Bulbine natalensis is an herb native to southern Africa that is touted for its testosterone and libido-boosting effects.
It's also found in many testosterone boosters.
Bulbine natalensis contains several beneficial compounds, including saponins, anthraquinones, tannins, cardiac glycosides and alkaloids. In addition to helping boost testosterone in men, this herb may also have an effect on several other reproductive hormones. Recent scientific studies have also shed some light on the possibility of Bulbine natalensis treating dry skin and wounds (1).
Bulbine natalensis may boost testosterone levels, a.k.a., the male sex hormone. In a study performed on male laboratory rats, four separate groups were given either a placebo or doses of 25, 50 or 100 mg/kg body weight of aqueous extract of bulbine stem. At the end of the 14-day study, the rats in the 50 mg/kg group showed the highest anabolizing and androgenic activities (2). This group exhibited the largest increase in testicular and serum testosterone concentration, testicular acid phosphatase activity, serum follicle stimulating and luteinizing hormone concentrations. The study was published in the peer-reviewed medical journal, Pharmaceutical Biology in 2010.
In another study, testosterone levels in rats were tested again, and the group given 50mg/kg of bulbine extract experienced an astounding 346 percent increase in testosterone.
Interestingly, the 100mg/kg dosage actually lowered serum testosterone levels (3).
Bulbine natalensis increases libido. In a study published in the International Journal of Andrology, researchers noted that rats given oral doses of 25 and 50 mg/kg of Bulbine natalensis aqueous extract, demonstrated an increase in sexual behavior. Phytochemical compounds present in the extract, including saponins, cardiac glycoside, tannins, alkaloids and anthraquinones are what researchers believe are responsible for an increase in such behavior as mount frequency, ejaculatory latency, ejaculation frequency and serum testosterone and luteinizing hormone concentrations.
At the end of the seven-day study, researchers confidently revealed that the aqueous extract at doses of 25 and 50mg/kg enhanced mating activity and fertility in male rates due to increased libido as well as the levels of reproductive hormones (4).
Researchers are optimistic that this aqueous extract may one day be effective in the management of premature ejaculation, erectile dysfunction and low libido in males (5).
Bulbine natalensis’ effect on other hormones. In addition to raising testosterone levels, extracts of this herb significantly increased levels of progesterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the 25 and 50mg/kg groups (6). These hormones all play a vital role in male reproductive ability.
While progesterone is frequently referred to as a female hormone, it plays an important role in men. Progesterone is the precursor to testosterone and helps to counteract estrogen in the male body. It regulates vital sperm functions such as capacitation (the process in which the outer membrane of the head of the sperm is removed, making it ready to penetrate and fertilize the egg) and influences spermiogenesis (sperm production) and testosterone production (7).
Luteinizing hormone (LH) is produced by the pituitary gland and aids the reproductive system in both men and women. Its primary role in men is to bind to receptors on Leydig cells, stimulating the production of testosterone and the production of sperm. Low levels of LH can cause infertility.
Follicle-stimulating hormone (FSH) is also produced by the pituitary gland, and its role is to stimulate sperm production.
Bulbine natalensis may be an effective topical treatment for wounds. Indigenous plants have long been used in South Africa to treat a number of skin ailments. Researchers who studied the ability of Bulbine natalensis and Bulbine frutescens (another popular indigenous plant from South Africa) to heal cutaneous wounds in pigs were optimistic about their findings.
At the end of the 16-day evaluation period, researchers discovered that the wounds treated with leaf gel extracts from both plants, healed much faster than wounds that were left untreated. In addition, they noted an increase in the skin's tensile strength (breaking point), protein and DNA content.
Researchers are interested in further investigating the ability of Bulbine natalensis to heal wounds and its potential for being developed into a low-cost, effective topical wound treatment (8).
Researchers warn that the use of Bulbine natalensis in doses of 25, 50, and 100mg/kg adversely affects liver and kidney function in rats (9).
While the extract of this herb is capable of increasing testosterone, libido and the levels of reproductive hormones in rats, it also comes with several dangerous side effects.
Bulbine natalensis causes liver changes. One toxicology study revealed that rats given oral doses of 25, 50, and 100mg/kg had altered liver enzymes as well as histological changes in the liver.
Bulbine natalensis also affects kidney function by causing distortions in kidney structures including the proximal tubules and convoluted tubules.
Bulbine natalensis raises the risk of atherosclerosis (clogged arteries). All the doses increased cholesterol and triglyceride levels after two weeks of regular use, predisposing the animals to atherosclerosis. Early evidence suggests that just like a steroid cycle, the longer it’s used, the more problematic it becomes.
There has only been one study testing the dosage and safety of a Bulbine natalensis supplement in humans. The study evaluated the supplement ProLensis™ and it was given to a group of men for 28 days. The dosage given was 325 mg in the morning and 325 mg six hours after the first dose. It is important to note that this equates to a dosage of approximately 8 mg/kg of bodyweight which is significantly lower than the dosages used in the rat studies.
At the end of the study, researchers found that this dosage did not affect 27 of 29 variables such as heart rate, blood pressure, EKG, and kidney, liver and hematological biomarkers (10).
Researchers stress the need for more in-depth studies on the efficacy and side effects in humans.
Bulbine natalensis is an herb that has shown to have impressive testosterone and libido-boosting effects in rats. Early research also shows promise in its ability to heal wounds when applied topically.
Studies of this herb have been limited to animals, and researchers warn that due to its link to potentially serious liver and kidney side effects, it is best to hold off using Bulbine natalensis supplements until more studies have been carried out.