Like other AAS, boldenone is an agonist of the androgen receptor (AR).  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 metandienone , for androgen deficiency disorders. Boldenone acts similar to metandienone with fewer adverse androgenic effects. [ medical citation needed ] Although commonly compared to nandrolone , boldenone lacks progesterone receptor interaction and associated progestogenic side effects.
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.