Aphrodisiac and clinically proven natural performance enhancer, the ancients used tribulus terrestris to increase sexual desire and function. Turns out they were on to something – a 2008 study published in Phytomedicine found that tribulus terrestris increased mounting, and ejaculations in male rats over eight weeks.

Tribulus terrestris reduced time between ejaculations too, with several follow-up studies showing similar results.

Evidence suggests a compound in tribulus terrestris, called protodioscin, may be of further benefit to male sexual function.

Sources: Phytomedicine., 2008 Jan;15(1-2):44-54. Life Sci., 2002 Aug 9;71(12):1385-96.

A plant and member of the nightshade family, withania somnifera is used extensively in Ayurvedic medicine to promote relaxation and as a mood stabilizer. But it's more than just a natural chill pill; a 2003 review by Italian researchers found that withania somnifera increased nitric oxide synthase in macrophages. Meaning? Increased blood flow to your penis.

Studies indicate withania somnifera has a positive influence on the endocrine, cardiopulmonary and central nervous systems.

Sources: Phytomedicine., 2000 Dec;7(6):463-9. Altern Med Rev., 2000 Aug;5(4):334-46. Life Sci., 2003 Feb 21;72(14):1617-25.

17th century English herbalist Nicholas Culpepper wrote "asparagus stirs up lust in men and women." You bet it does - asparagus is an excellent source of orgasm-friendly potassium, fiber, vitamins B6, A and C, thiamine and folic acid. Asparagus adscendens also has anti-stress properties and an inhibitory effect on proinflammatory cytokines.

Also called asparagus racemosus, asparagus adscendens is rich in antioxidants and is believed to mimic the effects of testosterone. Studies on rats show increased frequency of mounting and erection quality. In the ProSolution Plus formula, it also improved ejaculation control and helped men achieve more regular and powerful orgasms.

Researchers believe asparagus adscendens may have a wide variety of other health applications, too.

Sources: Phytother Res. 2000 Dec;7(6):463-9. Asian Pac J Trop Dis. 2000 Aug;5(4):334-46.

You'll be mating a lot with mucuna pruriens. The tropical legume contains L-Dopa – a precursor to the neurotransmitter l-dopamine, an important chemical that regulates sexuality, mood and feelings of pleasure. Animal studies confirm this, with increases in erections, mounting and less time between sexual encounters.

Just as encouraging, a 2012 study published in the Journal of Sexual Medicine found that mucuna pruriens may improve libido and testosterone levels in the diabetic.

Sources: J Ethnopharmacol. 2009 Apr 21;122(3):497-501. doi: 10.1016/j.jep.2009.01.032. Epub 2009 Jan 31. J Sex Med. 2012 Dec;9(12):3066-78. doi: 10.1111/j.1743-6109.2010.01831.x. Epub 2010 Apr 26.

A highly prized plant in the Ayurvedic tradition, studies show asteracantha longifolia increased mount frequency, sperm volume and 'enhanced' attractibility toward females, along with higher fructose levels in the seminal vesicles – the tubular glands that secrete ejaculate.

Asteracantha may have other uses too. It's currently being studied as a natural treatment for iron deficiency, liver damage and several blood diseases.

Sources: Nat Prod Res. 2011 Sep;25(15):1423-31. doi: 10.1080/14786410802588493. Epub 2011 Jul 8 J Ethnopharmacol. 2010 May 27;129(2):280-2. doi: 10.1016/j.jep.2010.03.015. Epub 2010 Mar 27.

A 2007 study published in Filoterapia reveals the rhizomes of curculigo orchioides increased penile erection, mating performance and mount frequency. Erection quality improved as well, accompanied with increased attraction to female sexual partners.

Like asteracantha longifolia, we've barely scratched the surface with this flowering plant species and the medicinal properties it may hold. Current evidence suggests it may have many other health applications for common ailments linked to lower sex drive and performance.

Sources: Fitoterapia, 2007 Dec;78(7-8):530-4. Epub 2007 Jul 3. Journal of Chinese Integrated Medicine, July 2010, Vol.8, No.7

Asphaltum is an organic wax that forms between rock cracks in the Himalayas. With such dramatic origins, it's no surprise that asphaltum reportedly has more than 85 vitamins and minerals, with medicinal properties that nourish the body.

All those nutrients mean good things for your sex drive. It's used extensively in Ayurvedic medicine to increase vitality, sexual health and is believed to help spermatogenesis.

Asphaltum also possesses 'health enhancing' properties, illustrated in 2010 when researchers found it reduced fatigue at high altitudes.

Sources: J Ethnopharmacol. 2006 Oct 11;107(3):349-53. Epub 2006 Apr 18. Int J Ayurveda Res. 2010 Jan;1(1):37-40. doi: 10.4103/0974-7788.59942.