Boldenone Cypionate

Boldenone cypionate is boldenone with a cypionate ester attached. Boldenone itself is testosterone with an extra double bond between the first and second carbon atoms, chemically 1-dehydrotestosterone. The compound is better known as the undecylenate, which comes from veterinary medicine under the brand name Equipoise.

The cypionate is the shorter of the two esters. The active compound in the body is the same, it is simply released faster from the depot in the muscle. In the range, boldenone cypionate comes as an oily injectable solution at 200 mg/ml.

This information is for research and educational purposes only. No medical advice.

Boldenone binds to the androgen receptor and, like other anabolic steroids, increases protein synthesis and nitrogen retention in muscle. Its signature is a marked stimulation of blood formation: the share of red blood cells (hematocrit) rises. This is often linked to more endurance and a stronger pump, but it also thickens the blood.

The extra double bond slows down aromatase. Boldenone is therefore converted to estrogen less than testosterone, in practice about half is the figure usually quoted. That does not make it free of estrogenic effects. The 5-alpha reduced form of boldenone is dihydroboldenone (DHB, 1-testosterone), which has its own entry as a separate product.

Gains on boldenone are considered slow and fairly moderate. Many users also report a clearly increased appetite. Solid human data on the profile are scarce, so the picture relies on general steroid pharmacology and animal data.

Both products deliver the same active compound, only the ester differs. The undecylenate is a very long ester with a half-life of about 14 days. The cypionate is shorter: for testosterone the prescribing information gives about 8 days, for boldenone cypionate itself there is no human measurement.

• Blood levels: with the cypionate, levels rise faster and also drop faster after stopping.
• Active content: the shorter ester weighs less. By calculation, 1 mg of cypionate holds about 0.70 mg of boldenone, 1 mg of undecylenate about 0.63 mg.
• Frequency: two injections per week keep levels stable, with the undecylenate one is often enough.
• Build-up: boldenone still builds slowly, the cypionate only shortens the time until blood levels plateau.

Boldenone cypionate is usually injected intramuscularly, into the glutes, thigh or shoulder. With long esters subcutaneous use is possible too, but no more than about 0.5 ml should go into one spot. At 0.75 to 1.5 ml per dose, intramuscular is therefore usually more practical.

• Draw up with a thicker needle, inject with a thinner one (23G to 25G).
• Disinfect the rubber stopper and the injection site with alcohol first, use every needle only once.
• Inject slowly and rotate sites regularly.
• Never share a vial. Case reports of abscesses and hepatitis almost always trace back to non-sterile technique or shared vials.

Boldenone is mainly a veterinary compound. A review of testosterone, boldenone and nandrolone in horses describes decades of use for muscle building, while noting that the evidence on its effects is thin even in animals (Dirikolu, J Vet Pharmacol Ther 2023). There are no controlled human studies on either the undecylenate or the cypionate.

The general pharmacology of anabolic steroids is well described: binding to the androgen receptor, the role of aromatase and 5-alpha reductase and the typical side effects (Kicman, Br J Pharmacol 2008). For athletes, a review summarizes effects on strength, body composition, lipids, hormones and the liver (Hartgens and Kuipers, Sports Med 2004).

Animal data show that the effects reach beyond muscle. In a rat study with boldenone undecylenate over 8 weeks, inflammatory markers rose, thyroid hormones fell and TSH increased (El Deib, Int Immunopharmacol 2021). These are high doses in animals and not directly transferable, but they are a reason to keep an eye on blood work.

• Hematocrit: the key issue with boldenone. Thicker blood raises the risk of thrombosis and strains the heart. Measure regularly.
• Blood pressure: rises in many users, partly because of the higher hematocrit.
• Estrogen: weaker than with testosterone, yet water retention or gynecomastia are still possible in predisposed users.
• Lipids: HDL drops and the lipid profile shifts unfavorably.
• Natural production: is suppressed. Without a testosterone base, low libido and low drive are likely. PCT becomes a topic afterwards.
• Androgenic: acne and hair loss in predisposed users.
• Other: strong appetite, at higher doses some report restlessness or anxiety.

Boldenone is on the WADA prohibited list and remains detectable in testing long after the last injection.

Store the oily solution at room temperature and away from light, ideally in the original box. Do not put it in the fridge: in the cold the compound can crystallize. If crystals do form, warm the vial in your hand or in warm water and swirl it until the solution is clear again. Keep out of reach of children.