Here is all the articles that i can find at pubmed.....
Actions on Erectile Function and Libido:
Rowland, D. L., et al. “A review of plant-derived and herbal approaches to the treatment of sexual dysfunctions.” J. Sex. Marital Ther. 2003 May-Jun; 29(3): 185-205.
Waynberg, J., et al. ”Effects of Herbal vX on libido and sexual activity in premenopausal and postmenopausal women.” Adv. Ther. 2000 Sep-Oct; 17(5): 255-62.
Waynberg, J. “Male sexual asthenia—interest in a traditional plant-derived medication.” Ethnopharmacology; 1995.
Waynberg, J. “Contributions to the clinical validation of the traditional use of Ptychopetalum guyanna.” Presented at the First International Congress on Ethnopharmacology, Strasbourg, France, June 5-9, 1990.
Gaebler, H. “Revival of the drug Muira puama.” Deut. Apoth. 1979; 22(3): 94–6.
Anti-Anxiety & Nervine Actions:
da Silva, A. L., et al. “Anxiogenic properties of Ptychopetalum olacoides Benth. (Marapuama).” Phytother. Res. 2002; 16(3): 223-6.
Siqueira, I. R., et al. “Psychopharamcological properties of Ptychopetalum olachoides Bentham (Olacaceae).” Pharmaceutical Biol. 1998; 36(5): 327–34.
Hypotensive Actions:
Raymond-Hamet, A. “Physiological action of the extract of muira puama.” Comp. Rend. Soc. Biol. 1932; 109: 1064-7
Olofsson, Eric. “Action of extract of Liriosma ovata on the blood pressure, vessels and respiration of the rabbit.” Compt. Rend. Soc. Biol. 1927; 97: 1639-40.
Anti-fatigue, Tonic, & Adaptogenic Actions:
Bucci, L. R., et al. ”Selected herbals and human exercise performance.” Am. J. Clin. Nutr. 2000 Aug; 72(2 Suppl): 624S-36S.
Paiva, L., et al. “Effects of Ptychocepalum olacoides extract on mouse behaviour in forced swimming and open field tests.” Phytother. Res. 1998; 12(4): 294–96.
Waynberg, J. “Male sexual asthenia—interest in a traditional plant-derived medication.” Ethnopharmacology; 1995.
Hanawa, M., et al. “Composition containing an extract from muira puama root and plant worm extract.” Taisho Pharmacuetical Co., Ltd., Tokyo, United States Patent No. 6024984, 2000.
Siqueira, I. R., et al. “Psychopharamcological properties of Ptychopetalum olachoides Bentham (Olacaceae).” Pharmaceutical Biol. 1998; 36(5): 327–34.
Memory Enhancement & Neuroprotective Actions:
da Silva, A. L., et al. “Memory retrieval improvement by Ptychopetalum olacoides in young and aging mice.” J. Ethnopharmacol. 2004 Dec; 95(2-3): 199-203.
Siqueira, I. R., et al. “Neuroprotective effects of Ptychopetalum olacoides Bentham (Olacaceae) on oxygen and glucose deprivation induced damage in rat hippocampal slices.” Life Sci. 2004 Aug; 75(15): 1897-906.
Siqueira, I. R., et al. “Ptychopetalum olacoides, a traditional Amazonian "nerve tonic," possesses anticholinesterase activity.” Pharmacol. Biochem. Behav. 2003 Jun; 75(3): 645-50.
Siqueira, I. R., et al. “Psychopharamcological properties of Ptychopetalum olachoides Bentham (Olacaceae).” Pharmaceutical Biol. 1998; 36(5): 327–34.
Forgacs, P., et al. “Phytochemical and biological activity studies on 18 plants from French Guyana.” Plant Med. Phytother. 1983; 17(1): 22–32.
Dias Da Silva, Rodolpho. “Medicinal plants of Brazil. Botanical and pharmacognostic studies. Muira puama.” Rev. Bras. Med. Pharm. 1925; 1(1): 37–41.
Anti-cholesterol Actions:
Jayasuriya, H., et al. “Diterpenoid, steroid, and triterpenoid agonists of liver X receptors from diversified terrestrial plants and marine sources.” J. Nat. Prod. 2005; 68(8): 1247-52.
Cherksey, B. D. “Method of preparing Muira puama extract and its use for decreasing body fat percentage and increasing lean muscle mass.” United States Patent No. 5516516, 1996.
The last article under Anti-cholesterol Actions mentions increasing muscle mass in the title of the article, but it is a patent. I cannot find this article however. Most of this evidence of its mechanism of action is anectodal and hyped up by Usp labs. I experienced nothing from powerfull, not even increased sleep.