How to Stop 5-HTP Decarboxylation in Blood

Occurring naturally within the brain, 5-Hydroxytryptophan (5-HTP) serves as an intermediate molecule in the conversion of dietary amino acid tryptophan to the neurotransmitter serotonin. It is also available as a supplement. Because 5-HTP functions as a serotonin precursor and readily crosses the blood-brain barrier, it can increase brain serotonin levels. Low brain serotonin levels are thought to play a role in a number of mood and other disorders.

Upon ingestion, some of 5-HTP is enzymatically converted to serotonin by liver decarboxylases, before reaching the brain. Since serotonin is unable to cross the blood-brain barrier, 5-HTP effectiveness may be reduced. Peripheral inhibition of these decarboxylases, therefore, increases 5-HTP availability to the brain.

Instructions

Decarboxylase inhibition

• 1

  Relate to your physician your interest in using 5-HTP concomitantly with a peripheral carboxylase inhibitor (PDI). In U.S., PDIs are available only by prescription. The most commonly available PDI is Lodosyn (Carbidopa).

  While coadmistration of 5-HPT and carbidopa does seem to increase 5-HTP blood levels, there is no conclusive evidence that this practice improves 5-HTP efficacy. A somewhat dated review of literature report, published in 1987 in Journal of Clinical Psychopharmacology, does indicate, however, that some of the common side effects of 5-HTP like nausea, vomiting and diarrhea may be reduced with carbidopa.

• 2

  Purchase the 5-HTP supplement and fill the carbidopa prescription—assuming one was obtained.

• 3

  Only if approved by a physician, take the 5-HTP supplement according to label directions and the carbidopa according to physician’s instructions. To achieve the desired effect (increased 5-HTP brain penetration), the two substances must be administered at the same time.

  The typical dosage for 5-HTP is 200 to 300 mg total per day in divided doses. In a more recent meta-analysis report on 5-HTP, published in March 2006 issue of Pharmacology and Therapeutics, the authors suggest that a dosing frequency of three times per day may be the most effective. Carbidopa is generally initiated at 25 mg three to four times per day, according Rxlist.com.