Antioxidant Bioavailability

  • days left to enroll
  • participants needed
  • sponsor
    Natural Immune Systems Inc
Updated on 9 July 2021


A small cross-over trial on 3 different doses of liposomal vitamin C, comparing vitamin C uptake and downstream effects when 24 people consume 1, 2, and 5 grams on different test days, compared to placebo.


A randomized, cross-over study design will be used to evaluate the effects of consumption of 4 different doses of liposomal vitamin C (0, 1, 2, and 5 grams). The study is of 5 weeks' duration, with evaluation of a different dose at each of week 1, week 3 and week 5 with a one week washout between each dose.

Condition Pharmacokinetic aspects, Pharmacokinetics
Treatment Placebo, Liposomal vitamin C, 1 gram, Liposomal vitamin C, 2 grams, Liposomal vitamin C, 5 grams
Clinical Study IdentifierNCT04463030
SponsorNatural Immune Systems Inc
Last Modified on9 July 2021


Yes No Not Sure

Inclusion Criteria

Adult people of either gender
BMI between 18.0 and 34.9 (inclusive)
Willing to abstain from coffee, tea, and soft-drinks for at least one hour prior to a clinic visit
Willing to abstain from alcohol for at least 12 hours prior to a clinic visit
Willing to maintain a consistent habit of abstaining from exercising, tobacco use, and nutritional supplements on the morning of a study visit

Exclusion Criteria

Cancer during past 12 months
Chemotherapy during past 12 months
Significant active uncontrolled illness (such as lymphoma, liver disease, kidney failure, heart failure)
Previous major surgery to stomach or intestines [(absorption of test product may be altered) minor surgery is not a problem, including appendix and gallbladder removal]
Currently taking nutritional supplements judged by the study coordinator to negate or camouflage the effects of the test product
Food allergies related to ingredients in test product
Women who are pregnant, nursing, or trying to become pregnant
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Additional screening procedures may be conducted by the study team before you can be confirmed eligible to participate.

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If you are confirmed eligible after full screening, you will be required to understand and sign the informed consent if you decide to enroll in the study. Once enrolled you may be asked to make scheduled visits over a period of time.

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Complete your scheduled study participation activities and then you are done. You may receive summary of study results if provided by the sponsor.

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