Boldenone undecylenate is an injectable veterinary steroid that exhibits strong anabolic and moderately androgenic properties. The undecylenate ester extends the activity of the drug greatly (the undecylenate ester is only one carbon atom longer than decanoate), so that injections need to be repeated only once every 3 or 4 weeks. The well-balanced anabolic and androgenic properties of this drug are greatly appreciated by athletes, who generally consider it to be a stronger, slightly more androgenic, alternative to Deca- Durabolin®. It is generally cheaper, and could replace Deca in most cycles without greatly changing the end result. Boldenone undecylenate is also commonly known as a drug capable of increasing red blood cell production, although there should be no confusion that this is an effect characteristic of nearly all anabolic/androgenic steroids.
Ciba reportedly patented boldenone as a synthetic anabolic steroid in 1949. During the 1950’s and ’60’s, the firm developed several experimental esters of the drug, and would later release a long-acting form of the agent (briefly) in the form of boldenone undecylenate. It would be sold under the brand name Parenabol, which likely referred to its characteristics as a parenteral (injectable) anabolic agent. Parenabol saw some clinical use during the late ’60’s and early ’70’s, mainly as a lean-tissue-preserving anabolic agent in cases of wasting, and for the retention of bone mass with osteoporosis. Boldenone undecylenate was a shortlived preparation on human medical markets, however, and would be discontinued globally before the end of the 1970’s. Squibb would ultimately be most famous for introducing this agent in the veterinary market, and would sell it under its now most famous trade name, Equipoise.
Side Effects (Estrogenic):
Boldenone is aromatized in the body to estradiol (estrogen). Elevated estrogen levels can cause side effects such as increased water retention, body fat gain, and gynecomastia. Boldenone is considered a mildly estrogenic steroid. Aromatization studies suggest that its rate of conversion to estradiol is roughly half that of testosterone. The tendency to develop noticeable estrogenic side effects with boldenone should be slightly higher than nandrolone, but much lower than with testosterone. Estrogenic side effects are usually not pronounced unless this drug is taken in doses above 200-400 mg per week. An anti-estrogen such as clomiphene citrate or tamoxifen citrate might be used to help mitigate these side effects, should they become present. One may alternately use an aromatase inhibitor like Arimidex® (anastrozole), although it is considerably more expensive, and may negatively affect blood lipids.
Side Effects (Androgenic):
Although classified as an anabolic steroid, androgenic side effects are still common with this substance, especially with higher doses. This may include bouts of oily skin, acne, and body/facial hair growth. Anabolic/androgenic steroids may also aggravate male pattern hair loss. Women are also warned of the potential virilizing effects of anabolic/androgenic steroids. These may include a deepening of the voice, menstrual irregularities, changes in skin texture, facial hair growth, and clitoral enlargement. Note that while boldenone does reduce to a more potent androgen (dihydroboldenone) via the 5-alpha reductase enzyme in androgen-responsive target tissues such as the skin, scalp, and prostate, its affinity to do so in the human body is extremely low. The relative androgenicity of boldenone is, therefore, not significantly affected by finasteride or dutasteride.