CID 6013

C₁₉H₂₈O₂

Testosterone

C 19
H 28
O 2

Ball-and-stick Stick Space-filling

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49 atoms, 52 bonds.

IUPAC name: (8R,9S,10R,13S,14S,17S)-17-hydroxy-10,13-dimethyl-1,2,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-3-one
Molar mass: 288.431(46) g/mol
Atoms: 49
SMILES: CC12CCC3C(C1CCC2O)CCC4=CC(=O)CCC34C
InChIKey: MUMGGOZAMZWBJJ-DYKIIFRCSA-N
PubChem CID: 6013

Made of

C H O

Structural formula of testosterone. Each unlabelled corner is a carbon atom, and the 21 hydrogens on carbon are not drawn. Wedges come toward you, hashes go back. It shows which atoms are joined to which, not the shape. The model above shows the shape.

Often called the male sex hormone, testosterone is present in both sexes. A hormone, as MedlinePlus defines the word, is a chemical messenger in the bloodstream that controls what certain cells or organs do. The Hazardous Substances Data Bank (HSDB) ranks testosterone as the body’s principal androgen, a hormone that develops male sexual characteristics.

One molecule holds 19 carbon, 28 hydrogen and 2 oxygen atoms, C₁₉H₂₈O₂, which makes its molar mass 288.4 g/mol. The pure substance forms white or faintly cream crystals. Its solubility in water is 23.4 mg per litre at 25 °C on HSDB’s figure, while vegetable oils, alcohol and other organic solvents dissolve it.

It was first isolated in 1935, as crystals obtained from animal testes, according to HSDB. The US National Institute on Drug Abuse (NIDA) places the first synthesis in the same year.

Structure and bonding

Testosterone’s 19 carbon atoms divide into 17 that form four rings and two that are methyl groups, CH₃. The rings stand in a row, three of six carbons then one of five, and each methyl sits on a carbon two rings share. No carbon side chain branches off, and ChEBI, the Chemical Entities of Biological Interest database, classes it as a C19-steroid.

The two O symbols that Labels prints mark opposite ends, 10.9 Å apart in this computed model. One belongs to an O–H group on the five-membered ring. The other is double-bonded to a carbon in the farthest six-membered ring, and Ball-and-stick shows that ring’s one C=C a single bond away. Chem1 calls this alternation a conjugated system; the butadiene page describes how electrons spread through one.

Every other bond is single. Each of the three double-bonded carbons has its three neighbours spread flat around it, and the other 16 hold four in the roughly tetrahedral pattern Chem1 describes. Stick strips the model to its 52 bonds, and Space-filling packs 28 hydrogens around the frame. The IUPAC name tags six carbons R or S, each chiral as the lactic acid page explains.

Where it turns up

In males the testes are the main producers, and Medical Subject Headings (MeSH) names their Leydig cells as the source. Luteinising hormone (LH) from the pituitary gland stimulates production, and testosterone in turn exerts feedback control over the pituitary’s release of LH and follicle-stimulating hormone. Females have smaller amounts, and the adrenal glands also supply sex steroids, testosterone among them. In blood, most testosterone is attached to proteins, among them sex-hormone-binding globulin (SHBG) and albumin. Keeping most of it bound, MedlinePlus explains, makes sure the body does not use too much.

HSDB traces the synthetic commercial supply to cholesterol. The US Food and Drug Administration (FDA) lists a skin gel, a skin patch and an injection among the approved forms. The liver metabolises testosterone rapidly, so the medicine is generally given as an ester derivative, a chemically modified form, according to the US National Cancer Institute’s NCI Thesaurus.

Why it matters

Testosterone works by binding a protein called the androgen receptor. Receptor and hormone form an androgen-receptor complex, which then binds DNA and regulates the activity of certain genes, as MedlinePlus Genetics describes it. A receptor that cannot bind androgens leaves the body unable to use them, even at normal hormone levels, as in androgen insensitivity syndrome. The enzyme steroid 5-alpha reductase 2 converts testosterone into dihydrotestosterone (DHT), which the NCI Thesaurus describes as binding the same receptor with higher affinity. Aromatase, an enzyme complex, converts testosterone irreversibly into estradiol.

The growth spurt normally starts as testosterone and the other sex hormones rise, and NIDA reports that the same rise also signals growth to stop. Anabolic steroids, in NIDA’s definition, are synthetic substances similar to testosterone that promote skeletal-muscle growth and male sexual characteristics. Misused by a child or adolescent, they can tell the bones to stop growing early. NIDA warns that anabolic steroids can lead to strokes, early heart attacks, kidney failure, liver tumours and psychiatric problems.

Properties

Properties of testosterone Molar mass summed from IUPAC/CIAAW 2024 standard atomic weights; formula, atom and bond counts and PubChem's molecular weight from PubChem CID 6013.
Property	Value	Unit	Source
Molecular formula (Hill order)	C₁₉H₂₈O₂
Molar mass	288.431(46) g/mol	g/mol	IUPAC/CIAAW 2024
Carbon atoms	19
Hydrogen atoms	28
Oxygen atoms	2
Bonds	52
Single bonds	50
Double bonds	2
PubChem molecular weight	288.4 g/mol	g/mol	PubChem

Safety

Testosterone is a prescription hormone and, in the United States, a Schedule III controlled substance. Its classification under the Globally Harmonized System (GHS), drawn from company reports to the European Chemicals Agency (ECHA), carries the signal word Danger. Of those reports, 76.2% state that it may damage fertility or the unborn child and 66.2% that it is suspected of causing cancer. The PubChem Laboratory Chemical Safety Summary for testosterone lists every statement.

Questions

Do women have testosterone?

Yes. Although testosterone is often thought of as a male sex hormone, MedlinePlus notes that females have it too, in smaller amounts. In both sexes it helps control sex drive and supports the growth of muscle and bone. NICHD, the US National Institutes of Health's institute for child health, counts the adrenal glands as an important source of sex steroids, testosterone included.

Is testosterone a controlled substance?

In the United States, yes. The Drug Enforcement Administration (DEA) places it in Schedule III, and federal regulation 21 CFR 1308.13(f) lists it among the anabolic steroids as 17β-hydroxyandrost-4-en-3-one. On NIDA's account, the Anabolic Steroid Act of 1990 made anabolic steroids a separate drug class and brought more than two dozen drugs under control. FDA approves testosterone products only for men who lack the hormone or have low levels alongside an associated medical condition.

What is DHT?

DHT, dihydrotestosterone, is a hormone the body makes from testosterone, a conversion carried out by the enzyme steroid 5-alpha reductase 2, according to MedlinePlus Genetics. Both hormones bind the androgen receptor, DHT with the higher affinity on the NCI Thesaurus's account. The thesaurus places the conversion in target tissues and calls it irreversible. Before birth, too little DHT disturbs how the external sex organs of a genetically male child form.

How many rings does testosterone have?

Four, standing in a row: three rings of six carbon atoms and one of five. Each neighbouring pair shares a C–C bond, so two carbons belong to both rings, and the 23 ring positions come down to 17 atoms. Two methyl carbons bring the count to 19. With 28 hydrogens and 2 oxygens, the 3D model draws 49 atoms and 52 bonds, two of them double.

Made of the same elements

C₂₁H₃₀O₂ Progesterone 53 atoms, 56 bonds.
C₁₈H₂₄O₂ Estradiol 44 atoms, 47 bonds.
C₂₁H₃₀O₅ Cortisol 56 atoms, 59 bonds.
C₁₈H₃₄O₂ Oleic acid 54 atoms, 53 bonds.
C₁₆H₃₂O₂ Palmitic acid 50 atoms, 49 bonds.
C₁₅H₁₆O₂ Bisphenol A 33 atoms, 34 bonds.
C₁₃H₁₈O₂ Ibuprofen 33 atoms, 33 bonds.
C₂₀H₁₄O₄ Phenolphthalein 38 atoms, 41 bonds.

All 51 compounds made of carbon, hydrogen and oxygen

C₁₀H₂₀O Menthol 31 atoms, 31 single bonds.
C₁₄H₁₄O₃ Naproxen 31 atoms, 32 bonds.
C₁₂H₂₂O₁₁ Lactose 45 atoms, 46 single bonds.
C₁₂H₂₂O₁₁ Sucrose 45 atoms, 46 single bonds.
C₂₇H₄₄O Cholecalciferol 72 atoms, 74 bonds.
C₂₇H₄₆O Cholesterol 74 atoms, 77 bonds.
C₉H₈O₄ Aspirin 21 atoms, 21 bonds.
C₈H₈O₃ Methyl salicylate 19 atoms, 19 bonds.
C₈H₈O₃ Vanillin 19 atoms, 19 bonds.
C₆H₁₂O₆ Fructose 24 atoms, 24 single bonds.
C₆H₁₂O₆ Glucose 24 atoms, 24 single bonds.
C₄H₉OH 1-Butanol 15 atoms, 14 single bonds.
C₆H₅COOH Benzoic acid 15 atoms, 15 bonds.
C₂H₅OC₂H₅ Diethyl ether 15 atoms, 14 single bonds.
C₆H₅CHO Benzaldehyde 14 atoms, 14 bonds.
C₃H₇COOH Butyric acid 14 atoms, 13 bonds.
CH₃COOC₂H₅ Ethyl acetate 14 atoms, 13 bonds.
C₇H₆O₃ Salicylic acid 16 atoms, 16 bonds.
C₄H₈O Butanone 13 atoms, 12 bonds.
C₆H₅OH Phenol 13 atoms, 13 bonds.
C₃H₈O₂ Propylene glycol 13 atoms, 12 single bonds.
C₃H₇OH 1-Propanol 12 atoms, 11 single bonds.
C₆H₈O₆ Ascorbic acid 20 atoms, 20 bonds.
C₃H₈O₃ Glycerol 14 atoms, 13 single bonds.
C₃H₈O Isopropyl alcohol 12 atoms, 11 single bonds.
C₆H₈O₇ Citric acid 21 atoms, 20 bonds.
C₂H₅COOH Propionic acid 11 atoms, 10 bonds.
C₃H₆O Acetone 10 atoms, 9 bonds.
C₂H₆O₂ Ethylene glycol 10 atoms, 9 single bonds.
C₃H₆O₃ Lactic acid 12 atoms, 11 bonds.
CH₃OCH₃ Dimethyl ether 9 atoms, 8 single bonds.
C₂H₅OH Ethanol 9 atoms, 8 single bonds.
C₄H₆O₅ Malic acid 15 atoms, 14 bonds.
CH₃COOH Acetic acid 8 atoms, 7 bonds.
C₄H₆O₆ Tartaric acid 16 atoms, 15 bonds.
CH₃CHO Acetaldehyde 7 atoms, 6 bonds.
C₂H₄O Ethylene oxide 7 atoms, 7 single bonds.
C₂H₄O₃ Glycolic acid 9 atoms, 8 bonds.
CH₃OH Methanol 6 atoms, 5 single bonds.
HCOOH Formic acid 5 atoms, 4 bonds.
H₂CO₃ Carbonic acid 6 atoms, 5 bonds.
CH₂O Formaldehyde 4 atoms, 3 bonds.
H₂C₂O₄ Oxalic acid 8 atoms, 7 bonds.