Androgens and appearance: a glossary with a real number behind every term

You have just read a thread where four people used “free T,” “SHBG,” and “DHT” as if those labels settled what your face says to strangers. They do not. They name measurements, binding proteins, enzymes, and receptors; they are not a facial verdict.

The useful distinction is timing. A hormone measured in cord blood can track adult facial masculinity, while a circulating adult result can show no relationship at all. That is the fact most appearance threads skip because it ruins the easy story.

These are definitions and published figures, not advice. Blood results belong to a clinician who has your whole history, and FDA drug figures below are label facts, not recommendations. A definition without a number is decoration, so every entry carries a real figure or an honest statement that the popular figure could not be sourced.

Key numbers

• 264 to 916 ng/dL: Harmonized total testosterone range for men aged 19 to 39 (PubMed 28324103).
• 9,054 men: Community-dwelling men behind those harmonized percentiles (PubMed 28324103).
• 40% and 2%: Approximate SHBG-bound and unbound circulating testosterone (DailyMed testosterone label).
• 65%: Serum DHT suppression within 24 hours of finasteride 1 mg (DailyMed finasteride 1 mg label).
• 85%, 90%, 94%: Dutasteride serum DHT suppression across its label timeline (DailyMed dutasteride label).
• 105 Hz and 63 Hz: Measured pubertal falls in fundamental frequency (PubMed 27853555).
• r = -0.55 versus r = 0.01: Cord-blood versus adult testosterone facial association (PubMed 26400740).

Table of contents

• The measurement words
• The enzyme words
• The receptor words
• The visible-trait words
• The oestrogen words
• The prenatal words, and the one that matters most
• Five claims we could not source
• How to cite this page
• The bottom line
• Sources

The measurement words

These words describe what testosterone is doing in a blood sample. They help explain why two results can disagree, but none converts a lab value into a reliable prediction of your face.

Total testosterone. Total T includes testosterone in all circulating forms. In healthy non-obese men aged 19 to 39, the harmonized range was 264 to 916 ng/dL, derived from 9,054 men; the FDA label gives 300 to 1000 ng/dL and calls for morning confirmation on at least two separate days (PubMed 28324103; DailyMed).

Free testosterone. Free T is the unbound fraction, not “the testosterone your face gets.” About 2% is unbound; in a population survey, 11% of men had calculated free testosterone below 5 ng/dL while 24% had total testosterone below 300 ng/dL (PubMed 17698901).

Bioavailable testosterone. Bioavailable T generally means free testosterone plus the loosely albumin-bound portion. In a survey of 1,475 men aged 30 to 79, symptomatic androgen deficiency was 5.6%; calculated free T from total T and SHBG was almost identical to equilibrium dialysis as an index of bioavailability (PubMed 10523012; PubMed 17698901).

SHBG. Sex hormone-binding globulin is the high-affinity carrier that holds about 40% of circulating testosterone. In the Massachusetts Male Aging Study, SHBG rose 1.6% per year of age while total testosterone declined 0.8% per year (PubMed 11836290).

Albumin-bound testosterone. Albumin-bound T is loosely held and can contribute to the bioavailable pool. It declined with age at about 2% per year, roughly twice the cross-sectional rate reported for total testosterone (PubMed 11836290).

Diurnal variation. Testosterone is not a fixed daily number. With blood sampled every 30 minutes over 24 hours, every subject showed a fall of at least 43% from peak to nadir; total, free, and bioavailable testosterone peaked around 07.00 h, while SHBG peaked at 15.12 h in young men and 15.40 h in middle-aged men (PubMed 12780747).

The enzyme words

These terms explain how testosterone becomes DHT and how the labels for finasteride and dutasteride quantify that change. The drug figures are prescribing-label facts, not instructions to use, stop, or adjust anything.

5-alpha-reductase (type I and type II). Type I predominates in sebaceous glands, including the scalp, and the liver, accounting for roughly one-third of circulating DHT; type II sits in the prostate, seminal vesicles, epididymides, and hair follicles. Finasteride is roughly 100-fold selective for type II, with IC50 values of 500 nM for type I and 4.2 nM for type II (DailyMed finasteride 1 mg label).

DHT. Dihydrotestosterone is a testosterone metabolite with stronger receptor binding, not a magic “potency” number. In human genital-skin fibroblasts it bound the androgen receptor with about 2-fold greater affinity than testosterone, while testosterone dissociated about 5 times faster; an older-men reference group had a DHT 2.5th percentile of 0.49 nmol/L (PubMed 2298157; PubMed 22977273).

Finasteride. The 1 mg label reports a 65% serum-DHT suppression within 24 hours of a single tablet, with mean testosterone and estradiol rising approximately 15% and remaining within the physiologic range. In 249 men biopsied before and after 42 days, scalp DHT fell 64.1% on 1 mg and serum DHT fell 71.4% (DailyMed finasteride 1 mg label; PubMed 10495374). For adverse-effect questions, see the finasteride side-effects guide.

Dutasteride. Dutasteride inhibits both isoforms. Its label reports median serum-DHT reductions of 85% after 1 week, 90% after 2 weeks, and 94% at 1 year; mean prostatic tissue DHT was 784 pg/g versus 5,793 pg/g on placebo (DailyMed dutasteride label).

The receptor words

Receptor vocabulary describes the receiving protein, not a direct measurement of facial masculinity. Small genetic differences can be biologically interesting without being useful as a personal appearance forecast.

Androgen receptor. The androgen receptor is the cellular protein that receives testosterone and DHT signals. The clearest comparison here is binding: DHT showed about 2-fold greater affinity than testosterone, while testosterone left the receptor about 5 times faster (PubMed 2298157).

AR CAG repeat polymorphism. This is variation in the length of a CAG repeat in the androgen-receptor gene. In 1,324 young men, the median length was 23, with a range of 6 to 39; a meta-analysis of 2,074 men with androgenetic alopecia and 1,115 controls found no association with risk, OR = 0.81, 95% CI 0.49-1.34, P = 0.41 (PubMed 36142533; PubMed 21981665).

The visible-trait words

These entries describe traits people can actually see or hear, and the population figures behind them are collected in testosterone statistics. They are closer to first impressions than a hormone label, but each still describes one contribution rather than a complete social read.

Androgenetic alopecia. This is pattern hair loss involving miniaturized follicles and increased DHT in balding scalp compared with hairy scalp; the prevalence and treatment numbers sit in male hair loss statistics. In 5,531 Korean men, Norwood III or above had an all-ages prevalence of 14.1%, rising from 2.3% in the third decade to 24.5% in the sixth (PubMed 11453914; DailyMed finasteride 1 mg label).

Beard density. Beard density is not scalp density moved to the lower face. In 580 men, follicular-unit density averaged 78.2/cm2 on donor scalp versus 49.7/cm2 in the beard, while hair density averaged 141.5/cm2 versus 65.6/cm2 (PubMed 31057266).

Seasonality of beard growth. Beard growth changes across the year. In 14 healthy men aged 18 to 39 followed every 28 days for 18 months, growth was lowest in January and February and peaked about 60% above the winter trough from March to July (PubMed 2003996).

Sebum. Sebum is oil produced by sebaceous glands, where type I 5-alpha-reductase is prominent. In a facial study, clascoterone cream 1% cut measured sebum 27% at week 12 and 22% at week 6; oral isotretinoin produced a 36% decline over 6 months in 35 patients (PubMed 40682762).

Fundamental frequency (F0). F0 is the acoustic rate that underlies perceived pitch. Adult men typically span 80 to 175 Hz and women 160 to 270 Hz; mean F0 fell 105 Hz between ages 7 and 14, then 63 Hz between 14 and 21, and reached 125 Hz at 12 months in a longitudinal testosterone study of trans men (PubMed 27853555; PubMed 26678122). More context is in the voice-pitch statistics guide.

The oestrogen words

Oestrogen is part of male endocrine biology, not the opposite of androgen biology. The figures below show why changing one pathway can move several hormones at once.

Estradiol in men. Estradiol is the principal oestrogen measured in men. In healthy men aged 70 to 89 measured by mass spectrometry, the 2.5th percentile was 28 pmol/L; that is an older-men reference band, not an all-adult range (PubMed 22977273).

Aromatase. Aromatase converts androgens toward estradiol, so blocking it changes the balance rather than simply “raising testosterone.” With anastrozole 1 mg daily for 12 weeks, bioavailable testosterone rose from 99 ± 31 ng/dL to 207 ± 65 ng/dL while estradiol fell from 26 ± 8 pg/mL to 17 ± 6 pg/mL; on finasteride, testosterone and estradiol both rose approximately 15% (PubMed 15856361; DailyMed finasteride 1 mg label).

The prenatal words, and the one that matters most

The prenatal-versus-circulating distinction is the page’s central point: the hormone signal that tracked a masculine adult face was measured at birth, not in an adult blood test you can book today.

2D:4D. This is the ratio of the second finger to the fourth finger, often used as an indirect prenatal-androgen marker. In the BBC Internet Study of 255,116 participants, mean right-hand 2D:4D was 0.984 in men and 0.994 in women; the measurement method changed the effect from d = 0.40 with photocopies to d = 0.17 for self-measured right hands and d = 0.04 for left hands. A meta-analysis of 7 to 8 samples, overall n = 362 to 469, found only a small, non-significant relationship with male facial attractiveness (PubMed 37847344; PubMed 24084044).

Prenatal versus circulating testosterone. In a 20-year follow-up, higher umbilical cord testosterone at birth predicted a more masculinized face at ages 21 to 24, with r = -0.55 in males. Adult circulating testosterone did not predict facial masculinity at all: r = 0.01, p = 0.93. The abstract’s sample counts are inconsistent, so no single total n belongs here (PubMed 26400740).

If you want to know how your face actually lands on people now, Real World Appeal’s free perception test measures that missing present-day axis rather than pretending a hormone glossary can do it. Your score is visible with no paywall on the score itself, and the test carries its own caveat: it is not a clinical instrument.

Five claims we could not source

These are not debunks. They are claims for which we searched the named evidence and found a narrower, different, or incomplete result.

“Testosterone drops 1% a year after thirty.” We searched the Massachusetts Male Aging Study and the paper routinely cited for the one-percent figure and found 0.8% per year cross-sectionally and about 1.6% per year longitudinally in a cohort aged 40 to 70 at baseline; nothing anchors that rate at age thirty (PubMed 11836290; PubMed 21632481).

“DHT is five times more potent than testosterone.” We searched the primary receptor measurement and found an affinity gap of about 2-fold; the 5-fold figure is the dissociation rate, not the affinity gap (PubMed 2298157).

“One bad night drops testosterone 15%.” We searched the cited sleep study and found that the 10 to 15% figure followed one week restricted to 5 hours of sleep per night, not one bad night (PubMed 21632481).

“A balding scalp holds a quantified amount more DHT.” We searched the FDA label and found the direction of the difference, but no quantified figure for how much more DHT a balding scalp holds than a non-balding scalp (DailyMed finasteride 1 mg label).

“The AUA guideline defines deficiency by a specific cutoff.” We searched the primary AUA text and found that the widely repeated claim about a specific total-testosterone cutoff in ng/dL could not be confirmed from the text retrieved (PubMed 29601923).

How to cite this page

Cite this page as: Real World Appeal. “Androgens and appearance: a glossary with a real number behind every term.” 2026-09-25. https://realworldappeal.com/blog/androgens-and-appearance-glossary

The bottom line

Androgen vocabulary can explain a lab result, a hair follicle, a receptor, or a voice change. It cannot tell you, by itself, how a stranger will read your face. The strongest facial result here points to prenatal timing, while adult circulating testosterone showed no facial-masculinity association in that study.

If a looksmaxxing thread is turning every number into a reason to panic, step back. Your face is not a hormone report, and your first impression is not a single trait. Use these figures to read claims more sharply, not to build a new source of compulsive checking.

Sources

• U.S. National Library of Medicine, DailyMed. FDA-approved prescribing information: testosterone · finasteride 1 mg · finasteride 5 mg · dutasteride
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• Bhasin S, Brito JP, Cunningham GR, et al. (2018). Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. The Journal of clinical endocrinology and metabolism, 103(5), 1715-1744. PubMed 29562364
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• Draelos ZD, Kyeremateng K & Squittieri N (2025). Reduction in Facial Sebum Production Following Treatment with Clascoterone Cream 1% in Patients with Acne Vulgaris: 12-Week Interim Analysis. Dermatology and therapy, 15(9), 2657-2666. PubMed 40682762
• Chouhan K, Kota RS, Kumar A, et al. (2019). Assessment of Safe Donor Zone of Scalp and Beard for Follicular Unit Extraction in Indian Men: A Study of 580 Cases. Journal of cutaneous and aesthetic surgery, 12(1), 31-35. PubMed 31057266
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