In this 2021 research review authors examine clinical and preclinical research for the use of indoles derived from cruciferous vegetables. Suggesting that daily ingestion of kg quantities of Brussels sprouts is required to produce in vivo levels of DIM achievable by supplementation.
References:
Williams DE. Indoles Derived From Glucobrassicin: Cancer Chemoprevention by Indole-3-Carbinol and 3,3′-Diindolylmethane. Front Nutr. 2021 Oct 1;8:734334. doi: 10.3389/fnut.2021.734334. PMID: 34660663; PMCID: PMC8517077.