A study in the journal Phytotherapy Research reported that the herbal extract fenugreek boosted libido in 82% of men who consumed the dietary supplement in the six-week study.
In addition, 63% of the men taking the fenugreek noted an improvement in the quality of sexual performance and 67% of men indicated the herbal extract enhanced their sexual recovery time. 
Fenugreek, a plant whose seeds are used as a spice in Indian, African and Arabic food preparation, has been studied in the past for its effects in blood sugar maintenance in diabetics and its cholesterol-lowering effects among those with hyperlipidemia (high cholesterol and high triglycerides).
Fenugreek seeds are rich in a chemical compound known as saponins. According to the study authors, one of the common saponins found in fenugreek is diosgenin, a steroid-like precursor for the synthesis of a number of sex hormones.
Deep Dive into Fenugreek's Libido Benefits
In the study, 54 men with an average age of 41 were enrolled and divided into two groups.
Twenty-seven of the men received twice-daily doses of 300 mg of fenugreek combined with 17 mg of magnesium, 15 mg of zinc and 5 mg of pyridoxine (the brand name of the fenugreek used in the study is Testofen).
The other 27 men received placebo capsules (rice bran) that were similar in appearance to the fenugreek. Neither group was aware of the respective capsule ingredients.
The men selected for the study were considered healthy but overweight adults with low self-reported libido (sexual interest) — a condition that affects one out of every five male adults.
The men were all in stable sexual relationships, reported being sexually active for at least the past six months, and did not have erectile dysfunction.
The study authors noted, “The cause of low sexual drives is not always obvious. It can be the result of psychological issues, physical conditions or combinations of a number of other factors.
Psychological factors can include stress, distractions, depression, abuse or trauma as well as body image issues. On a physiological level, factors that disrupt normal hormonal balance are most likely caused by low levels of testosterone, poor fitness, being overweight or obese, malnourished, excessive alcohol intake, chronic stress (adrenal depletion) or other endocrine issues such as hypothyroidism, diabetes and hyperprolactinaemia.”
At the outset of the research program and again at three weeks and six weeks thereafter, the study subjects completed a commonly used sexual satisfaction survey known as the Derogatis interview for sexual functioning-self report, or DISF-SR for short.
The participants also completed another survey at the end of the study called the Likert scale of improvement. In addition, at these same intervals the researchers drew blood samples to examine the participants’ hormone levels.
Both groups recorded similar baseline scores on the DISR-SR questionnaire. However, at three weeks and six weeks, two-thirds of the fenugreek group reported statistically significant improvements on nearly all of the questionnaire sections (including an average 20% improvement in self-reported arousal and orgasm).
By contrast, the placebo group showed statistically significant declines on most of the questionnaire sections. The most pronounced improvements registered by the fenugreek group were recorded after six weeks of the fenugreek/mineral regimen.
Interestingly, in reviewing the blood samples the study team found no significant changes in the evaluated hormones (testosterone and prolactin) and no significant hormonal differences between the two groups despite the notable jump in libido among the fenugreek group.
The researchers had speculated that improvement in self-reported libido might be correlated with higher levels of testosterone or prolactin. This appeared not to be the case and therefore left the researchers without much of an answer as to why the fenugreek had such a pronounced effect among the men who consumed it during the study.
Should You Use Fenugreek to Boost Sex Drive?
Fenugreek is widely available and relatively inexpensive ($15-$20 for a 30-day supply of 300 mg capsules) in retail and online dietary supplement stores, including the brand used in this study, Testofen.
The only adverse health effect noted by the study research team was upset stomach reported by three of the 27 men receiving fenugreek. In all three cases, the men reported having taken the herbal extract on an empty stomach. Therefore, if you decide to try fenugreek, it would be wise to consume it with a meal.
It should also be noted that the men in the study were considered healthy adults (other than being overweight). Those with specific health conditions (diabetes, heart disease, hormone deficiencies, erectile dysfunction, etc.) were excluded from the study, and so the effect of fenugreek on libido in these populations is unknown.
That said, it seems clear that for the men who received fenugreek in the study there were pronounced and welcome improvements to their sexual desire, arousal and performance. In addition, 82% of the men taking the fenugreek also reported higher levels of general energy.
Whether the latter effect was a direct result of fenugreek or from increased sexual activity was not described.
But we’re guessing the men in the study don’t really care!
 Steels E., et al. Physiological Aspects of Male Libido Enhanced by Standardized Trigonella foenum-graceum Extract and Mineral Formulation. Phytotherapy Research. 2011 Feb 10. doi: 10.1002/ptr.3360 pub ahead of print.