Equipoise — boldenone undecylenate

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.

Brand name Equipoise, Boldenone undecylenate, Parenabol, Ganabol, Boldenona, Boldegan, Ultragan, Boldebal-H, Pace, Venbol
Androgenic 50
Anabolic 100
Standard Testosterone
Chemical Names 1.4-androstadiene-3-one,17beta-ol
Estrogenic Activity low
Progestational Activity no data available (low)

Boldenone Undecylenate History

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.

In the veterinary market, boldenone undecylenate is most commonly applied to horses, although in many regions it is indicated for use in other animals as well. It generally exhibits a pronounced effect on lean bodyweight, appetite, and general disposition of the animal. The Equipoise brand was sold under the Squibb label until 1985, when Solvay acquired Squibb’s U.S. animal health business. Equipoise would be sold under the Solvay label for the next several years, until Wyeth finally acquired the animal health division of Solvay in 1995. The division was formed into Fort Dodge Animal Health, which continues to market Equipoise in the U.S. and certain markets abroad today. Many other generic and brand name forms of boldenone undecylenate exist in numerous international drug markets, owing to the fact that any patents on boldenone undecylenate have long since expired.

How is Boldenone Undecylenate Supplied

Boldenone undecylenate is widely available in veterinary drug markets. Composition and dosage may vary by country and manufacturer; the majority of products are supplied as multi-dose glass vials containing an oily solution; usually carrying 25 mg/ml or 50 mg/ml of steroid.

Structural Characteristics of Boldenone Undecylenate

Boldenone is a modified form of testosterone. It differs by the introduction of a double bond between carbons 1 and 2, which reduces its relative estrogenicity and androgenicity. Equipoise contains boldenone modified with the addition of carboxylic acid ester (undecylenoic acid) at the 17-beta hydroxyl group. Esterified steroids are less polar than free steroids, and are absorbed more slowly from the area of injection. Once in the bloodstream, the ester is removed to yield free (active) boldenone. Esterified steroids are designed to prolong the window of therapeutic effect following administration, allowing for a less frequent injection schedule compared to injections of free (unesterified) steroid. Boldenone undecylenate is designed to provide a peak release of boldenone within a few days after injection, and sustain hormone release for approximately 21-28 days.

It is interesting to note that structurally boldenone and methandrostenolone (Dianabol) are almost identical. In the case of boldenone (as applied here), the compound uses a 17-beta ester (undecylenate) to facilitate administration, while methandrostenolone accomplishes this with the use of a 17-alpha alkyl group. Aside from this, the molecules are the same. Of course they act quite differently in the body, which goes to show that the 17-methylation affects more than just the oral efficacy of an anabolic/androgenic steroid.

Boldenone Undecylenate 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 antiestrogen 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.

Boldenone Undecylenate 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.

Boldenone Undecylenate Side Effects (Hepatotoxicity)

Boldenone is not c-17 alpha alkylated, and not known to have hepatotoxic effects. Liver toxicity is unlikely.

Boldenone Undecylenate Side Effects (Cardiovascular)

Anabolic/androgenic steroids can have deleterious effects on serum cholesterol. This includes a tendency to reduce HDL (good) cholesterol values and increase LDL (bad) cholesterol values, which may shift the HDL to LDL balance in a direction that favors greater risk of arteriosclerosis. The relative impact of an anabolic/androgenic steroid on serum lipids is dependant on the dose, route of administration (oral vs. injectable), type of steroid (aromatizable or non-aromatizable), and level of resistance to hepatic metabolism. Anabolic/androgenic steroids may also adversely affect blood pressure and triglycerides, reduce endothelial relaxation, and support left ventricular hypertrophy, all potentially increasing the risk of cardiovascular disease and myocardial infarction. Boldenone is likely to have a less dramatic impact on cardiovascular risk factors than synthetic oral anabolic steroids. This is due in part to its openness to metabolism by the liver, which allows it to have less effect on the hepatic management of cholesterol. The aromatization of boldenone to estradiol may also help to mitigate the negative effects of androgens on serum lipids.

To help reduce cardiovascular strain it is advised to maintain an active cardiovascular exercise program and minimize the intake of saturated fats, cholesterol, and simple carbohydrates at all times during active AAS administration. Supplementing with fish oils (4 grams per day) and a natural cholesterol/antioxidant formula such as Lipid Stabil or a product with comparable ingredients is also recommended.

Boldenone Undecylenate Side Effects (Testosterone Suppression)

All anabolic/androgenic steroids when taken in doses sufficient to promote muscle gain are expected to suppress endogenous testosterone production. Without the intervention of testosterone-stimulating substances, testosterone levels should return to normal within 1-4 months of drug secession. Note that prolonged hypogonadotrophic hypogonadism can develop secondary to steroid abuse, necessitating medical intervention.

Boldenone Undecylenate Administration (Men)

Although it stays active for a much longer time, boldenone undecylenate is injected at least weekly for physique- or performance-enhancing purposes. It is most commonly used at a dosage of 200-400 mg (4-8ml,50 mg version) per week. The dosage schedule can be further divided to reduce the volume of each injection if necessary, perhaps administering the drug two to three times per week. One should also take caution to rotate injection sites regularly, so as to avoid irritation or infection.

Not a rapid mass builder, boldenone undecylenate instead provides a slow but steady gain of strength and quality muscle mass. The positive effects of this drug become most apparent when it is used for longer cycles, usually lasting 8 weeks or more in duration. The muscle gained should also not be the smooth bulk associated with testosterone, but more defined and solid. Since water bloat is not contributing greatly to the diameter of the muscle, more of the visible size gained on a cycle of boldenone undecylenate should be retained after the drug has been discontinued.

Boldenone undecylenate is a very versatile drug, and can be combined with a number of other agents depending on the desired result. For mass, it is commonly stacked with an injectable testosterone such as enanthate or cypionate. This should produce strong gains in muscle size and strength, without the same intensity of side effects of using testosterone (at a higher dose) alone. During a cutting phase, muscle hardness and density can be greatly improved when combining boldenone undecylenate with a non-aromatizable steroid such as trenbolone acetate or methenolone enanthate. Oral c-17 alpha alkylated agents such as fluoxymesterone or stanozolol may also be used, but will present some level of hepatotoxicity. For some, even the low buildup of estrogen associated with this compound is enough to relegate its use to bulking cycles only.

Boldenone Undecylenate Administration (Women)

When used for physique- or performance-enhancing purposes, women take much lower doses of boldenone undecylenate than men, typically 50-75 mg per week. Women should take caution with the slow-acting characteristics of this preparation, which make blood levels difficult to control and slow to decline should virilization symptoms become present.

Boldenone Undecylenate Availability

Boldenone undecylenate remains widely available as a veterinary drug product. It is produced mainly in the Americas, consistently at a dosage of 25 mg/mL or 50 mg/mL. A small number of preparations are made at a higher dosage (typically 200 mg/mL), mainly by companies in less regulated markets of Asia where supply is often dictated by black market demand. In reviewing some of the more popular products and changes on the global pharmaceutical market, we have made the following observations.

Brand name Equipoise is no longer available in Canada. This product was formerly manufactured by Wyeth Animal Health, which following a series of mergers is now part of Pfizer. The Equipoise product was never manufactured under the Pfizer label.

Equipoise is produced in the United States by the Fort Dodge Company. The Fort Dodge products are sold readily in Mexico, and afterwards smuggled back into the U.S. Legitimate vials are made of clear glass, and carry a label with a shiny metallic surface on the under side. Fakes are very abundant of this item.

Ganabol, which is produced in a number of South American countries, is still a popular brand in international commerce. It is seen in two strengths (25 mg/mL and 50 mg/mL) and in five sizes (10, 50, 100, 250, and 500 mL). There have been numerous fakes of this product in the past, so be careful when shopping.

The Legacy brand name product from Tecnoquimicas in Argentina seems to be reaching the U.S. as of late, at least in small volume. This product carries 50 mg/mL of steroid in a 50 mL vial. At this time the Legacy product is very low on the radar, and probably can be trusted when located.

The brands Boldenona and Boldegan from Gen-Far are also popular in South America. These are low-dose (50 mg/mL) preparations. Like Ganabol, they come in a variety of vial sizes. Counterfeits do not appear to be a big issue at this time.

Boldenone is produced by Swiss Remedies and available across Europe. Due to numerous fakes of this product, Swiss Remedies offers a convenient online product checker.

Magnus Pharmaceuticals makes the product Boldenone 250 primarily for the EU and UK markets. Due to fake products appearing on the market, Magnus offers an online checker that lets steroid users verify their product originality.

Bodybuilders reference

Boldenone is available as a veterinary steroid under various trade names and was commonly refereed to as EQ by athletes polled. However, the quality is normally quite high due to its use in million dollar race horses. Boldenone was reported as one of the safest and most effective anabolic / androgenic injectable steroids used by both power lifters and bodybuilders. This drug brought slow but continuous muscle mass and strength gains over a prolonged period. Gains were mostly of a high quality lean mass nature and were maintained for several weeks after use was discontinued. Improved pumps and vascularity were normal are common attributes while low aromatization brought an improved hardness to users musculature.

Males normally reported a dosage range of 150-500mg weekly total, usually utilizing an every other day (EOD) injection schedule. Women made excellent progress with dosages of 50-150mg total weekly with a 1-2 injections weekly schedule. In this dose range, women seldom reported virilizing side effects. Most experienced an elevate libido (cool) with few other negative side effects reported. But in some cases, increased hair growth on face and legs were noted. This was usually due to higher dosages however and predominantly limited to existing hair (not new hair growth).

Due to Boldenone’s reported "non-toxic to the liver" structure, most users experienced great gains with none or few negative side effects. The appetite and red blood cell production stimulating effects of Equipoise marked this drug as a standard for those who sought few negative side effects with quality muscle mass gains. Obviously with increased red blood cell count an increase in oxygen transport was also realized, as was improved nutrient transport.

Due to a double carbon bond between carbons one and two, boldenone experiences only slight DHT conversion by the 5-alfa-reductase enzyme and is fairly resistant to aromatization to estrogens.

Male athletes commonly stacked Boldenone with testosterone and/or Anadrol-50 for mass and strength cycles. Pre-contest cycles utilizing this drug often included Trenbolones, Winstrol, and anti-estrogens to create the ultra hard and vascular look.

Personal experiences with Boldenone have resulted in very high quality lean tissue and freaky vascularity. This quite beneficial from a competitive appearance stand-point but long term use resulted in an unfavorable CBC result. I believe my error was in protocol length.

Anabolic Steroid Guide reference

Today, the substance boldenone undecylenate can only be found in steroids for veterinary medicine. The American Equipoise is for horses; the Columbian Ganabol is used for cattle; and the German Vebonol for dogs. Athletes do not care, which shows the enormous popularity and far reaching application of these steroid compounds. Boldenone undecylenate is also very effective in humans and offers the athlete interesting characteristics which other steroids simply do not have.

Equipoise has a relatively high anabolic effect which is usually connected with a moderately distinct androgenic component. For this reason, Equipoise is not the steroid that will cause enormous gains in strength and muscle mass in the shortest time. Equipoise has a very favorable effect on the organism's nitrogen balance so that the main effect consists of a distinctly increased protein synthesis in the muscle cell. The resulting gain in body weight consists of a solid quality increase of the muscles which occurs slowly and evenly. The high quality is caused by low water retention of the substance. An additional advantage is that Equipoise aromatizes only slightly, thus making it an effective drug to use when preparing for competitions. Athletes who are dieting combine Equipoise with Winstrol Depot and report a dramatic increase in muscle hardness. Together with a sufficiently high supply of calories and protein this combination offers its users a large increase in strength and a rapid gain in quality muscles. Many will notice that Equipoise stimulates the appetite. The advantages achieved can usually be wellmaintained over several weeks after use of the compound is discontinued. Equipoise also stimulates the erythropoiesis which is manifested by improved development and the formation of red blood cells. Bodybuilders thus experience an improved pump effect during workout and an improved vascularity For most male athletes the weekly dosage is usually 150-300 mg. Often since only the 25 mg version can be found, frequent or very voluminous injections are necessary. For most athletes 50 mg (corresponding to a 2 ml injection) taken every second day is sufficient. Advanced and ambitious bodybuilders usually take higher doses (50 mg daily) and achieve dramatic results. Women also usually respond well to Equipoise and with 50-100 mg/week they gain good muscles with a low water retention.

A dosage in this range is usually well tolerated. Higher dosages can cause virilization symptoms such as deep voice, increased production of the sebaccous gland and acne, increased libido and in some cases increased hair growth on the face and legs. Men have few problems with Equipoise. Since water and salt retentions are low, the blood pressure usually does not increase. Acne, gynecomastia, and increased aggressiveness occur only in rare instances. The feared "steroid fever," which can occur when using veterinary steroids, is rare with Equipoise since the product by Squibb is highly sterile and pure. Those who experience flu-like symptoms when they begin taking the compound should reduce the dosage for a short time. The price on the black market for a 10 ml vial is usu-ally around $90. The 50 ml vial is usually around $250.

Newbies Research Guide reference

Equipoise, or boldenone undecylenate, is a favorite veterinary steroid of many athletes. Its effects are strongly anabolic, and only moderately androgenic. By itself, Equipoise will provide a steady and consistent gain in mass and strength. However, best results are achieved when Equipoise is used in conjunction with other steroids. For mass, Equipoise stacks exceptionally well with Anadrol(oxymetholone), Dianabol (methandrostenlone), or an injectable testosterone like Sustanon 250. Equipoise is also highly effective for contest preparation since it aromatizes very poorly. Muslce hardness and density can be greatly improved when Equipoise is combined with Parabolan(trenbolone hexahydrobencylcarbonate), Halotestin(fluoxymesterone), or Winstrol(stanozolol). Average dosages of Equipoise are 200-400 mg per week. Injections are usually taken every other day. Since Equipoise is only available in a 25 or 50 mg/ml version, voluminous injections may become a problem. If high volume injections are made too frequently to the same injection site, an oil abscess may form. An oil abscess will often dissipate on its own, but in extreme instances, a doctor will need to drain it. Therefore, athletes should take caution and rotate injection sites. Equipoise is not readily available on the US black market, but it can be found. One of the more popular versions is Ganabol from Laboratorios V.M. in Middle and South America. It is mostly seen in 50 ml vials, but is also available in 10, 100, and 250 ml versions. Ganabol comes in a brown glass vial with a green label. 50 mg/ml versions will have a large “50” on the label. There are no counterfeits of Ganabol. The World Anabolic Review estimates the price of Ganabol to be $8 per ml. This price was probably overestimated. A more typical price is about $4-$6 per ml.


Wlliam Llewellyn (2011) - Anabolics
L. Rea (2002) - Chemical Muscle Enhancement Bodybuilders Desk Reference
Anabolic Steroid Guide
Newbies Research Guide

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