Prostate-specific antigen (PSA) is a widely used biomarker for evaluating prostate health, often associated with conditions such as benign prostatic hyperplasia (BPH) and prostate cancer. PSA is not, however, a direct measure of disease, but rather a clinical marker influenced by underlying prostate biology. These processes include hormone-mediated signaling pathways, cellular proliferation, and inflammatory activity within prostate tissue. Prostate cancer remains one of the most prevalent cancers in men worldwide and is currently the second most commonly diagnosed cancer in men, contributing significantly to the number of global cancer cases each year. Many are initially identified through elevated PSA levels, making it a useful marker that should be interpreted within a broader context.
Beyond structural changes in the prostate, hormone signaling plays a central role in regulating PSA and overall prostate function. Testosterone can be converted into dihydrotestosterone (DHT) through the enzyme 5-alpha-reductase. DHT is a more potent androgen that activates the androgen receptor and increases PSA expression in prostate cells. At the same time, testosterone can also be converted into estrogen through aromatization, a process that tends to increase with age and may contribute to hormonal imbalance in the prostate. Estrogen metabolism has downstream effects, as different metabolites exert distinct actions in the body. Specifically, it has been shown to influence the ratio of 2-hydroxyestrone, considered less proliferative, to 16-hydroxyestrone, which can promote proliferative signaling. These pathways are regulated by cytochrome P450 enzymes, and are influenced by various compounds.
Diindolylmethane (DIM), derived from cruciferous vegetables, has been shown to influence several aspects of this complex system. Recent preclinical research shows that DIM promotes the formation of more favorable estrogen metabolites by inducing CYP enzymes, and may help support a healthier balance between testosterone and estrogen by reducing aromatization. In addition, DIM appears to exhibit androgen receptor antagonistic activity, interfering with DHT signaling and reducing PSA gene expression. Finally, DIM may also aid in reducing sex hormone-binding globulin (SHBG), which may help increase the availability of free testosterone. Together, these mechanisms provide a strong explanation as to how DIM may help support hormonal balance and prostate health in aging men.
A recent case report evaluated the effects of DIM supplementation in a 78-year-old male presenting with steadily rising PSA levels alongside declining testosterone. At baseline, his PSA was elevated at 4.6 ng/mL (reference range: 0.0 to 4.0 ng/mL), while total testosterone measured 436 ng/dL and free testosterone was low at 3.5 pg/mL (reference range: 6.6 to 18.1 pg/mL). Taken together, these findings suggested an unfavorable hormonal pattern occurring in parallel with elevated PSA. His medical history included benign prostatic hyperplasia, hypertension, hyperlipidemia, coronary artery disease, and depression. He was also taking several medications, including a 5-alpha-reductase inhibitor, an angiotensin receptor blocker, a statin, an antidepressant, a phosphodiesterase-5 inhibitor, and an alpha-1 blocker, in addition to an over-the-counter cholesterol-lowering supplement.
A targeted protocol was implemented under the supervision of a clinical nutritionist, consisting of 100 mg of DIM supplementation per day for approximately five months, with continued use beyond the initial protocol. At the same time, he was encouraged to discontinue the cholesterol-lowering supplement without tapering, given cholesterol’s role as a precursor for steroid hormone synthesis and its potential impact on testosterone production, with care coordinated alongside his medical providers. This adjustment was intended to work alongside DIM as part of a broader strategy to support hormonal balance.
After starting the intervention, changes were observed relatively quickly. Within roughly three months, PSA dropped from 4.6 to 2.4 ng/mL, representing nearly a 50% reduction. Over that same period, total testosterone increased from 436 to 615 ng/dL, while free testosterone rose from 3.5 to 7.3 pg/mL. With continued adherence, these clinically-relevant improvements were sustained at the four-month mark. PSA decreased slightly further to 2.2 ng/mL, while total testosterone continued to rise to 652 ng/dL. Free testosterone remained meaningfully higher than baseline, with some expected variability at follow-up.
Alongside these lab changes, the patient reported feeling better overall, noting improvements in energy, libido, and general well-being. He also shared that this approach helped him avoid a prostate biopsy that had previously been recommended, which was a meaningful outcome for him.
This case highlights how targeting underlying hormone pathways may play a meaningful role in supporting prostate health. In this patient, DIM supplementation, alongside discontinuation of a cholesterol lowering supplement, was associated with a reduction in PSA and an improvement in androgen status over a relatively short period of time. These changes occurred alongside improvements in energy, libido, and overall well-being, suggesting a broader shift in hormonal balance rather than an isolated effect on a single biomarker. At a deeper level, this may reflect combined effects on estrogen metabolism, reduced aromatization, and modulation of androgen receptor signaling, all of which play a role in PSA regulation. While this is a single case and cannot be generalized, the outcome aligns with known mechanisms of DIM. Larger, more robust clinical trials are needed to further elucidate its role in prostate health. Together, these findings support the idea that addressing hormone balance may be a useful complementary approach in men with elevated PSA.
Learn more about men’s health:
The Hidden Connection Between Erectile Dysfunction and Antioxidant Status
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By Jesse Martin, MS
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