Evidence supporting the use of: L-tryptophan
For the health condition: Insomnia

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Synopsis

Source of validity: Scientific
Rating (out of 5): 3

L-tryptophan is an amino acid that serves as a precursor to serotonin, a neurotransmitter involved in mood regulation and sleep-wake cycles. The scientific rationale for using L-tryptophan to support or treat insomnia is based on its role in increasing brain serotonin levels, which can then be converted into melatonin, a hormone that regulates sleep. Several clinical studies, particularly from the 1970s and 1980s, showed that L-tryptophan supplementation (usually 1-5 grams at bedtime) could decrease the time it takes to fall asleep and improve sleep quality in some individuals, especially those with mild insomnia or sleep disturbances. However, more recent meta-analyses and systematic reviews suggest that while there is some evidence for efficacy, the overall effect size is modest, and results are inconsistent across studies.

L-tryptophan use declined sharply after reports in the late 1980s of eosinophilia-myalgia syndrome (EMS) linked to contaminated supplements, though the risk from pure L-tryptophan appears low. Currently, L-tryptophan is available as a dietary supplement, and its use for insomnia remains supported by some evidence but is not as robust or consistent as prescription sleep aids or other interventions. Overall, while scientific evidence exists to justify its use for sleep support, it is moderate in quality and strength.

More about L-tryptophan
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Other ingredients used for Insomnia

5-Hydroxytryptophan (5-HTP)
Agarwood
Agastache
Agrimonia pilosa
Albizia
Alpha lactalbumin
alpha-terpineol
amber
amino acids
anamu
anemarrhena asphodeloides
Anemone
Angelica
anise
apigenin
Aralia
Arani
ashwagandha
aster root
atractylone
Baikal Skullcap
balsam
banyan
bayleaf
benegut perilla (proprietary)
betony
big quaking grass
black cumin
black seed
blackboard tree
blackthorn
Borassus aethiopum
borassus palm
brahmi
Bupleurum
cactus
calamus
calcium
Calea zacatechichi
California poppy
cannabidiol
cannabinol
Capitate Valerian
carry me seed
Carthamus
cassia bark
catnip
Centella asiatica
Centella triterpenes
chamomile
cherimoya
cherry
Chinese salvia root
Chinese silkvine
chrysanthemum
cinnamon
citron
Clary sage
Clerodendrum indicum
Clerodendrum trichotomum
Coptis chinensis
corktree
Corydalis
cowslip
Cyathula
Cymbopogon martini
David\'s milkberry
Doxylamine succinate
dragonhead
elephant\'s head
elk antler
Embelia
Erodium cicutarium
European Elder
fennel
Ficus religiosa
Ficus simplicissima
Flueggea suffruticosa
frankincense
fringed pink
GABA (gamma aminobutyric acid)
ganoderma
Gardenia jasminoides
Gelsemium
geraniol
giant blazingstar
Glycine
goji berry
gooseberry
gotu kola
Greek mountain tea
heartwood
Homalomena
honeybush
hops
Indian frankincense
jasmine
Jatamansi
Jatoba
jujube
jujubosides
kava
kavalactones
kiwi
kudzu
Kukicha
L-tryptophan
labrador tea
lactium casein decapeptide
Lactucarium
Lady of the Night
Large-leaved linden
lavender
lemon balm
Lesser speargrass
Lilium polyphyllum
lily
linalool
linden
Lindera
lingzhi
little ironweed
longan
loquat
Loranthus
lotus
lotus seed
lupulinum
Lycium
maca
Macaranga indica
mace
magnesium
magnolia
magnolol
mallow
Marine lipid
Marjoram
Matapalo Tree
Melatonin
Mesua
Microtea debilis
Milk Protein
Mimosa
Moringa
Morning glory
Morus
Motherwort
Mulungu
Myrcene
Nardostachys
Night jessamine
Nymphaea caerulea
Nymphaea nouchali
Onosma bracteatum
Ophiopogon
ophiopogon root
orange
orchid
Oroxylum indicum
Osmanthus
Osthole
paeoniflorin
passionflower
Passionfruit
Patchouli oil
peach
perilla
Persimmon
phlorotannins
phytocannabinoids
Pimpinella
pollen
Polygala
polygala root
Polygonatum
Polygonum
polysaccharides
poppy
Portulaca
Premna
Pulsatilla
purslane
quail egg
Rauvolfia
reishi mushroom
rice
Rooibos
rose
rose oil
Rubiaceae
rue
saffron
Safranal
sage
Salvia
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Sarivan
Schisandrins
Scoparia dulcis
scrophularia root
Sedanenolide
Self-Heal
Semecarpus anacardium
Sensitive Plant
Shankhpushpi
silk tree
skullcap
soursop
Southernwood
Speedwell
Spikenard
Stachytarpheta cayennensis
Sumac
Sumbul
Sweet Annie
Sweet Bay
Sweet Orange alcohol
Sweet Woodruff
Sword Bean
Szechuan lovage
Tagara
Terminalia
Tetrahydropalmatine
Valerenic acid
Valerian root
Verbena
Vervain
Vetiver
vitamin B6
Walnut
Waterhyssop
Wax Gourd
Winter Begonia
Winter Savory
Withanolides
Wood betony
Yellow-Fruit Nightshade
Ylang ylang
Yuzu
Zinc

Products containing L-tryptophan

Designs For Health Amino Acid Supreme™
Thorne Amino Complex Berry
Thorne Amino Complex Lemon
Pure Encapsulations Amino-NR
Pure Encapsulations Amino Replete
Metagenics BioPure Protein® Powder
Pure Encapsulations Cognitive Aminos
Pure Encapsulations Essential Aminos
Klean Athlete Klean Essential Aminos + HMB®
Klean Athlete Klean Isolate ™
Pure Encapsulations L-Tryptophan
Pure Encapsulations L-Tryptophan
Douglas Laboratories L-Tryptophan
Douglas Laboratories Muscle Protect™ with HMB®
Metagenics Perfect Protein® Pea & Rice Chocolate Powder
Metagenics Perfect Protein Pea & Rice Vanilla Powder
Metagenics Perfect Protein Whey Chocolate
Metagenics Perfect Protein Whey Vanilla
Thorne RecoveryPro NSF
Metagenics Ultra Glucose Control® Chocolate
Metagenics Ultra Glucose Control Chocolate
Metagenics Ultra Glucose Control Vanilla
Metagenics Ultra Glucose Control Vanilla
Metagenics UltraGI Replenish® Chocolate
Metagenics UltraGI Replenish Chocolate
Metagenics UltraGI Replenish Vanilla
Metagenics UltraGI Replenish Vanilla
Metagenics UltraInflamX Plus 360°® Chocolate/Orange
Metagenics UltraInflamX Plus 360° Mango
Metagenics UltraInflamX Plus 360° Mango
Metagenics UltraInflamX Plus 360° Orange
Metagenics UltraInflamX Plus 360° Original Spice
Metagenics UltraInflamX Plus 360° Pineapple/Banana
Metagenics UltraInflamX Plus 360° Pineapple/Banana
Metagenics UltraMeal Advanced Protein® Dutch Chocolate
Metagenics UltraMeal Advanced Protein French Vanilla
Metagenics UltraMeal Advanced Protein Plain
Metagenics UltraMeal Cardio 360°® Pea/Rice Chocolate
Metagenics UltraMeal Cardio 360° Pea/Rice Vanilla