What is DHT?
An enzyme called 5-alpha-reductase, which resides in the prostate, transforms testosterone into another hormone called dihydrotestosterone (DHT). DHT is involved in noncancerous growth of the prostate (BPH) as well as the development of prostate cancer. DHT stimulates growth of prostate cells, and is reportedly as much as 30 times more potent than testosterone. The result of this stimulation is an enlarged prostate and a narrowed urethral channel, which then results in urination problems.
Factors That Decrease Production of DHT
Elevated levels of DHT are not the result of high testosterone levels, but a greater conversion of testosterone to DHT. Therefore, anything that has an impact on the production and/or activity of 5-alpha-reductase has an effect on this conversion and the levels of DHT. Natural and lifestyle factors that can inhibit production of DHT include:
 |
Saw palmetto, which reduces DHT by blocking 5-alpha-reductase activity in the body and also by blocking receptor sites on cell membranes that the cells need to absorb DHT Read more on saw palmetto |
 |
Pygeum extract, which has active ingredients called phytosterols that inhibit the production of DHT. This herb also reduces the number of receptor sites where the DHT can attach to cells. Read more on pygeum |
 |
Pumpkin seed oil, which helps reduce DHT by inhibiting the activity of 5-alpha-reductase. Read more on pumpkin seed oil |
 |
Green tea, a potent antioxidant that also reduces DHT and cholesterol levels. Read more on green tea |
 |
Beta-sitosterol, which contains a mixture of phytosterols that can block DHT. Beta-sitosterol also lowers cholesterol levels, which in turn inhibits the production of DHT. Read more on Beta sitosterol |
 |
Keeping cholesterol levels in check. A healthy cholesterol level is between 160 and 200 mg/dL. More on cholesterol and prostate health |
 |
Lysine supplements, which can help enhance the DHT-blocking ability of other supplements, such as saw palmetto and pygeum. Lysine alone, however, does not block 5-alpha-reductase. Read more on Lysine supplements |
Factors That May Increase Production of DHT
Creatine
Elevated levels of the androgen dihydrotestosterone (DHT) are associated with an increased risk of benign prostatic hyperplasia (BPH) and prostate cancer. Among the numerous factors that may promote production of DHT is creatine, a chemical that is normally produced in the body and found primarily in the muscles. Although bodybuilders and other athletes frequently use creatine supplements to enhance high-intensity performance and promote muscle growth, a side effect of creatine supplementation is a rise in DHT.
In a double-blind, placebo-controlled study recently published in the Clinical Journal of Sports Medicine, for example, 20 college-aged rugby players were divided into two groups. One group took either 25 g/day of creatine plus 25 g/day of glucose for seven days followed by 14 days of 5 g/day of creatine plus 25 g/day of glucose; the other group took placebo (50 g/day of glucose) for seven days followed by 30 g/day of glucose for 14 days.
In the men who took creatine, testosterone levels did not change throughout the 21 days of the study. However, DHT levels increased by 56 percent after 7 days of creatine supplementation and remained 40 percent above baseline after 14 days at the lower dose. (van der Merwe 2009)
Hormones
Several other agents are associated with an increase in DHT levels. Prolactin, a hormone and protein released by the pituitary gland, is known to stimulate activity of 5-alpha-reductase, which in turn can result in elevated DHT levels. (Takeyama 1986) Prolactin levels can be increased by stress and use of some antipsychotic medications.
Two hormones that are most dominant in females—oxytocin and human chorionic gonadotropin–may also cause a rise in DHT levels. Animal studies indicate that the hormones can increase concentrations of DHT in rat testis. (Sawada T 1998)
Use of a dopamine agonist called cabergoline, a medication used to treat hyperprolactinemia (excessive levels of prolactin), raised both DHT and testosterone levels in a group of men who were being treated for sexual problems related to hyperprolactinemia. (De Rosa 1998) A report in the journal Diabetes notes that obesity and insulin resistance are associated with an increase in the activity of 5-alpha-reductase in both men and women. (Tomlinson 2008)
Testosterone
Some websites suggest that using substances that raise testosterone levels will also increase levels of DHT. However, agents that increase testosterone levels do not automatically raise DHT levels. High levels of DHT are not the result of elevated testosterone levels, but rather a high rate of conversion of testosterone to DHT. The enzyme responsible for that conversion is 5-alpha-reductase: anything that increases the activity of 5-alpha-reductase has an impact on this conversion, resulting in elevated DHT levels.
Finasteride, DHT and Prostate Cancer
Finasteride (Proscar) is a 5-alpha-reductase inhibitor used to treat benign prostatic hypertrophy (BPH). When scientists noticed that finasteride inhibited the conversion of testosterone to DHT, they initiated a study called the Prostate Cancer Prevention Trial (PCPT) in the early 1990s. (Thompson 2003) The trial evaluated 18,000 men age 55 and older and lasted seven years. The results, published in 2003, found that:
- 18.4 percent of men who took finasteride developed prostate cancer over the study’s course
- 24.4 percent who took placebo developed prostate cancer over the study’s course
- Men in the finasteride group had a 28 percent reduction in prevalence in prostate cancer and a smaller prostate volume than men in the placebo group
However:
- The rate of high-grade cancers was greater in the finasteride group (6.5%) than in the placebo group (5.1%). The reason for this is unknown.
- Most cancers in the finasteride group were small and localized.
The incidence of high grade cancers in the finasteride group during this study is one reason medical professionals are reluctant in most instances to prescribe finasteride for prostate cancer treatment.
Since the PCPT, subsequent studies have reinterpreted the findings. Some research confirmed the reduced risk of prostate cancer (Thompson 2008), while others re-examined the increased risk of high-grade tumors and determined that finasteride actually reduced the risk of developing aggressive cancer when compared with placebo. (Pinsky 2008; Redman 2008)
However, two physicians from Johns Hopkins evaluated all the findings and note that the decrease in prostate cancer related to finasteride was much smaller than originally reporte and not statistically significant. Therefore, they believe finasteride will not significantly help reduce the risk of prostate cancer among men who are monitored regularly and who have a biopsy when they experience an elevated PSA or abnormal digital rectal exam. They recommend men not take 5-alpha-reductase inhibitors as a means to prevent prostate cancer, and warn that because 5-alpha reductase inhibitors reduce PSA levels by about 50 percent, men should multiply their PSA numbers during the first two years they use the drugs, by 2.3 for years 2 through 7, and by 2.5 for 7 years or longer to get a more accurate indication of their prostate cancer risk that may require a biopsy. (Johns Hopkins)
See also
The Prostate Diet
6 Pillars of Prostate Health
References
De Rosa M et al. Cabergoline treatment rapidly improves gonadal function in hyperprolactinemic males: a comparison with bromocriptine. Eur J Endocrinol1998 Mar; 138(3): 286-93
Johns Hopkins, Prostate Disorders, 2009
Redman MW et al. Finasteride does not increase the risk of high-grade prostate cancer: a bias-adjusted modeling approach. Cancer Prev Res (Phila) 2008 Aug; 1(3): 174-81
Sawada T et al. Effects of Oxytocin and Prostaglandin F2α on Androgen Production of Adult Rat Testis In Vivo. Prostaglandins 1998 Feb; 55(2030: 121-26
Takeyama M et al. Stimulatory effect of prolactin on luteinizing hormone-induced testicular 5 alpha-reductase activity in hypophysectomized adult rats.Endocrinology 1986 Jun; 118(6): 2268-75
Thompson IM et al. Does the level of prostate cancer risk affect cancer prevention with finasteride? Urology 2008 May; 71(5): 854-57
Tomlinson JW et al. Impaired glucose tolerance and insulin resistance are associated with increased adipose 11-beta-hydroxysteroid dehydrogenase type 1 expression and elevated hepatic 5-alpha-reductase activity. Diabetes 2008; 57(10): 2652-60
Van der Merwe et al. Three weeks of creatine monohydrate supplementation affects dihydrotestosterone to testosterone ratio in college-aged rugby players.Clin J Sport Med 2009 Sep; 19(5): 399-404
