources through a process called fermentation. Microorganisms are used to produce the substance in large tanks, which is then purified and dried into a powder. This powder is then put into capsules or pressed into tablets for sale.
What it typically costs
This ingredient is generally mid-range in price. This is because the fermentation process required to isolate the amino acid is more complex than simple mineral extraction, but there is enough global supply and competition among manufacturers to prevent it from becoming a luxury-priced item.
Dosage by purpose
Purpose
Typical studied dose
Evidence
depression
3 grams per day, 6 to 8 grams per day, or 214 milligrams per kilogram of bodyweight per day
Suppio matches identical products across UK retailers by barcode, then ranks by price per active dose rather than sticker price. Value rankings only ever include listings Suppio has independently verified against the live retailer page - unverified data is shown on each product’s own page but excluded from ranking.
Prices across our retailer network are refreshed at least daily.
Essential amino acid and precursor to serotonin and melatonin
How does Suppio calculate the best-value L-Tryptophan?
We rank L-Tryptophan by price per gram of active ingredient - not by pack size - so a bigger tub with a worse price per dose can't outrank a smaller one that's actually cheaper.
Are these prices verified?
Suppio matches identical products across UK retailers by barcode, then ranks by price per active dose rather than sticker price. Value rankings only ever include listings Suppio has independently verified against the live retailer page - unverified data is shown on each product’s own page but excluded from ranking.
How often are L-Tryptophan prices updated?
Prices across our retailer network are refreshed at least daily.