Boldenone (INN, BAN), also known as Δ1-testosterone, 1-dihydrotestosterone, or androsta-1,4-dien-3-one-17β-ol (train name Equipoise) is a long-acting injectable anabolic agent for horses, supplied in a vial providing 50 mg boldenone undecylenate per mL in sesame oil with 3% (w/v) benzyl alcohol as a preservative. The activity of boldenone is mainly anabolic, with a low androgenic potency. Boldenone will increase nitrogen retention, protein synthesis increases appetite and stimulates the release of erythropoietin in the kidneys. Boldenone was synthesized in an attempt to create a long-acting injectable methandrostenolone (Dianabol), for androgen deficiency disorders. Boldenone acts similar to methandrostenolone with fewer adverse androgenic effects. Although commonly compared to nandrolone, boldenone lacks progesterone receptor interaction and all the associated progestogenic side effects. Equipoise (Boldenone Undecylenate Injection) is recommended as an aid for treating debilitated horses when an improvement in weight, haircoat or general physical condition is desired. Debilitation often follows disease or may occur following overwork and overexertion. Boldenone improves the general state of debilitated horses, thus aiding in correcting weight losses and improving appetite. It is not a substitute for a well-balanced diet. Optimal results can be expected only when good management and feeding practices are utilized. Boldenone should be considered only as adjunctive therapy to other specific and supportive therapy for diseases, surgical cases, and traumatic injuries.

Androstenedione (Δ4-Androstenedione, 4-androstene-3,17-dione or 17-ketotestosterone) is an endogenous androgen steroid hormone and intermediate in the biosynthesis of testosterone from dehydroepiandrosterone (DHEA). In turn, Androstenedione is also a precursor of dihydrotestosterone (DHT), estrogens such as estradiol and estrone, and the neurosteroid 3α-androstanediol. Androstenedione is used to increase the production of the hormone testosterone to enhance athletic performance, increase energy, keep red blood cells healthy, enhance recovery and growth from exercise, and increase sexual desire and performance. Androstenedione has been shown to increase serum testosterone levels over an eight-hour period in men when taken as a single oral dose of 300 mg per day, but a dose of 100 mg had no significant effect on serum testosterone. However, serum levels of estradiol increased following both the 100 mg and 300 mg doses. The study also reported that the serum level of estrogens and testosterone produced varied widely among individuals. Androstenedione is currently used as a nutritional supplement to grow bigger muscles and stronger bones. This implies that androstenedione may have anabolic properties. Even though it has not been convincingly demonstrated yet that androstenedione is an anabolic steroid, its anabolic properties are likely based on its proven ability to increase testosterone levels. The role of testosterone in building stronger muscles and bones is widely accepted. Thus, high doses of testosterone-boosting drugs combined with strength training have been shown to increase muscle size and strength even in normal young men. This confirms what thousands of athletes who take anabolic steroids have known for decades. Yet androstenedione is different from testosterone-boosting drugs in a number of important aspects. To begin with, androstenedione is a naturally occurring substance that is produced by the body itself. In contrast to synthetic anabolic steroids, androstenedione is right at home in the human body, and perfectly complements the complex hormonal network in the body. Information about possible side effects and risks of androstenedione is very limited. Also, recent studies show that the drug's actions don't support manufacturer's claims. While a few individuals have shown increased levels of testosterone, most failed to achieve increases in blood testosterone levels. Initial medical research has raised concerns about this supplement's safety. Doctors worry that androstenedione may increase the risk of heart disease or liver cancer. In addition, research also associates androstenedione use with increases in estradiol, a female estrogen.

This compound belongs to the class of organic compounds known as androgens and derivatives. These are 3-hydroxylated C19 steroid hormones. They are known to favor the development of masculine characteristics. They also show profound effects on scalp and body hair in humans. The value of Δ5-diol as a radiation countermeasure is based mainly on its stimulation of production of white blood cells and platelets. Androstenediol used by the body to make testosterone and estrogen. There is some concern that androstenediol might increase the risk of coronary heart disease. There is also developing evidence that androstenediol might help prostate cancer cells grow. Taking androstenediol along with estrogen and testosterone pills might cause too much estrogen or testosterone in the body.

Bolasterone (7α, 17α‐dimethyltestosterone) is an anabolic steroid. It is able to activate androgen receptor. Despite being a testosterone derivative, bolasterone is also much more anabolic than androgenic in nature. At a given therapeutic level, it is much less likely to cause androgenic/virilizing side effects. he drug was developed by Upjohn, and sold in the U.S. during the 1960’s under the Myagen brand name. It was mainly indicated for the treatment of advanced breast cancer in women, although the agent was also investigated for its stimulatory effect on blood cells and its general anabolic (lean-tissue sparing) activity. Bolasterone was ultimately a short-lived drug, disappearing from the U.S. market shortly after its release.

Testosterone is a steroid sex hormone found in both men and women. In men, testosterone is produced primarily by the Leydig (interstitial) cells of the testes when stimulated by luteinizing hormone (LH). It functions to stimulate spermatogenesis, promote physical and functional maturation of spermatozoa, maintain accessory organs of the male reproductive tract, support development of secondary sexual characteristics, stimulate growth and metabolism throughout the body and influence brain development by stimulating sexual behaviors and sexual drive. In women, testosterone is produced by the ovaries (25%), adrenals (25%) and via peripheral conversion from androstenedione (50%). Testerone in women functions to maintain libido and general wellbeing. Testosterone exerts a negative feedback mechanism on pituitary release of LH and follicle-stimulating hormone (FSH). Testosterone may be further converted to dihydrotestosterone or estradiol depending on the tissue. The effects of testosterone in humans and other vertebrates occur by way of two main mechanisms: by activation of the androgen receptor (directly or as DHT), and by conversion to estradiol and activation of certain estrogen receptors. Free testosterone (T) is transported into the cytoplasm of target tissue cells, where it can bind to the androgen receptor, or can be reduced to 5α-dihydrotestosterone (DHT) by the cytoplasmic enzyme 5α-reductase. DHT binds to the same androgen receptor even more strongly than T, so that its androgenic potency is about 2.5 times that of T. The T-receptor or DHT-receptor complex undergoes a structural change that allows it to move into the cell nucleus and bind directly to specific nucleotide sequences of the chromosomal DNA. The areas of binding are called hormone response elements (HREs), and influence transcriptional activity of certain genes, producing the androgen effects. Testosterone is used as hormone replacement or substitution of diminished or absent endogenous testosterone. Use in males: For management of congenital or acquired hypogonadism, hypogonadism associated with HIV infection, and male climacteric (andopause). Use in females: For palliative treatment of androgen-responsive, advanced, inoperable, metastatis (skeletal) carcinoma of the breast in women who are 1-5 years postmenopausal; testosterone esters may be used in combination with estrogens in the management of moderate to severe vasomotor symptoms associated with menopause in women who do not respond to adequately to estrogen therapy alone.

Dromostanolone Propionate (known by the brand names Masteron and Drolban) was invented by Syntex in 1959. About 10 years later it was released on the American market by Lilly as brand name Drolban. The drug was first approved in the USA for use as a treatment of female breast cancer. However, the profile of side-effects included pronouncement of male characteristics in women and when more effective breast cancer treatments came to market drostanolone was gradually phased out. No longer used clinically dromostanolone propionate became very popular in the bodybuilding community. Today dromostanolone propionate remains on the list of approved medications, but it is not being manufactured or sold by pharmaceutical companies. It is still produced illegally by underground labs for use in the bodybuilding community.

Methenolone (also known as primobolan) was described in 1960. Squibb Company began producing injectable drug in 1962. Methenolone originally was prescribed in case of muscle loss after operations, infections, long-term illnesses, aggressive therapy with corticoids or malnutrition, and in some cases it was used to treat osteoporosis and breast cancer. Methenolone was commonly used to promote weight gain in infants, weighing less than normal, without any side effects. Methenolone is an anabolic steroid, modification of dihydrotestosterone (DHT) with weak androgenic activity and a moderate anabolic effect. A notable trait of methenolone is that it can firmly bind to androgen receptors, stronger than testosterone. Adult doses for the treatment of aplastic anemia are usually in a range of 1–3 mg/kg per day. Adverse side effects include fluid and electrolyte retention, hypercalcaemia, increased bone growth and skeletal weight. In men, additional side priapism, azoospermia, hirsutism, male pattern baldness, acne andoedema. In women, side effects include virilization, amenorrhoea, menstrual irregularities, suppressed lactation, and increased libido. In children, side effects may include virilization symptoms. Metenolone may enhance effects of antidiabetics, ciclosporin, levothyroxine, warfarin. Resistance to the effects of neuromuscular blockers may occur, and metenolone also has the potential to interfere with glucose tolerance and thyroidfunction tests. Metenolone enanthate (methenolone enanthate) is an ester derivative of methenolone sold commonly under the brand names Primobolan (tablet form) orPrimobolan Depot (injectable). When it interacts with the aromatase enzyme it does not form any estrogens. It is used by people who are very susceptible to estrogenic side effects, having lowerestrogenic properties than nandrolone. This trait makes primobolan to be a good fat burner. Primobolan does not convert into estradiol. As an anabolic steroid, the use of metenolone is banned from use in sports governed by the World Anti-Doping Agency. Belarusian shot putter Nadzeya Ostapchuk was stripped of her gold medal after testing positive for metenolone at the London 2012 Olympic Games. She has been excluded from future IOC events. The NBA and NBPA also banned the use of methenolone under the Anti-Drug Program. In February 2013, Hedo Türkoğlu of the Orlando Magic was suspended for 20 games without pay by the league after testing positive for methenolone. In December 2013, Natalia Volgina was stripped of her 2013 Old Mutual Two Oceans Marathon title and received a two-year competition ban, subsequent to a final guilty verdict for using the steroid Metenolone.