Objective: to review the literature for reported cases of Tryptophan increasing or decreasing sexual disinhibition, as well as for possible explanation of this phenomenon. Method: We undertook a literature review through the PubMed index, using the key words 'Tryptophan' and 'sexual'. We reviewed 6 articles featuring 15 cases. Where available, we noted and tabulated certain parameters for cases of sexuality increased or decreased by Tryptophan. Results: We found 13 cases where sexuality had been increased by Tryptophan. The dose was 5gm/day or above in 9 cases, and 3gm/day in 4 cases. We found 2 cases where sexuality had been decreased by Tryptophan. In both cases the dose was 3gm/day. Conclusion: Tryptophan can alter sexuality in both directions through changing serotonin availability in the brain. The direction of the effect appears to be dependent on the dose but also is affected by serotonin state prior to treatment. Tryptophan increases serotonin availability in the brain, an effect which might be reversed in higher doses. The proper dose for treatment of sexual disinhibition seems to be 2000mg/day. This phenomenon can theoretically apply on any presumed serotonin deficiency state including depression and anxiety, as well as sexual disinihibition.