The overriding objectives of this study are:

1. Primary outcomes:

   1. To confirm that administration of oral acetate increases the proportion of A. muciniphilia in the stool samples of patients with metastatic, castration-sensitive prostate cancer compared to a standard of care arm.
   2. To confirm tolerability and assess for side effects of oral acetate supplementation.

2. Secondary outcomes:

   1. To determine if increased counts of A. muciniphilia correlate with improved metabolic parameters and improved bone health.

For inclusion in this study, patients must fulfill all of the following criteria:

1. Men ≥18 years of age with histologically-proven metastatic castration-sensitive prostate adenocarcinoma planned to receive ADT (TNM stage Tany, Nany, M1) (see Appendix I).
2. Must have baseline imaging with 1) CT of the abdomen, and pelvis and bone scan or 2) PSMA PET scan

Patients fulfilling any of the following criteria are NOT eligible for participation in this study:

1. Age less than 18
2. Primary neuroendocrine prostate cancer
3. Treatment with ADT within the year leading up to enrolment
4. Planned or concurrent use of chromium supplementation for the study duration
5. Planned or concurrent use of apple cider vinegar supplementation for the study duration
6. Unable to provide informed consent or unable to understand or read the English language (unless accompanied by an interpreter)
7. Inadequate liver function (>2x upper limit of normal)
8. Any other condition, chronic disease, or lifestyle factor, that, in the opinion of the Qualified Investigator, may adversely affect the participant's ability to complete the study or its measures or pose significant risk to the participant
9. Use of antibiotics that cannot be discontinued for a washout period and remain off them for the duration of the trial

Our study protocol and analyses can be shared, but individual data will not.