Oral Bioavailability of Two Melatonin Supplements
Condition: Bioavailability
Study type: Interventional

Summary: 
      Results from several clinical studies show that orally administered melatonin has low
      bioavailability and a very short half-life. Phenyl capsaicin, a synthetic analogue of
      capsaicin, might increase its bioavailability by inhibiting the enzymes involved in its
      hepatic metabolism.

      Thus, the hypothesis of the present study is that the administration of melatonin supplement
      with phenyl capsaicin presents greater bioavailability than a melatonin supplement that does
      not contain phenyl capsaicin.
    

Detailed description: 
      Melatonin is an endogenous indolamine that regulates many physiological functions such as
      reproduction, temperature, mood, bone growth or the immune system. However, since its
      production is closely related to the light/dark cycle, melatonin is considered one of the
      main chronobiotic agents that modulates circadian rhythms.

      For this reason, in recent years there has been increased interest in the exogenous use of
      melatonin to address problems of insomnia and circadian rhythm disorders such as jet lag
      syndrome or shift work. Although many studies have demonstrated the effectiveness of
      melatonin in treating sleep disorders, pharmacokinetic studies show that it has poor oral
      bioavailability and a very short half-life. So, new strategies and studies are necessary to
      increase the low bioavailability of melatonin.

      In this context, it has been shown that phenyl capsaicin, a synthetic analogue of capsaicin,
      might increase melatonin's bioavailability by inhibiting Cytochrome P450 liver enzymes, which
      are involved in its metabolism. Therefore, the main objective of this study is to quantify
      and compare the oral bioavailability between a melatonin supplement with phenyl capsaicin and
      another melatonin supplement that does not contain phenyl capsaicin.

      The secondary objectives of the study are to determine the pharmacokinetic parameters:

        -  Maximum plasma concentration (Cmax).

        -  Time for maximum plasma concentration (Tmax).

        -  Half-life (T1/2).

        -  Area Under the Curve (AUC 0-inf) of plasma melatonin levels

      During the study there will be 3 visits: a preselection visit (V0), a visit for the first
      postprandial study (V1) and after one week washing period, a visit for the second
      postprandial study (V2).
    

Intervention name(s): Melatonin with phenyl capsaicin; Melatonin without phenyl capsaicin
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): Blood samples will be collected at different time points following the oral administration of the melatonin supplement with phenyl capsaicin; Blood samples will be collected at different time points following the oral administration of the melatonin supplement without phenyl capsaicin
Intervention MeSH terms: Melatonin; Capsaicin
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Crossover, Randomized, Triple-Blind Study
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Other
Keywords: Melatonin; Phenyl capsaicin; Bioenhancer