for people ages 18 years and up (full criteria)
healthy people welcome
at UC Davis
study started
estimated completion



The purpose of this study is to measure oil production of the face, facial properties, and gut bacteria in people being given oral probiotics. Probiotic supplements contain active cultures of bacteria that are thought to be beneficial to human health.The investigators want to find out if probiotics taken by mouth alter the bacteria in subject's gut and subject's skin oil production compared to a placebo. This is a single blind study and subject may receive a probiotic or a placebo for the first half of the study and a placebo or a probiotic for the second half of the study. Subject will not know what was given to participants.


Antibiotics are widely used within dermatology for the treatment of chronic skin conditions such as acne, rosacea, and atopic dermatitis. Previous studies have shown that oral probiotics may be beneficial for skin disesaes such as atopic dermatitis and acne, but a mechanism for how the gut communicates to the skin remains elusive.

The balance between short chain fatty acids and long chain fatty acids has been proposed as one factor in how bacteria in the gut are able to communicate with the rest of the body. Studies in Dr. Sivamani's lab have shown that subjects with acne have a reduced level of short chain fatty acids in their blood when compared to age-matched control (unpublished).

The aim of this study is to understand how oral probiotics may alter the gut microbiome and if they can augment the short chain fatty acids in the blood lipidome. Ultimately, the investigator's goal is to find suitable alternatives for the use of antibiotics in the treatment of chronic skin conditions so that the amount of antibiotics that are in use can be reduced.


Gut MicrobiomeSkin MicrobiomeGut LipidomeSkin LipidomeBlood LipidomeProbiotic


You can join if…

Open to people ages 18 years and up

• 18 years of age or older

You CAN'T join if...

  • Those on oral antibiotics within a month of initiating the study.
  • Subjects must have no history of diabetes, known cardiovascular disease, known immunocompromised condition, malignancy, kidney disease, or chronic steroid use.
  • Subjects must have no history or diagnosis of gastrointestinal inflammatory diseases.
  • Those with BMI higher than 30 kg/m²
  • Those on topical medications to the face such as retinoids or antibiotics who are not willing or medical unable (in the judgement of the investigator) to discontinue use for two weeks prior to the study and for the duration of study participation.
  • Those that have undergone a change in hormonally based therapies, such as but not limited to oral contraceptive pills or progesterone based pills within the last two months. Progesterone releasing IUDs are considered hormone releasing therapy.
  • Use of medications that alter blood lipids, such as statins and anti-hyperlipidemic medications
  • Current tobacco smokers, OR those that have smoked tobacco over the past year, OR a 5 year-pack year history of smoking tobacco
  • Pregnant women
  • Prisoners
  • Adults unable to consent


  • UC Davis Department of Dermatology accepting new patients
    SacramentoCalifornia95816United States


accepting new patients
Start Date
Completion Date
University of California, Davis
Study Type
Last Updated