Quick Comparison
| 5-HTP | Taurine | |
|---|---|---|
| Half-Life | 2-5 hours | 1-2 hours (plasma), but brain levels persist longer |
| Typical Dosage | Standard: 50-200 mg daily. For mood: 50-100 mg 2-3 times daily. For sleep: 100-300 mg 30-60 minutes before bed. Start low — some people are very sensitive. Take with food to reduce nausea. | Standard: 500-2000 mg daily. Anti-aging research (animal-equivalent): 1000-3000 mg daily. Can be taken at any time of day. |
| Administration | Oral (capsules, tablets). Take with food to reduce GI side effects. Evening dosing preferred for sleep benefits. | Oral (capsules, powder, present in energy drinks at subtherapeutic doses). |
| Research Papers | 10 papers | 10 papers |
| Categories |
Mechanism of Action
5-HTP
5-HTP readily crosses the blood-brain barrier via the large neutral amino acid transporter (LAT1/SLC7A5), unlike serotonin itself which cannot. Once in the brain, aromatic L-amino acid decarboxylase (AADC, also called DOPA decarboxylase) converts 5-HTP to serotonin (5-hydroxytryptamine) using pyridoxal-5-phosphate (active vitamin B6) as a cofactor. This completely bypasses tryptophan hydroxylase (TPH2), the rate-limiting enzyme in the normal serotonin synthesis pathway from dietary L-tryptophan. The result is a reliable, dose-dependent increase in serotonin across multiple brain regions including the dorsal raphe nucleus, hippocampus, and prefrontal cortex. Elevated serotonin activates 5-HT1A autoreceptors (calming), 5-HT2A/2C postsynaptic receptors (mood modulation), and 5-HT3 receptors (gut-brain signaling). In the pineal gland, serotonin is converted by arylalkylamine N-acetyltransferase (AANAT) to N-acetylserotonin, then by hydroxyindole O-methyltransferase (HIOMT) to melatonin — explaining the sleep-promoting effects.
Taurine
Taurine activates GABA-A receptors (particularly extrasynaptic δ-containing subtypes) and glycine receptors (GlyR) as a partial agonist, providing inhibitory modulation that reduces neural excitability and hyperexcitability. It acts as a powerful antioxidant, scavenging hypochlorous acid, hydroxyl radicals, and peroxynitrite in mitochondria and cytosol. Taurine regulates calcium homeostasis via modulation of ryanodine receptors and IP3 receptors, preventing excitotoxic calcium overload. It modulates osmotic balance through the taurine transporter (TauT/SLC6A6) to protect cells from swelling under stress. Taurine may enhance mitochondrial function and biogenesis. Recent research shows it maintains telomere length, reduces cellular senescence markers (p16, p21), and modulates the mTOR pathway.
Risks & Safety
5-HTP
Common
Nausea, diarrhea, stomach cramps.
Serious
Serotonin syndrome when combined with SSRIs, SNRIs, MAOIs, or tramadol — DO NOT combine without medical supervision.
Rare
Eosinophilia-myalgia syndrome (historical concern from contaminated L-tryptophan, not confirmed with modern 5-HTP).
Taurine
Common
Very few — taurine has an excellent safety profile. Mild digestive discomfort at very high doses.
Serious
None documented at standard supplemental doses. Safe up to 6000 mg daily in studies.
Rare
Drowsiness, lowered blood pressure.
Full Profiles
5-HTP →
5-Hydroxytryptophan is the immediate precursor to serotonin, derived from the seeds of Griffonia simplicifolia. By providing the rate-limiting intermediate in serotonin synthesis, 5-HTP effectively raises brain serotonin levels. Used for mood support, anxiety, sleep, and appetite control. More effective than L-Tryptophan because it bypasses the rate-limiting enzyme step.
Taurine →
An abundant amino acid in the brain that acts as a major inhibitory neuromodulator, antioxidant, and osmolyte (cell volume regulator). Despite its association with energy drinks, taurine is actually calming — it modulates GABA receptors and reduces neural excitability. Recent research has shown taurine supplementation reverses aging markers in multiple organ systems including the brain.