This is a somewhat difficult question to answer. The supplements that we have used in clinical studies and recommended to fellow investigators are: Avmacol (Nutramax Laboratories, containing GR + myrosinase) and Crucera-SGS (Thorne Research, containing GR alone). These, and other high quality supplements use TrueBroc® as a source of GR. I trust and endorse TrueBroc® since it is made, by the company I co-founded almost 25 years ago and have been consulting for since my retirement from JHU. Furthermore, I have personally tested it, and supervised its repeated 3rd party laboratory testing. We started using supplements in our clinical studies a number of years ago precisely because there are now some good, consistent, and safe supplements on the market. Consistency is really crucial as studies need to be carried out on quality products that deliver standardized amounts of key ingredients with minimal batch-to-batch variability. This is a standard that we, as an academic laboratory, could not hope to maintain forever, but it is something that diligent and conscientious supplement producers can readily accomplish. Remember that broccoli itself is highly variable with respect to the concentration of these plant compounds, so just seeing products that say they contain broccoli does not mean that they have active ingredients, nor does it indicate how much they contain or guarantee that to the consumer. This is a problem that has plagued the supplement industry for some time now. We have analyzed many supplements over the years, and there are some very poor supplements. Many of them are terrible in that they do not contain what they say they contain, they contain far less, or even only trace amounts, or they contain materials that are not even broccoli or related to it.

Absolutely! However, we have only tested a small fraction of the hundreds of supplements that represent themselves as containing meaningful amounts of sulforaphane or sulforaphane-producing compounds — SF, GR, GR + myrosinase, broccoli, broccoli sprouts, or broccoli seeds. Remember that GR (glucoraphanin) plus active myrosinase (an enzyme) produces SF (sulforaphane).

Oxidative stress is thought to be at the root of many diseases and pathologies OR to be a consequence of those conditions OR both. Many classic antioxidants (e.g. vitamin C, tocopherols or vitamin E, and beta carotene) act directly by terminating chain reactions initiated by free radicals or by directly quenching oxidants or reactive oxygen species. These are direct antioxidants – they directly, and sacrificially prevent oxidation. In contrast, sulforaphane induces or up-regulates a very wide range of protective enzymes in the body. Many of these are directly involved in countering oxidative stress. These include the enzymes controlling production of the body’s most ubiquitous and concentrated antioxidant, glutathione (or GSH). Sulforaphane does not directly quench or inhibit oxidation since it does not have what chemists call “redox activity”. Rather, it enhances and increases many [direct] antioxidants that in turn protect cells from oxidative stress. Thus, we call sulforaphane an indirect antioxidant. https://static.wixstatic.com/media/undefined The immediate and direct antioxidant power of one serving of broccoli sprouts is similar to one serving of orange juice, green tea, or blueberries (0 days; left panel). One day later, sulforaphane-rich broccoli sprouts are very powerful indirect antioxidants (8 million units per serving; right panel). In contrast, the other foods retain only very weak indirect antioxidant activity (thousands of units per serving). Notably, broccoli sprouts still retain one half of their high indirect antioxidant potency, even 96 hours later.