Last Updated: September 28 2022

5-HTP is the precursor to serotonin, the neurotransmitter sometimes touted to be responsible for happiness. 5-HTP is a simple way to increase brain serotonin levels by bypassing the rate-limiting step, and users reap either the rewards or the hazards of increased brain serotonin.

5-HTP is most often used for


5-HTP is a compound which gets converted into serotonin in the brain. Serotonin is one of the principal neurotransmitters involved in happiness and anti-depression.

5-HTP has been used with success to restore serotonin levels in those that may suffer from decreased serotonin levels, such as the depressed and those with high levels of body inflammation (typically seen in metabolic syndrome).

What else is 5-HTP known as?
Note that 5-HTP is also known as:
  • 5-hydroxytryptophan
  • serotonin precursor
Dosage information

A typical dose of 5-HTP is in the range of 300-500 mg, taken either once daily or in divided doses. Lower doses may also be effective, although usually when paired with other substances.

For the purpose of reducing food intake, 5-HTP should be taken with a meal as it increases satiety from food intake (rather than reducing appetite/hunger).

5-HTP should not be taken with any neurological drug that has been prescribed for antidepressant or other cognitive purposes unless cleared by a medical doctor. This is most important for SSRI usage, wherein the combination with 5-HTP is potentially lethal.

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      1.^Turner EH, Loftis JM, Blackwell ADSerotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophanPharmacol Ther.(2006 Mar)
      3.^Rondanelli M, Klersy C, Iadarola P, Monteferrario F, Opizzi ASatiety and amino-acid profile in overweight women after a new treatment using a natural plant extract sublingual spray formulationInt J Obes (Lond).(2009 Oct)
      7.^O'Neil MF, Moore NAAnimal models of depression: are there anyHum Psychopharmacol.(2003 Jun)
      8.^Ceci F, Cangiano C, Cairella M, Cascino A, Del Ben M, Muscaritoli M, Sibilia L, Rossi Fanelli FThe effects of oral 5-hydroxytryptophan administration on feeding behavior in obese adult female subjectsJ Neural Transm.(1989)
      9.^Cangiano C, Laviano A, Del Ben M, Preziosa I, Angelico F, Cascino A, Rossi-Fanelli FEffects of oral 5-hydroxy-tryptophan on energy intake and macronutrient selection in non-insulin dependent diabetic patientsInt J Obes Relat Metab Disord.(1998 Jul)
      10.^Cangiano C, Ceci F, Cascino A, Del Ben M, Laviano A, Muscaritoli M, Antonucci F, Rossi-Fanelli FEating behavior and adherence to dietary prescriptions in obese adult subjects treated with 5-hydroxytryptophanAm J Clin Nutr.(1992 Nov)
      11.^Cangiano C, Ceci F, Cairella M, Cascino A, Del Ben M, Laviano A, Muscaritoli M, Rossi-Fanelli FEffects of 5-hydroxytryptophan on eating behavior and adherence to dietary prescriptions in obese adult subjectsAdv Exp Med Biol.(1991)
      13.^Wurtman RJ, Wurtman JJBrain serotonin, carbohydrate-craving, obesity and depressionObes Res.(1995 Nov)
      20.^Jennifer M Loftis, Peter HauserThe phenomenology and treatment of interferon-induced depressionJ Affect Disord.(2004 Oct 15)
      21.^Bonaccorso S, Marino V, Puzella A, Pasquini M, Biondi M, Artini M, Almerighi C, Verkerk R, Meltzer H, Maes MIncreased depressive ratings in patients with hepatitis C receiving interferon-alpha-based immunotherapy are related to interferon-alpha-induced changes in the serotonergic systemJ Clin Psychopharmacol.(2002 Feb)
      22.^Shaw K, Turner J, Del Mar CAre tryptophan and 5-hydroxytryptophan effective treatments for depression? A meta-analysisAust N Z J Psychiatry.(2002 Aug)
      24.^Hinz M, Stein A, Uncini T5-HTP efficacy and contraindicationsNeuropsychiatr Dis Treat.(2012)
      25.^Hinz M, Stein A, Uncini TAmino acid management of Parkinson's disease: a case studyInt J Gen Med.(2011 Feb 28)
      26.^Hinz M, Stein A, Uncini TMonoamine depletion by reuptake inhibitorsDrug Healthc Patient Saf.(2011)
      27.^Shell W, Bullias D, Charuvastra E, May LA, Silver DSA randomized, placebo-controlled trial of an amino acid preparation on timing and quality of sleepAm J Ther.(2010 Mar-Apr)
      28.^Emanuele E, Bertona M, Minoretti P, Geroldi DAn open-label trial of L-5-hydroxytryptophan in subjects with romantic stressNeuro Endocrinol Lett.(2010)
      29.^Speroff L, Gass M, Constantine G, Olivier S; Study 315 InvestigatorsEfficacy and tolerability of desvenlafaxine succinate treatment for menopausal vasomotor symptoms: a randomized controlled trialObstet Gynecol.(2008 Jan)
      30.^Stearns V, Slack R, Greep N, Henry-Tilman R, Osborne M, Bunnell C, Ullmer L, Gallagher A, Cullen J, Gehan E, Hayes DF, Isaacs CParoxetine is an effective treatment for hot flashes: results from a prospective randomized clinical trialJ Clin Oncol.(2005 Oct 1)
      32.^Freedman RR, Wasson SMiniature hygrometric hot flash recorderFertil Steril.(2007 Aug)
      34.^Park SB, Coull JT, McShane RH, Young AH, Sahakian BJ, Robbins TW, Cowen PJTryptophan depletion in normal volunteers produces selective impairments in learning and memoryNeuropharmacology.(1994 Mar-Apr)
      35.^Oldman A, Walsh A, Salkovskis P, Fairburn CG, Cowen PJBiochemical and behavioural effects of acute tryptophan depletion in abstinent bulimic subjects: a pilot studyPsychol Med.(1995 Sep)
      37.^Klaassen T, Klumperbeek J, Deutz NE, van Praag HM, Griez EEffects of tryptophan depletion on anxiety and on panic provoked by carbon dioxide challengePsychiatry Res.(1998 Feb 27)
      39.^Schruers K, Klaassen T, Pols H, Overbeek T, Deutz NE, Griez EEffects of tryptophan depletion on carbon dioxide provoked panic in panic disorder patientsPsychiatry Res.(2000 Apr 10)
      40.^Schruers K, van Diest R, Overbeek T, Griez EAcute L-5-hydroxytryptophan administration inhibits carbon dioxide-induced panic in panic disorder patientsPsychiatry Res.(2002 Dec 30)
      42.^Bruni O, Ferri R, Miano S, Verrillo EL -5-Hydroxytryptophan treatment of sleep terrors in childrenEur J Pediatr.(2004 Jul)
      43.^Schruers K, van Diest R, Nicolson N, Griez EL-5-hydroxytryptophan induced increase in salivary cortisol in panic disorder patients and healthy volunteersPsychopharmacology (Berl).(2002 Jun)
      45.^Zhelyaskov DK, Levitt M, Udenfriend STryptophan derivatives as inhibitors of tyrosine hydroxylase in vivo and in vitroMol Pharmacol.(1968 Sep)
      49.^Ritvo ER, Yuwiler A, Geller E, Kales A, Rashkis S, Schicor A, Plotkin S, Axelrod R, Howard CEffects of L-dopa in autismJ Autism Child Schizophr.(1971 Apr-Jun)
      54.^Orlefors H, Sundin A, Lu L, Oberg K, Långström B, Eriksson B, Bergström MCarbidopa pretreatment improves image interpretation and visualisation of carcinoid tumours with 11C-5-hydroxytryptophan positron emission tomographyEur J Nucl Med Mol Imaging.(2006 Jan)
      55.^Bertoldi M, Gonsalvi M, Voltattorni CBGreen tea polyphenols: novel irreversible inhibitors of dopa decarboxylaseBiochem Biophys Res Commun.(2001 Jun 1)
      56.^Gustafsson BI, Tømmerås K, Nordrum I, Loennechen JP, Brunsvik A, Solligård E, Fossmark R, Bakke I, Syversen U, Waldum HLong-term serotonin administration induces heart valve disease in ratsCirculation.(2005 Mar 29)
      61.^Nardini M, De Stefano R, Iannuccelli M, Borghesi R, Battistini NTreatment of depression with L-5-hydroxytryptophan combined with chlorimipramine, a double-blind studyInt J Clin Pharmacol Res.(1983)
      62.^van der Horst-Schrivers AN, Post WJ, Kema IP, Links TP, Willemse PH, Wymenga AN, de Vries EGPersistent low urinary excretion of 5-HIAA is a marker for favourable survival during follow-up in patients with disseminated midgut carcinoid tumoursEur J Cancer.(2007 Dec)