Finasteride is a synthetic 4-azasteroid compound. This drug is a competitive and specific inhibitor of Type II 5a-reductase, an intracellular enzyme that converts the androgen testosterone into 5α-dihydrotestosterone (DHT). Two distinct isozymes are found in mice, rats, monkeys, and humans: Type I and II. Each of these isozymes is differentially expressed in tissues and developmental stages. In humans, Type I 5a-reductase is predominant in the sebaceous glands of most regions of skin, including scalp, and liver. Type I 5a-reductase is responsible for approximately one-third of circulating DHT. The Type II 5a-reductase isozyme is primarily found in prostate, seminal vesicles, epididymides, and hair follicles as well as liver, and is responsible for two-thirds of circulating DHT. Although finasteride is 100-fold more selective for type II 5a-reductase than for the type I isoenzyme, chronic treatment with this drug may have some effect on type I 5a-reductase. Finasteride is used for the treatment of symptomatic benign prostatic hyperplasia (BPH) in men with an enlarged prostate to: Improve symptoms, reduce the risk of acute urinary retention, reduce the risk of the need for surgery including transurethral resection of the prostate. Also used for the stimulation of regrowth of hair in men with mild to moderate androgenetic alopecia (male pattern alopecia, hereditary alopecia, common male baldness). Finasteride is sold under the brand names Proscar and Propecia among others.

3-Oxo-4-aza-5α-androstane-17β-(N-t-butylcarboxamide) (or dihydrofinasteride) is the reduced product of Finasteride. Finasteride acts as an alternate substrate for steroid 5α-reductase and is initially bound in an extremely stable enzyme-bound NADP-dihydrofinasteride adduct which is ultimately processed to dihydrofinasteride. Dihydrofinasteride acts as a selective inhibitor of steroid 5α-reductase type 1.

Coprostanone is a metabolite of cholesterol. The conversion of cholesterol into coprostanol by intestinal microorganisms has been reported to occur by means of two different pathways. One pathway involves the intermediate formation of delta4-cholelestenone and coprostanone. In the other pathway, cholesterol is transformed into coprostanol by the direct reduction of the delta5 double bond. Coprostanone concentration is used as a fecal sterol biomarker in different investigations. For example, to determine of fecal sterols following a diet with and without plant sterols, to assess if faecal steroid excretion in humans is affected by calcium supplementation and other investigations.

Sphinganine is a naturally occurring, skin-identical sphingoid base, a representative of the class of amino alcohols, or long chain bases (LCBs). Sphinganine is a blocker postlysosomal cholesterol transport by inhibition of low-density lipoprotein-induced esterification of cholesterol and cause unesterified cholesterol to accumulate in perinuclear vesicles. It has been suggested the possibility that endogenous sphinganine may inhibit cholesterol transport in Niemann-Pick Type C (NPC) disease. Sphinganine is a potent inhibitor of 5-α-reductase type I that prevents the conversion of testosterone to dihydrotestosterone, a key factor of androgenetic male baldness. As a cosmetic ingredient, sphinganine is well suited as a topical alternative for the improvement of scalp health and hair quality and anti-hair loss application. Sphinganine promotes differentiation and ceramide production in keratinocytes. Free sphinganine may serve as a dermatological and cosmetic agent by enhancing formation and maintenance of an intact epidermal lipid barrier, with beneficial effects for skin and hair care applications.