General Info 

   Metabolic Role 





Dietary Supplement

HTML version Author: Kimberly Dick   

Tryptophan has often been hyped as "nature's prozac" or "nature's serotonin solution." While certainly an exaggeration, these extravagant claims have some basis in fact.

Serotonin deficiency is often a major factor in depression, anxiety, sleep disturbances, and weight gain, to name a few. Simply supplementing serotonin when there is a deficiency would appear to be the easiest solution; however, since serotonin cannot pass through the blood-brain barrier, direct supplementation with serontonin is in fact ineffective.

Most antidepressant drugs available today fall into the category of Selective Serotonin Reuptake Inhibitors (SSRIs) such as Prozac, Zoloft and Paxil. These drugs work by preventing the excessive uptake of serotonin in the brain, leaving more available in the synapses between neurons. However, many of these drugs have considerable side effects, in addition to being fairly expensive.

Unlike serotonin, tryptophan (or more accurately, its breakdown product 5-hydroxytryptophan) can pass through the blood-brain barrier. Thus supplementation of tryptophan would appear to be a simple and natural alternative to SSRI drugs. Since tryptophan can be cheaply produced and is not regulated as a drug, it is a much cheaper alternative. As well, it does not have the side effects of many drugs as it is naturally occurring in the body.

Tryptophan on its own works best in depression cases where psychobiologic arousal is high, and serotonin production is inadequate to balance the effects of dopamine and norepinephrine - resulting in a anxious, agitated state. For more apathetic, vegetative depressive cases, tryptophan supplementation is more effective when combined with supplementation of tyrosine, a precursor to dopamine/norepinephrine.

Serotonin deficiency has been implicated in cases of obesity, as it is associated with the brain's perception of hunger and satiety. Excessive intake of sugars and other carbohydrates is known to increase brain serotonin levels. By increasing serotonin levels, tryptophan can function as an appetite suppressant at low doses, and is sometimes very effective for weight loss.

As well, tryptophan has been successfully used as a sleep aid. Serotonin does play a role in sleep regulation, but more importantly, serotonin is the precursor to melatonin, a hormone crucial to the sleep cycle. On its own, melatonin supplementation has been shown to be an effective treatment for insomnia; however, combining melatonin with tryptophan may prove even more effective.

The compound 5-hydroxytryptophan (5-HTP) is the intermediate product in the conversion of tryptophan to serotonin. It was first offered as an over-the-counter supplement in 1994, and is marketed as a natural antidepressant. Since tryptophan is still banned by the FDA and is available in the United States only by prescription, 5-HTP has been offered as an alternative.

Since it is a direct precursor to serotonin, 5-HTP is considerably more active than tryptophan. It is thought to have effectiveness comparable to many prescription antidepressant drugs.

Unlike tryptophan, which was and still is produced in large quantities in vats of bacteria, 5-HTP is generally extracted from the Griffonia seed. It can be and sometimes is produced synthetically from tryptophan, but it is generally cheaper to extract it naturally. This allows 5-HTP to be offered at a more reasonable price, although still considerably higher than tryptophan was when it was offered as a nutritional supplement.

At the present time little research has been done on 5-HTP, and as such its effectiveness for various conditions is still unknown. Early research has suggested that it will be most effective in combination with other drugs and nutrients. It is expected that with time 5-HTP will become a widely used and effective supplement.

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