Your biology,
calibrated.

Bioavailable acetylcholine precursor

A highly bioavailable choline compound that crosses the blood–brain barrier and supplies substrate for acetylcholine synthesis. Studied for memory, attention, and power output in athletic contexts.

Choline and phospholipid support

Provides both choline and cytidine, supporting acetylcholine synthesis and phospholipid membrane repair. Researched for attention, memory, and recovery after ischemic insult.

Acetylcholinesterase inhibition

A plant alkaloid from Huperzia serrata that reversibly inhibits acetylcholinesterase, raising synaptic acetylcholine levels. Studied for memory consolidation and cognitive decline.

Cholinergic lipofuscin clearance

An ester of DMAE and pCPA studied for its ability to reduce lipofuscin accumulation in aging neurons while supplying cholinergic substrate. Researched primarily in the context of age-related cognitive decline.

Choline pathway intermediate

Dimethylaminoethanol, a naturally occurring choline analog studied for effects on alertness and mood. Its mechanism is debated, with proposed roles in membrane composition and cholinergic signaling.

Basic choline substrate

A simple, economical salt form of choline supporting acetylcholine synthesis and hepatic methyl-group metabolism. Less brain-penetrant than Alpha-GPC or citicoline, but foundational for dietary choline sufficiency.

Acetyl-group shuttle for neurons

An acetylated carnitine that crosses the blood–brain barrier, supporting mitochondrial fatty-acid transport and donating acetyl groups relevant to acetylcholine synthesis. Studied for mental fatigue, mood, and age-related cognitive decline.

The original pyrrolidone nootropic

The founding compound of the racetam family, studied for membrane fluidity, corpus-callosum communication, and cognition in age-related decline. Its precise mechanism remains under investigation.

AMPA modulation, anxiolytic tone

A fat-soluble racetam that positively modulates AMPA receptors and has been studied for anxiety, mood, and holistic cognitive processing in animal and limited human research.

Stimulating logical-processing racetam

A water-soluble racetam studied for attention, spatial learning, and logical processing, with a mildly stimulating character. Research centers on cholinergic and glutamatergic signaling.

High-potency choline uptake enhancer

Among the most potent classical racetams, studied for enhancing high-affinity choline uptake in the hippocampus. Researched for memory formation and cognitive recovery after brain injury.

Phenylated stimulant racetam

A phenyl-ring modification of piracetam with pronounced psychostimulant and cold-tolerance properties, developed in the Russian space program. Tolerance develops with regular use, and it appears on athletic banned-substance lists.

Choline uptake enhancement

A racetam studied for enhancing high-affinity choline uptake, the rate-limiting step of acetylcholine synthesis. Early research has explored depression with comorbid anxiety and retinal function.

Metabotropic glutamate modulation

A racetam acting on metabotropic glutamate receptors and GABA-B signaling, investigated in clinical trials for ADHD in adolescents with specific glutamatergic gene variants.

Peptide-derived racetam analog

A dipeptide analog of piracetam studied for cognition and neuroprotection, with proposed effects on NGF and BDNF expression. Widely researched in Russian clinical literature.

D2 agonism, prolactin suppression

An ergot-derived dopamine D2 agonist that lowers prolactin and has been studied for metabolic effects on glucose and lipid handling. Prescription-only, for use under physician supervision.

Dopamine agonist, serotonin antagonist

An ergoline that combines dopamine agonism with serotonin 5-HT2 antagonism, with low affinity for the 5-HT2B receptor implicated in the valvular fibrosis associated with older ergot derivatives. Studied for Parkinson's disease, hyperprolactinemia, and migraine prophylaxis. Prescription-only, for use under physician supervision.

Natural L-DOPA source

A legume extract standardized for L-DOPA, the direct precursor to dopamine. Studied for mood, motivation, prolactin modulation, and male fertility parameters.

Catecholamine precursor amino acid

The amino-acid precursor to dopamine, norepinephrine, and thyroid hormone. Studied for preserving working memory and cognitive performance under acute stress, sleep deprivation, and cold exposure.

Selective MAO-B inhibition

A selective MAO-B inhibitor that slows dopamine breakdown, studied for motivation, longevity in animal models, and neuroprotection. Prescription-only, for use under physician supervision.

Lipophilic thiamine, dopaminergic tone

A synthetic dimer of thiamine that crosses the blood–brain barrier more readily than the parent vitamin, studied for asthenia (fatigue), motivation, and memory via effects on dopaminergic and cholinergic transmission.

Endogenous trace amine

An endogenous trace amine that promotes catecholamine release, studied for transient effects on mood and focus. Rapidly degraded by MAO-B, giving it a short duration of action.

Broad serotonin and histamine antagonism

A first-generation antihistamine with broad serotonin-receptor antagonism, studied for appetite stimulation, migraine prophylaxis, and suppression of ACTH-driven cortisol output. Its sedative and anticholinergic character reflects central H1 blockade. Prescription-only, for use under physician supervision.

Ergoline serotonin antagonist

An ergoline compound combining serotonin antagonism with mild dopamine agonism and prolactin suppression. Used experimentally to probe serotonergic contributions to mood, appetite, and neuroendocrine output. Prescription-only where available, for use under physician supervision.

Peripheral H2 histamine blockade

An H2 histamine antagonist that reduces gastric acid secretion by blocking histamine signaling at the parietal cell, with a favorable interaction profile relative to earlier H2 blockers. Also researched for off-label cognitive and immune applications.

Mast-cell stabilization, antihistamine

A mast-cell stabilizer and H1 antihistamine studied for gut inflammation, allergic conditions, and mast-cell activation syndromes, where it limits the release of histamine and tryptase from degranulating mast cells. Prescription-only in oral form in many regions.

Selective 5-HT3 antagonism

A selective serotonin 5-HT3 receptor antagonist used clinically for nausea, acting on vagal afferents and the chemoreceptor trigger zone. Also researched for gut-derived serotonin's role in motility and mood. Prescription-only, for use under physician supervision.

Transient opioid-receptor blockade

Naltrexone at low intake levels transiently blocks opioid receptors, prompting a rebound in endogenous endorphin signaling. Studied for autoimmune conditions, mood, and inflammation; prescription-only, for use under physician supervision.

Alternative electron carrier

A redox-cycling dye that can act as an alternative electron carrier in the mitochondrial transport chain, studied for memory, mood, and neuroprotection. Interacts with serotonergic medications and requires pharmaceutical-grade purity.

Adenosine antagonism, metabolic stimulation

An adenosine-receptor antagonist that raises alertness and metabolic rate, studied for pro-metabolic and liver-protective effects. Extensively studied for cognition, endurance, and hepatic health.

Lipid-soluble B1 for oxidative metabolism

A lipid-soluble thiamine derivative with high tissue penetration, supporting pyruvate dehydrogenase and the oxidative disposal of glucose. Studied in thiamine-deficiency states and dysautonomia, where restoring cofactor availability shifts metabolism away from lactate accumulation.

Fatigue resistance, stress buffering

An arctic root standardized for rosavins and salidroside, studied for mental fatigue, stress resilience, and exercise performance. Proposed mechanisms include monoamine modulation and HPA-axis buffering.

Memory consolidation herb

An Ayurvedic herb standardized for bacosides, studied for memory consolidation and learning rate over multi-week timescales. Proposed mechanisms include dendritic branching and antioxidant effects in the hippocampus.

NGF-linked mushroom

A culinary mushroom (Hericium erinaceus) whose hericenones and erinacines are studied for stimulating nerve growth factor synthesis. Researched for cognition, mood, and peripheral nerve support.

Ginsenoside-driven vitality tonic

The classical Korean and Chinese ginseng, standardized for ginsenosides and studied for cognition, fatigue, glucose regulation, and erectile function. One of the most researched adaptogens in the clinical literature.

Alpha-wave relaxation without sedation

An amino acid from green tea that promotes alpha-band brain activity, studied for relaxed alertness and for smoothing the stimulant edge of caffeine. Modulates glutamate and GABA signaling.

Primary inhibitory neurotransmitter

The brain's principal inhibitory neurotransmitter, taken orally and studied for relaxation and stress markers. Its degree of blood–brain barrier passage remains debated, with peripheral and enteric mechanisms proposed.

NMDA modulation, neuropathic calm

A decarboxylated arginine metabolite that modulates NMDA receptors, imidazoline receptors, and nitric oxide synthase. Studied for mood, neuropathic discomfort, and blunting stimulant tolerance.

Chamomile flavone, gentle sedation

A flavone concentrated in chamomile that binds benzodiazepine sites on GABA-A receptors, studied for sleep onset, anxiety, and mild aromatase inhibition.

Pineal telomerase signaling

Synthetic tetrapeptide (Ala-Glu-Asp-Gly) modeled on the pineal extract epithalamin. Studied in Khavinson's work for melatonin rhythm normalization, telomerase expression, and age-related endocrine decline.

Neuronal antihypoxic tripeptide

Synthetic tripeptide (Glu-Asp-Arg) that crosses into neural tissue and is researched for neuroprotection under hypoxic and oxidative stress, and for effects on learning and memory consolidation in animal models.

Vascular endothelial regulation

Synthetic tripeptide (Lys-Glu-Asp) directed at the vascular wall. Studied for endothelial cell function, vascular tone, and age-related changes in the arterial lining.

Cortical peptide regulator

Synthetic tetrapeptide (Ala-Glu-Asp-Pro) modeled on brain cortex extracts. Studied for cortical neuron recovery after injury, peripheral nerve regeneration, and inflammatory signaling in nervous tissue.

Natural pineal complex

Natural peptide complex extracted from pineal tissue, the parent preparation behind the synthetic epithalamin line. Studied for circadian and melatonin rhythm, neuroendocrine regulation, and age-related decline of the pineal axis.

Natural brain complex

Natural peptide complex from central nervous tissue. Studied for neuronal metabolism, cognitive function, and recovery of nervous tissue after ischemic or toxic insult.

Retinal peptide complex

Natural retinal peptide complex. Researched for photoreceptor and pigment epithelium function in degenerative retinal conditions and age-related visual decline.

Vascular peptide complex

Natural vessel-wall peptide complex. Researched for endothelial function, capillary perfusion, and age-related stiffening of the arterial wall.

Adrenal cortex complex

Natural adrenal peptide complex. Researched for adrenocortical function, glucocorticoid and mineralocorticoid signaling, and stress-axis regulation.

Cortical polypeptide neuroprotectant

Low-molecular-weight polypeptide fraction from cerebral cortex, used clinically in Russia and neighboring countries for stroke recovery, encephalopathy, and pediatric developmental conditions. Studied for neurotrophic signaling and neuronal survival under ischemia.

Retinal polypeptide neuroprotectant

Polypeptide complex from retinal tissue used clinically in several post-Soviet jurisdictions for degenerative and dystrophic retinal disease. Researched for photoreceptor survival, retinal microcirculation, and optic nerve function.

Long-acting GHRH analog

Modified growth-hormone-releasing hormone analog engineered for extended half-life, studied for amplification of endogenous GH pulse amplitude rather than exogenous replacement. Available only as a research compound in most jurisdictions and not an approved medicine.

Selective ghrelin-receptor agonist

Pentapeptide ghrelin receptor (GHS-R1a) agonist noted for releasing GH with comparatively little effect on cortisol or prolactin. Researched for body composition and recovery; a research compound rather than an approved therapeutic.

GHRH fragment secretagogue

The first 29 amino acids of native GHRH, historically used as a diagnostic and therapeutic agent for GH deficiency. Studied for restoring physiological GH pulsatility; obtained through prescription or compounding under physician supervision.

Synthetic GH-releasing hexapeptide

Ghrelin receptor agonist studied for strong GH release with modest concurrent rises in prolactin and cortisol. Used in research and in GH-deficiency diagnostic testing; not an approved therapeutic in most jurisdictions.

Oral non-peptide secretagogue

Orally bioavailable non-peptide ghrelin receptor agonist that raises GH and IGF-1 over sustained periods. Investigated in clinical trials for sarcopenia and frailty but never approved; sold only as a research chemical.

Innate repair receptor agonist

Non-hematopoietic erythropoietin-derived peptide that activates the innate repair receptor. Investigated in clinical trials for small-fiber neuropathy and neuropathic pain, particularly in sarcoidosis and diabetes; not an approved medicine.

Long-acting GLP-1 agonist

Acylated GLP-1 receptor agonist that slows gastric emptying, augments glucose-dependent insulin secretion, and acts on hypothalamic appetite circuits. Approved as a prescription medicine for type 2 diabetes and obesity; prescription-only under physician supervision.

Dual GIP/GLP-1 agonist

Single peptide acting at both the GIP and GLP-1 receptors, studied for glycemic control and weight reduction with effects on insulin sensitivity and lipid handling. Approved as a prescription medicine and used under physician supervision.

Triple incretin receptor agonist

Investigational agonist at the GIP, GLP-1, and glucagon receptors, the glucagon arm adding hepatic energy expenditure to incretin appetite and glycemic effects. In late-stage clinical trials and not an approved medicine.

Mitochondrial cytoprotective peptide

Mitochondrially encoded peptide studied for cytoprotection against apoptotic and oxidative stress, insulin sensitivity, and associations with human longevity. Research-stage with no clinical approval.

ACTH fragment, BDNF upregulation

Heptapeptide analog of an ACTH(4-10) fragment stripped of corticotropic activity, studied for BDNF and NGF expression, attention, and neuroprotection after ischemia. Registered as a medicine in Russia and unapproved elsewhere.

Tuftsin analog anxiolytic

Heptapeptide analog of the immune peptide tuftsin researched for anxiolytic effects via GABAergic and enkephalin-degrading enzyme modulation, without sedation or dependence in the available data. Registered in Russia; a research compound elsewhere.

HGF-potentiating synaptogenic peptide

Angiotensin IV-derived peptidomimetic studied for potentiating hepatocyte growth factor signaling at the c-Met receptor and promoting synaptogenesis in preclinical cognition models. Early-stage research compound with no human trial data.

Porcine neuropeptide preparation

Standardized mixture of low-molecular-weight peptides and amino acids from porcine brain, studied in stroke, traumatic brain injury, and dementia trials for neurotrophic-like activity. Approved in a number of countries and unavailable in others.

CNTF-derived neurogenic peptide

Synthetic peptide derived from ciliary neurotrophic factor, researched in animal models for neurogenesis, dendritic development, and reduction of tau hyperphosphorylation. Preclinical research compound.

Microtubule-stabilizing ADNP fragment

Octapeptide fragment of activity-dependent neuroprotective protein studied for microtubule stabilization and tau pathology. Reached phase 3 trials in progressive supranuclear palsy without meeting endpoints; not an approved medicine.

Zinc-dependent thymic nonapeptide

Nonapeptide thymic hormone requiring zinc for biological activity, studied for T-cell differentiation, neuroendocrine-immune crosstalk, and analgesic and anti-inflammatory effects. Research-stage, with zinc status a determinant of its activity.

Seco-steroid calcium regulator

A seco-steroid hormone precursor studied for calcium homeostasis, immune modulation, and parathyroid hormone suppression. Researched across bone, mood, and innate-immunity endpoints.

Lipid peroxidation brake

The classical chain-breaking antioxidant of cell membranes, studied for limiting polyunsaturated fat peroxidation and for estrogen-opposing effects described in the early vitamin E literature. Its requirement scales with the polyunsaturated fat content of tissue, since alpha-tocopherol is consumed in terminating lipid radical chain reactions.

Unsaturated vitamin E fraction

The unsaturated-tail members of the vitamin E family, researched for cholesterol-pathway modulation via HMG-CoA reductase and for membrane antioxidant activity distinct from tocopherols.

Calcium trafficking carboxylase cofactor

The animal-tissue form of vitamin K2, studied for activating matrix Gla protein and osteocalcin to direct calcium toward bone and away from soft tissue. MK-4 is the form tissues synthesize from other vitamin K precursors, and it carries additional research interest in mitochondrial electron transport.

Pyruvate dehydrogenase gatekeeper

The rate-limiting cofactor for pyruvate dehydrogenase and transketolase, studied for supporting complete glucose oxidation over lactate production. It sits at the entry point of oxidative metabolism, where thiamine status determines whether pyruvate is oxidized or diverted to lactate.

Lipid-soluble thiamine derivative

A synthetic S-acyl thiamine derivative with higher tissue availability, researched for advanced glycation end-product formation and nerve-related endpoints in the context of glucose metabolism.

Flavoprotein electron shuttle

Precursor to FAD and FMN, the flavin cofactors of the electron transport chain and fatty-acid oxidation. Studied for migraine frequency, and distinctive among the B vitamins for its photochemistry: flavins absorb blue light, which both degrades the vitamin and underlies its participation in light-driven redox reactions.

NAD+ pool without flush

The amide form of vitamin B3 and a direct NAD+ precursor, studied for supporting the NAD+/NADH ratio, restraining excessive lipolysis, and skin-related endpoints. Unlike nicotinic acid it does not provoke the flush response, because it does not activate the GPR109A receptor on dermal immune cells.

Transamination and neurotransmitter cofactor

As pyridoxal-5-phosphate, the universal cofactor for amino acid transamination and the synthesis of dopamine, GABA, and serotonin. Studied for prolactin modulation, homocysteine metabolism, and nerve function.

Carboxylase and glucose-oxidation cofactor

Cofactor for the carboxylase enzymes of gluconeogenesis, fatty-acid synthesis, and anaplerosis, studied for glucose handling and keratin-related endpoints. Through pyruvate carboxylase it governs the branch point where pyruvate replenishes the citric acid cycle, and its status has been examined in relation to glucose tolerance and insulin sensitivity.

One-carbon methylation currency

The central carrier of one-carbon units for nucleotide synthesis and methylation, studied for homocysteine control, red blood cell formation, and neurodevelopmental endpoints.

Methionine synthase methyl donor

The active methyl form of B12, cofactor for methionine synthase and methylmalonyl-CoA mutase, researched for nerve conduction, red blood cell maturation, and homocysteine metabolism.

Second-messenger insulin mimetic

A cyclic polyol acting in phosphoinositide second-messenger signaling, studied for insulin sensitivity, ovarian function, and anxiety-related endpoints.

ATP-stabilizing relaxation mineral

A well-absorbed chelate pairing magnesium — the counter-ion of ATP and cofactor for over 300 enzymes — with glycine. Studied for sleep quality, muscle relaxation, and stress-axis buffering; because cellular magnesium retention depends on thyroid status and energy charge, serum levels can read as normal while tissue stores are depleted.

Androgenic and immune metalloenzyme core

A catalytic and structural component of hundreds of enzymes and zinc-finger transcription factors, studied for testosterone support, immune competence, and skin integrity.

Cytochrome oxidase keystone

The metal center of cytochrome c oxidase, the terminal enzyme of the electron transport chain, and of ceruloplasmin. Because cytochrome c oxidase cannot function without its copper centers, availability of the mineral can become rate-limiting for respiration itself; also studied for iron handling, connective tissue cross-linking, and pigmentation.

Free-testosterone and bone modulator

A trace element researched for raising free testosterone fraction, lowering sex hormone-binding globulin, and supporting bone and joint metabolism alongside vitamin D.

Low-dose mood stabilization

A nutritional lithium salt studied for GSK-3 inhibition, neurotrophic signaling, and mood stability at trace intakes far below pharmaceutical lithium therapy.

Mitochondrial superoxide dismutase metal

The metal center of mitochondrial superoxide dismutase (MnSOD) and a cofactor for glycosylation and urea-cycle enzymes, studied for connective tissue formation and antioxidant defense.

Inhibitory anti-stress amino acid

The simplest amino acid, acting as an inhibitory neurotransmitter at glycine receptors and a substrate for collagen and glutathione. Studied for sleep quality, for offsetting the methionine load of muscle-meat protein, and for its calming, anti-excitotoxic profile.

Osmolyte and bile conjugator

A sulfonic amino acid concentrated in heart, retina, and brain, studied for bile acid conjugation, cellular osmoregulation, GABAergic tone, and cardiovascular endpoints. Conjugating bile acids with taurine keeps them soluble across a wider pH range, supporting hepatic export of cholesterol and fat emulsification.

Serotonin-antagonist essential amino

An essential amino acid studied for herpes-virus suppression through competition with arginine, for collagen cross-linking, and for partial antagonism of intestinal serotonin receptors — an effect examined in research on anxiety and bowel function.

Phosphagen energy buffer

The most extensively studied ergogenic compound, buffering ATP through the phosphocreatine system. Researched for strength, lean mass, and increasingly for cognitive performance under sleep deprivation.

Electron transport chain carrier

The reduced form of coenzyme Q10, the mobile electron carrier between complexes I/II and III of the respiratory chain. Studied for cardiac function, statin-associated muscle symptoms, and fertility endpoints.

Mitochondrial biogenesis signal

A redox cofactor studied for stimulating mitochondrial biogenesis via PGC-1alpha signaling and for neurotrophic effects, including nerve growth factor expression.

Direct NAD+ precursor

A nucleotide precursor one enzymatic step from NAD+, researched for age-related NAD+ decline, insulin sensitivity, and vascular endpoints in human trials.

Salvage-pathway NAD+ support

A B3-family riboside entering the NAD+ salvage pathway through NRK kinases, studied for raising blood NAD+ levels and for metabolic and neurodegenerative research endpoints.

Dithiol dehydrogenase cofactor

A sulfur-containing cofactor of the pyruvate and alpha-ketoglutarate dehydrogenase complexes, studied for glucose disposal, nerve-related endpoints, and regeneration of other antioxidants.

NAD+/NADH ratio shifter

An ester blend of pyruvate and acetoacetate. Esterification lets both substrates cross membranes readily, where they act as electron acceptors that shift the cytosolic and mitochondrial redox ratio toward oxidation, favoring glucose use over fatty-acid oxidation.

Fulvic acid CoQ10 stabilizer

A mineral-rich exudate containing fulvic acid and dibenzo-alpha-pyrones, researched for stabilizing CoQ10 in its reduced form, supporting testosterone, and exercise-recovery endpoints.

Portal-vein ketogenic substrate

Purified medium-chain triglycerides absorbed directly to the portal vein and oxidized without carnitine transport, studied for rapid ketone generation, satiety, and cognitive-energy endpoints.

Colonocyte fuel and HDAC brake

The four-carbon short-chain fatty acid that serves as the primary fuel of colonocytes, studied for gut barrier integrity, histone deacetylase inhibition, and metabolic signaling through GPR receptors.

Contested long-chain polyunsaturates

Marine long-chain fatty acids studied extensively for triglyceride lowering, cardiovascular endpoints, and membrane composition of the brain and retina. The optimal level of polyunsaturated fat intake remains genuinely debated: the same double bonds that give these fatty acids their membrane and signaling properties also make them susceptible to peroxidation, and large randomized trials have returned mixed results on hard clinical endpoints.

Phospholipid and choline vehicle

Egg-derived phospholipids rich in phosphatidylcholine, studied for choline provision, bile flow, and lipid transport. The yolk source carries a higher proportion of phosphatidylcholine and a different fatty-acid profile than soy-derived lecithin.

Prostaglandin suppression uncoupler

Acetylsalicylic acid, an irreversible cyclooxygenase inhibitor and one of the most-studied molecules in medicine. Beyond blocking inflammatory prostaglandin synthesis from arachidonic acid, it has been researched for mild mitochondrial uncoupling, restraint of lipolysis, anti-serotonin and anti-estrogen effects, and support of oxidative glucose metabolism. Large clinical literatures cover cardiovascular event prevention and colorectal-cancer epidemiology, alongside well-documented bleeding and gastric considerations that place its use in clinical context.

Sirtuin-pathway stilbene

A grape-derived stilbene researched for sirtuin activation, aromatase inhibition, and cardiovascular markers, with human data notably more modest than its preclinical literature.

Master intracellular thiol

The dominant intracellular thiol antioxidant and conjugation substrate of phase II detoxification, studied in liposomal and precursor forms for oxidative-stress markers and liver support.

Cysteine donor mucolytic

The acetylated cysteine prodrug that rate-limits glutathione synthesis, studied for acetaminophen overdose rescue, mucus viscosity, and compulsive-behavior research in psychiatry.

Non-tolerance purine alkaloid

A caffeine-related purine alkaloid from kucha tea, studied for energy and mood endpoints with reportedly less receptor tolerance than caffeine, alongside preclinical antioxidant and anti-inflammatory signaling data.

The active thyroid hormone

Synthetic triiodothyronine, the biologically active thyroid hormone that binds nuclear thyroid receptors to set mitochondrial respiration, oxygen consumption, and basal metabolic rate, with body temperature and resting pulse serving as clinical correlates of metabolic output. Prescription-only: indicated for hypothyroidism and studied in refractory depression, and must be prescribed and monitored by a physician with regular thyroid panels, as excess produces tachycardia, bone loss, and arrhythmia.

Storage-form thyroid prohormone

Synthetic thyroxine, the long-half-life storage form the body deiodinates to active T3, largely in liver and peripheral tissue, so conversion capacity, liver health, and reverse-T3 are the variables that decide whether T4 alone reaches the cell as active hormone. Prescription-only and the standard first-line treatment for hypothyroidism, prescribed and titrated by a physician against TSH and free-hormone labs.

Whole-gland porcine extract

Standardized porcine thyroid extract supplying both T4 and T3 alongside trace thyroid constituents, the preparation that predates synthetic hormones and is still used for its combined delivery of both hormones in a fixed ratio. Prescription-only: prescribed for hypothyroidism and monitored by a physician, since potency conventions differ between preparations and dose-equivalence with synthetic hormone is not straightforward.

Ratio-matched dual replacement

Combined liothyronine and levothyroxine therapy, studied for patients who remain symptomatic on T4 monotherapy — a group in which impaired peripheral deiodination is the proposed explanation; supplying T3 directly keeps active hormone available without placing the entire load on conversion. Prescription-only, compounded or co-prescribed and monitored by a physician, with the T3 fraction being the component that most readily overshoots.

Esterified androgen replacement

Long-acting esters of testosterone that hydrolyze to free hormone and act on the androgen receptor across muscle, bone, brain, and reproductive tissue, with a fraction aromatized to estradiol and reduced to DHT. Prescription-only and a controlled substance in most jurisdictions: indicated for diagnosed male hypogonadism and prescribed and monitored by a physician, with follow-up on hematocrit, estradiol, lipids, prostate markers, and suppression of endogenous production.

Transdermal androgen delivery

Gel, cream, or solution formulations delivering testosterone through skin for steadier daily serum levels than injected esters, with greater local conversion to DHT by cutaneous 5-alpha-reductase. Prescription-only and controlled in most jurisdictions: prescribed for hypogonadism and monitored by a physician, who also counsels on transfer to partners and children through skin contact.

Weak downstream androgen metabolite

A 5-alpha-reduced metabolite of DHT and testosterone with weak androgen-receptor activity, studied as a neurosteroid at GABA-A receptors and as a non-aromatizable androgen with possible aromatase-inhibiting activity. Regulatory status varies by jurisdiction and it is prescription-only or restricted in many; human evidence is limited, and use to alter androgen status should occur only under physician supervision with hormone monitoring.

Non-aromatizable pure androgen

Dihydrotestosterone applied transdermally — the highest-affinity androgen-receptor ligand, which cannot be aromatized to estrogen and therefore raises androgenic signaling without adding to estradiol. Prescription-only where it is available at all (unapproved in many countries): prescribed and monitored by a physician, with attention to profound suppression of endogenous testosterone, prostate effects, and scalp hair.

Upstream adrenal androgen precursor

Dehydroepiandrosterone, the most abundant circulating adrenal steroid and a precursor that tissues convert to both androgens and estrogens; it declines steeply with age and is studied in adrenal insufficiency and in diminished ovarian reserve. Prescription-only in most countries outside the United States and banned in some sport contexts: because downstream conversion is unpredictable and can raise estradiol, it should be taken only under physician supervision with hormone monitoring.

Apex steroid precursor

The first steroid made from cholesterol and the common precursor to progesterone, DHEA, cortisol, and the sex hormones, also acting in its own right on microtubules and NMDA signaling in brain, and studied for its influence on the balance between stress steroids and the rest of the steroid profile. Its legal status varies by jurisdiction and it is prescription-only in many countries; because it feeds directly into the adrenal and gonadal cascade, it should be used only under physician supervision with hormone monitoring.

Anti-estrogenic protective progestogen

The bioidentical progestogen, indicated for endometrial protection in menopausal hormone therapy and in luteal support, and studied for sleep and mood through its conversion to allopregnanolone; physiologically it acts as the principal counterweight to estrogen at the receptor and tissue level. Prescription-only in most jurisdictions: prescribed and monitored by a physician, since it interacts with the entire steroid axis rather than acting in isolation.

GABA-A positive neurosteroid

A progesterone metabolite and potent positive allosteric modulator of the GABA-A receptor; its synthetic analogue brexanolone is approved for postpartum depression, and the class is studied more broadly in mood and seizure disorders. Prescription-only and administered in supervised clinical settings, prescribed and monitored by a physician because of pronounced sedation and loss-of-consciousness risk.

LH-mimetic gonadotropin

Human chorionic gonadotropin, which binds the LH receptor on testicular Leydig cells and ovarian theca cells to stimulate steroidogenesis directly, bypassing the pituitary; indicated in hypogonadotropic hypogonadism, ovulation induction, and cryptorchidism, and used clinically to preserve testicular function and fertility during androgen therapy. Prescription-only, prescribed and monitored by a physician.

Selective pituitary estrogen antagonist

The trans-isomer of clomiphene, a selective estrogen receptor modulator that blocks estrogenic negative feedback at the hypothalamus and pituitary to raise LH, FSH, and endogenous testosterone while leaving spermatogenesis intact. Prescription-only and, in most jurisdictions, prescribed off-label for secondary hypogonadism and monitored by a physician with periodic hormone panels.

Gonadotropin-releasing SERM

A mixed isomer selective estrogen receptor modulator indicated for ovulation induction in anovulatory infertility and prescribed off-label for male secondary hypogonadism, working by relieving estrogen feedback on the hypothalamic-pituitary axis. Prescription-only: prescribed and monitored by a physician, with attention to visual disturbances, mood effects, and multiple-gestation risk in fertility use.

Synthetic GnRH decapeptide

Synthetic gonadotropin-releasing hormone, which acts on pituitary gonadotrophs to trigger LH and FSH release; used diagnostically to test pituitary responsiveness and therapeutically in hypothalamic hypogonadism, where the pulsatile pattern of exposure determines whether the axis is stimulated or downregulated. Prescription-only, prescribed and monitored by a physician.

Upstream GnRH trigger

The hypothalamic neuropeptide that sits upstream of GnRH neurons and gates the onset of puberty and reproductive signaling; it is investigational, studied in hypothalamic amenorrhea, fertility protocols, and sexual-response research. Prescription-only and largely confined to clinical trials, appropriate only under physician supervision within a research or specialist endocrine setting.

Combined FSH-LH activity

Human menopausal gonadotropin, a urinary-derived preparation carrying both FSH and LH activity, indicated for follicular development in assisted reproduction and for stimulating spermatogenesis in hypogonadotropic hypogonadism. Prescription-only, prescribed and monitored by a physician — in fertility use with ultrasound and estradiol tracking because of ovarian hyperstimulation risk.

Tissue-selective estrogen blocker

A selective estrogen receptor modulator that antagonizes the receptor in breast tissue while acting as a partial agonist in bone and liver; indicated in breast cancer treatment and risk reduction and prescribed for gynecomastia. Prescription-only: prescribed and monitored by a physician, with attention to thromboembolic and endometrial risk.

Dopamine D2 prolactin suppressant

A long-acting dopamine D2 receptor agonist indicated for hyperprolactinemia and prolactin-secreting pituitary adenomas, acting on lactotroph cells to suppress prolactin secretion and shrink tumor mass. Prescription-only: prescribed and monitored by a physician, with echocardiographic surveillance for valvular fibrosis in longer courses and attention to impulse-control and hypotensive effects.

Bioidentical glucocorticoid replacement

Bioidentical cortisol used as physiologic replacement in primary and secondary adrenal insufficiency, restoring glucocorticoid signaling for gluconeogenesis, vascular tone, and stress response. Prescription-only and prescribed and monitored by a physician, who also manages illness-related adjustment and the suppression of endogenous adrenal output that accompanies exogenous glucocorticoid.

HPA-axis cortisol blunting

A membrane phospholipid studied for blunting ACTH and cortisol responses to acute physical and psychological stress and for supporting cognition in older adults, with modest and mixed human trial evidence. Available without prescription, but because it acts on the HPA axis its use for cortisol management should be supervised by a physician, particularly alongside corticosteroid or anticoagulant therapy.