for educational and safety purposes
Libido and sexual-function compounds; PDE5 inhibitors, melanocortin peptides, and hormonal modulators.
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Dapoxetine (marketed as Priligy) is a fast-acting selective serotonin reuptake inhibitor developed specifically as the first on-demand medication for premature ejaculation [1]. In large Phase III trials it roughly tripled the time to ejaculation and improved control and satisfaction, working from the very first dose and clearing the body quickly to suit as-needed use [1][2]. Approved across Europe and much of Asia, dapoxetine is the best-evidenced pharmaceutical option for premature ejaculation available today.
Acetildenafil, also known as hongdenafil, is a designer analogue of sildenafil (Viagra) and one of the prototype sildenafil-like PDE5 inhibitors that surfaced in all-natural male-enhancement supplements. Built to mimic sildenafil's blood-flow-boosting mechanism, it delivers erectile-support effects without the branding of a prescription drug, which made it one of the earliest and most widely copied research analogues in the space. It is sought out in gray-market circles precisely for reproducing a pharmaceutical effect in an unregulated form.
N-Ethyl Tadalafil is a designer analog of tadalafil, the long-acting PDE5 inhibitor behind Cialis, built by modifying the original molecule. It is presumed to share tadalafil's ability to relax blood vessels and support erections, and it turns up most often as an undeclared ingredient in sexual-enhancement supplements. Because the analog itself has not been formally tested, it is best understood through the well-established pharmacology of its parent drug rather than through direct evidence.
N-Isopropyl Tadalafil is a designer analog of tadalafil, the long-acting PDE5 inhibitor sold as Cialis, differing only by a small change to one part of the molecule. Like its parent, it is presumed to relax blood vessels and enhance erections, and it has been identified as an undeclared ingredient hidden inside sexual-performance supplements. Since the analog has never been formally tested, its profile is inferred from tadalafil rather than from any dedicated clinical evidence.
Arginine, or L-arginine, is a conditionally essential amino acid that the body uses to build proteins and, importantly, as the raw material for making nitric oxide, a molecule that relaxes and widens blood vessels. It also plays central roles in the urea cycle that clears ammonia and in the production of creatine. Healthy adults usually make enough arginine, but needs can rise during growth, illness, or injury; it is obtained from protein-rich foods and taken as a supplement for cardiovascular and exercise-related purposes.
Citrulline is a non-proteinogenic alpha-amino acid named after the watermelon, from which it was first isolated. In the body it is a key intermediate in the urea cycle and a precursor to the amino acid arginine, which is in turn used to make nitric oxide. It is sold as a dietary supplement, often marketed for blood flow and exercise performance, though the evidence for those uses is mixed.
D-aspartic acid is the D-enantiomer of aspartic acid and one of the few D-amino acids found naturally in mammals, concentrating in neuroendocrine tissues such as the brain, pituitary, and testes. Mechanistic work indicates that it participates in the release and synthesis of luteinizing hormone and testosterone, acting in the pituitary through cyclic GMP and in testicular Leydig cells by upregulating the steroidogenic acute regulatory (StAR) protein and modulating luteinizing hormone receptor trafficking, in concert with NMDA-receptor-mediated stimulation of gonadotropin-releasing hormone. Despite this plausible endocrine role, controlled human trials tell a more sobering story; supplementation in resistance-trained men generally failed to raise testosterone, and a higher 6 g daily dose actually lowered total and free testosterone. It is therefore best characterized as a physiologically active amino acid whose marketed ergogenic and testosterone-boosting claims are not supported in trained populations.
Dehydroepiandrosterone (DHEA) is an endogenous androstane neurosteroid and the most abundant circulating steroid hormone in humans, secreted chiefly by the adrenal cortex and also synthesized de novo within the central nervous system. It functions primarily as a precursor to androgens and estrogens, yet exerts direct actions on the brain by acting as an agonist at the sigma-1 receptor (an endoplasmic reticulum chaperone protein that shapes calcium and neurotrophic signaling), as a positive modulator of NMDA receptor (the principal excitatory glutamate ion channel involved in learning) signaling, and, chiefly as its sulfate ester DHEAS, as a negative allosteric modulator of the GABA-A receptor (the brain's main inhibitory ion channel). DHEA additionally behaves as a functional anti-glucocorticoid, buffering the neurotoxic effects of cortisol, and shows neuroprotective and mood-related activity in preclinical and clinical studies. Circulating concentrations peak in early adulthood and decline markedly with age, a phenomenon termed adrenopause that has driven its widespread use as an over-the-counter supplement.
Fadogia agrestis is a shrub in the coffee family (Rubiaceae) native to West Africa, where its stem has a traditional reputation as an aphrodisiac. It has become popular as a dietary supplement marketed for raising testosterone and libido. The evidence behind those claims comes almost entirely from animal studies, and its safety in humans has not been established.
Fenugreek (Trigonella foenum-graecum) is an annual legume whose aromatic seeds and leaves are used worldwide as a spice and in traditional medicine. Its seeds, which carry a maple-like aroma, are taken as a dietary supplement marketed for blood sugar, cholesterol, testosterone and milk production in nursing mothers. High-quality clinical evidence for most of these uses is still limited.
Gonadorelin is a synthetic copy of GnRH, the master hypothalamic signal that tells the pituitary to release LH and FSH, and it carries a real clinical pedigree as an FDA-recognized tool for assessing the pituitary-gonadal axis and inducing ovulation. Delivered in pulses that mimic the body's natural rhythm, it wakes the whole reproductive axis and keeps endogenous hormone production humming, which is exactly why it is valued for preserving testicular function. For working with the body's own hormonal machinery rather than around it, gonadorelin is a smart, physiology-friendly choice.
GPL Man is a capsule combining six animal organ peptide extracts with alpha lipoic acid, sold as a men's anti ageing formula; the peptide portion is undefined extract rather than sequenced peptide.
HCG (human chorionic gonadotropin) is a gonadotropin hormone that acts as a direct luteinizing hormone mimic, binding LH receptors on testicular Leydig cells to switch on the body's own testosterone and sperm production [1][2]. Because it drives the testes at the source, it is a cornerstone tool for preserving fertility and testicular function in men on hormone therapy and for restarting a suppressed axis [2][3]. Clinicians favor it precisely because it raises endogenous testosterone without the fertility penalty seen with testosterone replacement alone [2].
HMG (human menopausal gonadotropin, or menotropin) is a purified gonadotropin preparation that delivers both FSH and LH activity in a single agent, making it a workhorse of fertility medicine [1]. In women it drives controlled ovarian stimulation for IVF, matching recombinant FSH on live birth rates while adding the LH activity that recombinant FSH lacks [1][2]. In men with hypogonadotropic hypogonadism, HMG paired with hCG restores testosterone and induces spermatogenesis, giving previously infertile patients a genuine path to fatherhood [4][6].
Kisspeptin is a reproductive neuropeptide that sits at the very top of the hormonal axis controlling fertility, acting as the master switch that tells the brain to release gonadotropin-releasing hormone (GnRH) [1]. Discovered first as a cancer metastasis suppressor and later found to be essential for puberty, it has emerged as a versatile clinical tool: administered to people, kisspeptin enhances sexual and emotional brain processing, shows promise for low sexual desire, and can safely trigger egg maturation in IVF [1][2][5][6]. Its dual role in both the reproductive hormone cascade and the limbic brain makes it one of the most intriguing peptides in modern endocrinology [2][4].
Libidon is a capsule of peptide fractions extracted from animal prostate gland, sold as a supplement for prostate health; it is an organ extract and not a defined peptide.
Lovelas Forte is a Russian herbal capsule blend sold for erectile function and libido.
Maca (Lepidium meyenii) is an edible plant of the mustard family, Brassicaceae, native to the high Andes of Peru. Its starchy root, or hypocotyl, has been eaten and used as a traditional remedy for centuries and is now sold worldwide as a powder or extract. It is best known for claims around libido, sexual function, and energy, although the clinical evidence is modest and mixed.
Papaverine is an opium poppy alkaloid with no opioid activity, used as a smooth muscle relaxant for vascular and visceral spasm and, injected into the penis, for erectile dysfunction.
Peptide Complex Pro 06 is a leave on skin lotion combining four animal organ peptide extracts with a ginseng derived antioxidant complex and cinnamon oil, sold for the male reproductive system; it is a topical mixture rather than a peptide of known sequence.
Peptide Complex Pro 07 is a leave on skin lotion combining vascular, brain and thymus peptide extracts with a ginseng derived antioxidant complex and sandalwood oil, sold for the female reproductive system; it is a topical mixture rather than a peptide of known sequence.
Prostalamin is an oral prostate tissue extract sold as a food supplement for prostatitis, urinary symptoms and erectile function, none of which it has been shown to change in a controlled trial.
Prostamax is marketed as a synthetic prostate peptide bioregulator, part of the Russian family of short, tissue-targeted peptides developed from the concept that organ-specific peptide extracts can normalize function in the corresponding tissue. The compound itself has essentially no dedicated peer-reviewed literature; the supporting evidence is class-level and centers on the related natural prostate peptide preparation Prostatilen, which has been used in Russian urology for chronic abacterial prostatitis, with reported improvements in urinary symptoms, prostate secretion parameters, and erectile function measured by penile Doppler ultrasonography. These studies are small, largely open-label or single-center, and published chiefly in Russian-language journals, so claims specific to Prostamax should be regarded as preliminary and extrapolated from the broader peptide-bioregulator class rather than established for the product by name.
PT-141 (bremelanotide) is a first-in-class libido peptide that works in the brain rather than the bloodstream, activating melanocortin pathways to spark sexual desire and arousal in both women and men [1][2]. Unlike erectile-focused drugs that act on blood vessels, it targets the central circuits of desire, and it is the active ingredient in Vyleesi, approved by the FDA in 2019 for hypoactive sexual desire disorder in premenopausal women [2][3]. A synthetic analog of the hormone alpha-MSH, PT-141 is prized as the rare desire-boosting agent backed by large randomized clinical trials [3][4].
RAD-150 (TLB-150 Benzoate) is a research chemical marketed as an ester form of the popular SARM RAD-140 (Testolone), promoted for building muscle and strength with a potentially longer-acting profile [1]. Like other selective androgen receptor modulators, it is intended to stimulate the androgen receptor in muscle and bone, but RAD-150 itself has no published pharmacological or clinical studies, so its profile is inferred from RAD-140 and the broader SARM class [1]. It is an unapproved, WADA-banned research chemical, and the RAD-140 family it is based on has been linked in case reports to serious cardiovascular harm [1][2][3].
Revilab SL 09 is a sublingual drop combining pineal, testis, bladder and prostate peptide extracts with herbal extracts and essential oils, sold for men's health; it is a proprietary mixture rather than a peptide of known sequence.
S-23 is a high-affinity, orally active selective androgen receptor modulator (SARM) first characterized as a candidate for hormonal male contraception. It binds the androgen receptor as a full agonist and, in animal studies, builds lean muscle mass and bone mineral density while cutting fat, a tissue-selective anabolic profile that has drawn strong interest for body recomposition. It also potently and reversibly suppresses testosterone and sperm production, which is central to both its contraceptive rationale and its cautions.
Samprost is a freeze-dried extract of bull calf prostate, reconstituted and injected in Russia for chronic prostatitis.
Shilajit is a blackish-brown, tar-like exudate that seeps from rocks in high mountain ranges and is composed largely of humic substances such as fulvic acid together with minerals and trace elements. It has been used for centuries in Ayurvedic and other traditional systems as a general tonic. Modern evidence for its health effects is limited, and product quality varies, with heavy-metal contamination a recognized concern.
Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor best known for treating erectile dysfunction, for which it was the first approved oral drug. Under a separate brand it is also used to treat pulmonary arterial hypertension. Discovered by Pfizer and approved in 1998, it is sold most famously as Viagra and, for lung disease, as Revatio.
Spermstrong is a Russian capsule blend of amino acids, antioxidant vitamins and trace minerals sold to improve sperm count and motility.
Testalamin is a testicular tissue extract sold as a food supplement for sperm production and erectile function, and no semen analysis or hormone data have ever been published for it.
Testogenon is a Russian herbal and amino acid capsule sold on the claim that it raises the body's own testosterone.
Testoluten is a capsule of peptide fractions extracted from animal testes, sold as a supplement for male reproductive function; it is an organ extract and not a defined peptide.
Testosterone undecanoate is a long-chain fatty acid ester of testosterone taken as an oral softgel; it is absorbed through intestinal lymphatics rather than the portal vein, which is what lets an oral androgen work at all.
Tongkat ali is the common name for Eurycoma longifolia, a flowering shrub of the family Simaroubaceae native to Southeast Asia, whose roots are used in traditional medicine and sold as a dietary supplement [1]. It is widely marketed for claims about testosterone, male fertility, libido, and physical performance, though the supporting clinical evidence is mixed and largely preliminary [1][3]. The plant contains a range of bioactive compounds known as quassinoids, including eurycomanone.
Yohimbine is an indole alkaloid obtained mainly from the bark of the West African tree Pausinystalia johimbe (yohimbe). Pharmacologically it acts chiefly as an antagonist of alpha-2 adrenergic receptors, and it has a long history as a purported aphrodisiac and a treatment for erectile dysfunction. It is available in some countries as a prescription drug and elsewhere as a dietary supplement, though its stimulant-like cardiovascular effects and inconsistent product quality have raised safety concerns.
Zhenoluten is a capsule of peptide fractions extracted from animal ovaries, sold as a supplement for female reproductive function and the menopausal transition; it is an organ extract and not a defined peptide.
Alprostadil is a manufactured form of prostaglandin E1 (PGE1), a naturally occurring signaling lipid, used as a vasodilator and smooth muscle relaxant. Its best-known applications are the treatment of erectile dysfunction, where it is delivered directly into the penis, and the emergency care of certain newborns with congenital heart defects, in whom it keeps a fetal blood vessel open until surgery. It is also used in some countries for severe peripheral arterial disease [1][2].
Avanafil is a phosphodiesterase type 5 (PDE5) inhibitor used to treat erectile dysfunction, sold under the brand names Stendra and Spedra. It is notable for its fast onset, being absorbed within roughly thirty to forty-five minutes, and for its high selectivity for the PDE5 enzyme. Invented at Mitsubishi Tanabe Pharma and approved by the US Food and Drug Administration in 2012, it works by boosting the nitric-oxide signaling that relaxes blood vessels in the penis.
Avanafil + Dapoxetine is a fixed-dose combination that pairs avanafil, a fast-acting PDE5 inhibitor for erectile dysfunction, with dapoxetine, a short-acting selective serotonin reuptake inhibitor used to delay ejaculation. It is marketed in some countries as an on-demand treatment for men who have both erectile dysfunction and premature ejaculation. Each ingredient is well studied on its own, but the combination product itself has little dedicated clinical trial data.
Flibanserin is a serotonergic medication approved to treat hypoactive sexual desire disorder (HSDD) in premenopausal women, sold under the brand name Addyi. It was first developed as an antidepressant but was repurposed after it appeared to influence sexual desire. Unlike drugs for erectile dysfunction, it is taken daily and acts on the brain rather than on blood flow. Its 2015 approval by the United States Food and Drug Administration was controversial, following two earlier rejections and a debate over whether its modest benefits justified its risks.
Lidocaine is a local anesthetic of the amide type and also a class Ib antiarrhythmic drug. It works by blocking the voltage-gated sodium channels that nerves use to fire, producing numbness where it is applied or injected. First made in the 1940s and sold under the brand name Xylocaine, it is one of the most widely used numbing agents in medicine and dentistry and appears on the World Health Organization's List of Essential Medicines.
Progesterone (P4; pregn-4-ene-3,20-dione) is an endogenous pregnane steroid hormone best known for its reproductive roles and is the prototypical neuroactive precursor within the neurosteroid system. Although the parent hormone signals principally through classical nuclear progesterone receptors and through membrane-associated receptors such as PGRMC1 and the mPR/PAQR family, most of its rapid effects on neuronal excitability arise only after sequential metabolism to 5-alpha-dihydroprogesterone and then to allopregnanolone, one of the most potent endogenous positive allosteric modulators of the GABA-A receptor (the brain's principal inhibitory chloride channel). Progesterone and its metabolites are synthesized within the nervous system itself, where they regulate myelination, neuronal survival, neuroinflammation, and inhibitory tone. It has been studied extensively as a neuroprotective agent, with strong preclinical support but negative large-scale human trials in acute traumatic brain injury.
Sildenafil plus dapoxetine is a pairing of two oral drugs used together in men who have both erectile dysfunction and premature ejaculation. Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor that improves erectile function, while dapoxetine is a short-acting selective serotonin reuptake inhibitor (SSRI) developed specifically to delay ejaculation. The pairing targets the two most common male sexual complaints at once, and fixed-dose tablets combining them are marketed in some countries.
Sildenafil plus duloxetine refers to the combined use of a phosphodiesterase type 5 (PDE5) inhibitor and a serotonin-norepinephrine reuptake inhibitor (SNRI) in men who have both erectile dysfunction and premature ejaculation. Sildenafil improves erectile function, while duloxetine, primarily an antidepressant and pain medication, has been studied off-label for its ability to delay ejaculation. The pairing follows a broader strategy of combining a reuptake inhibitor with a PDE5 inhibitor to treat both problems together.
Sildenafil plus fluoxetine is the combined use of a phosphodiesterase type 5 (PDE5) inhibitor and a selective serotonin reuptake inhibitor (SSRI) in men with both erectile dysfunction and premature ejaculation. Sildenafil improves erectile function, while fluoxetine, a long-acting SSRI antidepressant, delays ejaculation as a side effect that is used off-label for premature ejaculation. Studies suggest the pairing can outperform either agent alone in appropriately selected men.
Sildenafil plus tadalafil is the combined use of two phosphodiesterase type 5 (PDE5) inhibitors for erectile dysfunction, typically a longer-acting daily tadalafil together with on-demand sildenafil. The strategy is generally reserved for men who respond poorly to a single PDE5 inhibitor. Because both drugs share the same basic mechanism, combining them mainly extends coverage rather than adding a new mode of action.
Tadalafil plus dapoxetine is a fixed-dose combination that pairs two medicines with complementary effects on male sexual function. Tadalafil is a long-acting PDE5 inhibitor that improves erections, while dapoxetine is a short-acting selective serotonin reuptake inhibitor used to delay ejaculation. Marketed under names such as Tadapox, the combination is aimed at men who have both erectile dysfunction and premature ejaculation and is taken on demand before sexual activity.
Udenafil is a phosphodiesterase type 5 (PDE5) inhibitor, a class of drug used mainly to treat erectile dysfunction. Marketed under the brand name Zydena, it was developed by the South Korean company Dong-A Pharmaceutical and is approved in Korea and several other countries, though not in the United States. It is distinguished by a relatively quick onset together with a long duration of action, which allows both on-demand and once-daily use [1].
Vardenafil is a prescription medication of the phosphodiesterase type 5 (PDE5) inhibitor class, used to treat erectile dysfunction. Marketed under brand names such as Levitra and the orally disintegrating Staxyn, it improves the ability to achieve and maintain an erection by enhancing the body's natural response to sexual stimulation. It belongs to the same drug family as sildenafil and tadalafil and is taken on demand before sexual activity.
Vardenafil plus dapoxetine is a combination of two drugs used together to treat men who have both erectile dysfunction and premature ejaculation. Vardenafil is a phosphodiesterase type 5 (PDE5) inhibitor that improves erections, while dapoxetine is a short-acting selective serotonin reuptake inhibitor (SSRI) that delays ejaculation. The pairing is taken on demand before sexual activity and is marketed as a fixed-dose combination in some countries.
MT-2 (Melanotan II) is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone that acts as a non-selective agonist at melanocortin receptors, most notably MC1R and MC4R. Through MC1R activation it stimulates melanogenesis, producing durable skin darkening with reduced ultraviolet exposure, while central MC4R activation drives pro-erectile and pro-sexual effects that were demonstrated in early human trials of erectile dysfunction and later informed development of the approved drug bremelanotide. Preclinical work has additionally characterized its capacity to suppress food intake, reduce adiposity and improve insulin sensitivity, promote peripheral nerve regeneration and neuroprotection, and stimulate central oxytocin pathways; the last of these underlies reports of rescued social behavior in a rodent model of autism. MT-2 remains an unapproved research compound, and its unregulated recreational use has been linked to adverse events including nausea, rhabdomyolysis, renal injury and case reports of melanoma arising in heavily pigmented skin.
Tadalafil is a long-acting phosphodiesterase type 5 (PDE5) inhibitor, a class of drugs that relax certain blood vessels. Sold under brand names such as Cialis and Adcirca, it is used to treat erectile dysfunction, the urinary symptoms of an enlarged prostate, and pulmonary arterial hypertension. It is distinguished from related drugs by its notably long duration of action.
3α-Androstanediol (5α-androstane-3α,17β-diol) is an endogenous neurosteroid formed as the terminal 3α-reduced metabolite of dihydrotestosterone (DHT, the most potent natural androgen). Despite its androgenic origin it binds the androgen receptor only weakly; its defining pharmacology is potent positive allosteric modulation of the GABA-A receptor (the brain's principal inhibitory chloride ion channel), which produces anxiolytic (anxiety-reducing) and anticonvulsant (seizure-suppressing) effects in animal models. It is widely regarded as the androgenic counterpart of allopregnanolone (the analogous progesterone-derived neurosteroid), and is proposed to mediate much of the influence that testosterone exerts on seizure threshold, anxiety, and mood in males. It additionally acts as a ligand of estrogen receptor beta (ERβ), which may underlie some of its cognitive and neuroprotective actions.
5α-Dihydroprogesterone (5α-DHP) is an endogenous neurosteroid and progestogen formed when the enzyme 5α-reductase reduces progesterone at the A-ring of the steroid nucleus, yielding 5α-pregnane-3,20-dione. It occupies the committed first step of the principal neurosteroid pathway, standing between progesterone and allopregnanolone (its 3α-hydroxylated metabolite and one of the most potent naturally occurring positive modulators of the GABA-A receptor, the brain's main inhibitory ion channel). Unlike allopregnanolone, 5α-DHP is itself a high-affinity agonist of the classical (nuclear) progesterone receptor, driving progesterone-responsive gene transcription; in horses it is a fully biopotent progesterone receptor agonist that sustains the second half of pregnancy after circulating progesterone becomes undetectable. It is synthesized in situ within neurons and glia of the central and peripheral nervous systems, where its production rises after nerve injury and falls under chronic stress.
Androstadienol (androsta-5,16-dien-3β-ol) is an endogenous C19 (nineteen-carbon) delta-5,16 steroid alcohol that functions as the committed biosynthetic precursor of the 16-androstene family of chemosensory steroids, including androstadienone, androstenone and androstenol. It is formed in the gonads (and, at lower levels, in other steroidogenic tissue) from pregnenolone by a minor side activity of the enzyme CYP17A1 (cytochrome P450 17A1, the same enzyme that makes dehydroepiandrosterone); this activity is historically called andien-beta synthase or 16-ene-synthase. Because its downstream metabolites are the putative human axillary chemosignals and the compounds responsible for boar taint, androstadienol occupies the upstream branch point of a pathway of considerable interest to olfactory neuroscience and reproductive endocrinology. It should not be confused with fasedienol (aloradine), a synthetic 4,16-dien-3β-ol nasal drug; androstadienol is the naturally occurring 5,16-diene.
Androstadienone (androsta-4,16-dien-3-one) is an endogenous volatile C19 16-androstene steroid found in male axillary sweat, semen, saliva and plasma, and the most intensively studied candidate human chemosignal or "pheromone." It is not a classical ion-channel neurosteroid; its central actions are triggered peripherally through the main olfactory epithelium, where the odorant receptor OR7D4 (a G-protein-coupled receptor) is the principal transducer and its genetic variation explains much of the wide person-to-person difference in whether the compound smells sweaty, urinous, sweet or nothing at all. Controlled exposure has been reported to modulate mood, sustained attention, salivary cortisol, autonomic tone and hypothalamic and frontolimbic activity, often in a sex-dependent and strongly context-dependent way. The evidence base is large but contested; effect sizes are small and several findings have failed to replicate, so the compound remains a putative rather than a proven pheromone.
Androstenol (5-alpha-androst-16-en-3-alpha-ol, with a 3-beta epimer) is an endogenous 16-androstene steroid (a C19 steroid that lacks the C-17 oxygen of typical androgens) and a putative human chemosignal. It is synthesized alongside testosterone in the testis, secreted in axillary (underarm) sweat, and also occurs as a major aroma component of truffles, where its volatile, musky odor is biologically active. Its documented neuroactivity in humans is chemosensory; smelling androstenol has been reported to shift self-rated mood and social judgments in some experiments and to activate the anterior hypothalamus in women, although rigorous reviews consider the evidence for a true human pheromone effect weak and inconsistent. It is grouped with the neurosteroids because it is a steroid with measurable central chemosensory and neuroendocrine effects, not because a defined ion-channel mechanism has been established.
Androstenone (5alpha-androst-16-en-3-one) is an endogenous 16-androstene steroid and the archetypal mammalian putative pheromone, best known as the principal component of "boar taint" (the urinous off-odor of intact male pork) and as a minor constituent of human axillary sweat and saliva. Unlike the classic anesthetic neurosteroids that act on the GABA-A receptor (the brain's main inhibitory ion channel), androstenone is a chemosensory neuroactive steroid; its dominant known target in the nervous system is the olfactory receptor OR7D4, expressed on sensory neurons of the nasal epithelium. Its perception is one of the most strikingly variable in human sensory biology, ranging from a strong urinous or sweaty odor, to a faint sweet or floral note, to complete inability to detect it, and this variation is largely explained by coding polymorphisms in the OR7D4 gene. The compound is a foundational model odorant for the molecular genetics of smell, for specific anosmia, and for olfactory plasticity.
Beta-sitosterol is a phytosterol, a plant-derived sterol whose chemical structure closely resembles that of cholesterol. It is one of the most abundant plant sterols in the human diet and is distributed widely in vegetable oils, nuts, seeds, legumes, and other plant foods. It has been studied mainly for two purposes: lowering blood cholesterol by interfering with cholesterol absorption in the gut, and easing the urinary symptoms of benign prostatic hyperplasia [1][2]. It is available as a dietary supplement and as an added ingredient in cholesterol-lowering foods.
Catuaba is a common name for the bark of several Brazilian trees, most often Trichilia catigua and Erythroxylum vaccinifolium, used in folk medicine as an aphrodisiac and general tonic. Prepared traditionally as a bark infusion, it is taken for fatigue, low libido, and nervousness, and is sold internationally as a dietary supplement. Preclinical studies, chiefly on Trichilia catigua, report antidepressant-like, antioxidant, and neuroprotective effects, but there is little clinical evidence in humans, and products vary widely because the name covers more than one plant.
Cistanche is a genus of parasitic desert plants in the family Orobanchaceae whose dried fleshy stems have long been used in traditional Chinese medicine. Known in Chinese as rou cong rong and nicknamed desert ginseng, it is taken as a tonic said to support vitality, sexual function, and healthy aging. Its most studied constituents are phenylethanoid glycosides such as echinacoside and acteoside, though most of the supporting evidence to date comes from laboratory and animal research.
Estratetraenol (estra-1,3,5(10),16-tetraen-3-ol) is an endogenous estrane steroid (a C18 steroid built on the same carbon skeleton as the estrogens) first isolated from the urine of pregnant women in 1968. It carries an aromatic A-ring like the classical estrogens but lacks the oxygen at carbon 17, which leaves it essentially devoid of conventional estrogenic hormone activity. It is best known as a putative human chemosignal (a chemical thought to carry social information between individuals), where it is treated as the female-associated counterpart to the male-associated steroid androstadienone. A body of psychophysical and neuroimaging work reports that trace, near-odorless exposure to estratetraenol can bias perception, mood, and physiological arousal in a sexually dimorphic manner, although independent replications have been mixed and its status as a true pheromone remains contested.
Horny goat weed is the common name for Epimedium, a genus of flowering plants in the barberry family, Berberidaceae, most species of which are native to China. Known in Chinese medicine as yin yang huo, it has been used for centuries as a tonic and reputed aphrodisiac, as well as for fatigue and bone and joint complaints. Its principal active compound is the flavonoid icariin, which has been studied for effects on erectile function and bone.
Piceatannol is a stilbenoid, a naturally occurring plant polyphenol closely related to resveratrol, from which it differs by a single extra hydroxyl group. It is found in grapes, red wine, passion fruit seeds, and other plants, and the body can also form it from resveratrol. Studied mainly in the laboratory, it has drawn interest for antioxidant, anti-inflammatory, and anticancer activities and as an inhibitor of the enzyme Syk kinase, but it remains a research compound rather than an approved medicine.
Propionyl-L-carnitine is an acyl ester of L-carnitine, a naturally occurring quaternary ammonium compound the body uses to move fatty acids into mitochondria for energy production. It has been studied mainly as a treatment for peripheral arterial disease and the exercise-induced leg pain known as intermittent claudication, where it is thought to correct a secondary carnitine deficiency in poorly perfused muscle. The compound is sold in parts of Europe as a prescription cardiovascular agent, though it has not been approved for use in the United States.
Pycnogenol is a trademarked dietary supplement made from the bark of the French maritime pine, Pinus pinaster, standardized to a high content of procyanidins. Rich in plant polyphenols that act as antioxidants, it is marketed for a wide range of conditions from circulation problems to skin health. Independent reviews of the clinical trials, however, have concluded that the evidence is not strong enough to confirm a benefit for any specific disorder. It is sold as a supplement rather than an approved medicine.
Tribulus terrestris is a flowering plant in the caltrop family, Zygophyllaceae, widely known as puncture vine, goathead or devil's-thorn for its hard, spiny fruit. Native to warm regions of southern Eurasia and Africa and now a widespread weed, it has a long history in traditional medicine and is sold today as a dietary supplement marketed for libido, athletic performance and testosterone support. Controlled research has not consistently shown that it raises testosterone in healthy men [1].
