Boldenone is a 1-dehydro derivative of testosterone that has been sold as a veterinary preparation under the name Equipoise and is largely known by this name. The formation of a double bond in the 1,2 position changes the shape of the molecule slightly. This also changes the potency and characteristics of the molecule. Boldenone has a lower affinity than testosterone for the androgen receptor making it less potent on a mg for mg basis1.
This steroid can be converted to estrogen but less so than testosterone, in addition, boldenone is metabolized to 1,4 dienedione which is a potent aromatase inhibitor. Boldenone is converted by 5-alpha reductase to 1-testosterone, a more potent steroid as well as to the 5-beta isomer which is thought to be an inactive metabolite2,3. Binding to SHBG is much lower with boldenone than with testosterone meaning a larger free plasma concentration but a shorter half-life in plasma4. There is little to no binding to progesterone or glucocorticoid receptors and no real data on the interaction of boldenone with the different enzyme systems1.
The undecyclenate ester of boldenone was the ester marketed under the original trade name but the free base as well as other esters are available as underground preparations. On the street equipoise is considered erroneously to have the same activity as deca and is often substituted for deca in a stack. Dan Duchaine, if not the originator of this myth, at the very least promoted it in his book “Underground Steroid Handbook II”. If you look at the structure however, you can see that it is structurally identical to dianabol without the C-17 alkylation. Most people experience much less side effects with boldenone compared to methandrostenolone. This is due to the fact that boldenone converts to estradiol while methandrostenolone converts to methylestradiol. Methylestradiol is a much more potent and long lasting estrogen than plain estradiol. Since there is no C-17 alkylation, there is no liver toxicity associated with boldenone.
Boldenone is rumored to be very good at increasing red blood cell production. While all androgens stimulate erythropoiesis, there is no evidence in the scientific literature that boldenone is superior in producing this effect5,6,7,8. This increased RBC production may have an ergogenic effect by increasing athletic performance.
Boldenone undecyclenate is generally injected every four or five days but some people will inject every day while others will inject once per week. The longer half-life of the undecyclenate ester would dictate an injection frequency of every 10-14 days but there has been a trend towards more frequent dosing by AAS users even with drugs known to have long half-lives. Dosing is generally kept pretty low (300-500 mgs per week) however the low binding affinity would argue for doses twice that which would be taken with testosterone. The anabolic to androgenic ratios are favorable for boldenone however people do not consider boldenone to be a particularly potent steroid, possibly due to the low doses that are utilized. Also, boldenone does not cause much water retention so many people assume it is not working if they do not put on ten pounds in one week. Boldenone is said to cause an increase in vascularity. There is no mechanism to explain why boldenone would do this anymore than any other AAS.
1. Ojasoo T, Delettre J, Mornon JP, Turpin-VanDycke C, Raynaud JP: Towards the mapping of the progesterone and androgen receptors. J Steroid Biochem. 27(1-3):255-69, 1987
2. Schanzer W, Donike M: Metabolism of boldenone in man: gas chromatographic/mass spectrometric identification of urinary excreted metabolites and determination of excretion rates. Biol Mass Spectrom. Jan;21(1):3-16, 1992
3. Schanzer W: Metabolism of anabolic androgenic steroids. Clin Chem. Jul;42(7):1001-20, 1996
4. Saartok T, Dahlberg E, Gustafsson JA: Relative binding affinity of anabolic-androgenic steroids: comparison of the binding to the androgen receptors in skeletal muscle and in prostate, as well as to sex hormone-binding globulin. Endocrinology. Jun;114(6):2100-6, 1984
5. Gorshein D, Murphy S, Gardner FH. Comparative study on the erythropoietic effects of androgens and their mode of action. J Appl Physiol. 35(3):276-8, 1973
6. Paulo LG, Fink GD, Roh BL, Fisher JW. Effects of several androgens and steroid metabolites on erythropoietin production in the isolated perfused dog kidney. Blood. 43(1):39-47, 1974
7. Sanchez-Medal L, Gomez-Leal A, Duarte L, Guadalupe Rico M. Anabolic androgenic steroids in the treatment of acquired aplastic anemia. Blood. 34(3):283-300, 1969
8. Alexanian R. Erythropoietin and erythropoiesis in anemic man following androgens. Blood. 33(4):564-72, 1969
Adapted with permission from Seth Robert’s Anabolic Pharmacology, all rights reserved.