Testosterone Enanthate

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Cat Number

API0231628

CAS Number

315-37-7

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Product Detail Description Scientific Support Customer Q&A

CAS Number

315-37-7

EINECS

206-253-5

Storage

Store at room temperature

Synonyms

Androtardyl; Testosterone heptanoate; Testinon; Testosterone enantate; Everone; Testosterone heptylate

Molecular Formula

C26H40O3

Molecular Weight

400.6

Smiles

CCCCCCC(=O)O[C@H]1CC[C@@H]2[C@@]1(CC[C@H]3[C@H]2CCC4=CC(=O)CC[C@]34C)C

Appearance

White to creamy white crystalline powder

Melting Point

34-39℃

Boiling Point

503.9℃ at 760 mmHg

Relative Density

1.0562 (Predicted)

General Description

Testosterone enanthate is a long-acting ester of testosterone, administered via deep intramuscular injection for androgen replacement therapy. It has a duration of action of 2-4 weeks, making it more convenient than unesterified testosterone or testosterone propionate.

Mechanism of Action

After intramuscular injection, esterases in plasma and tissues slowly cleave the enanthate side chain, releasing free testosterone. Testosterone binds to androgen receptors in target tissues, promoting male sexual development, secondary sex characteristics, nitrogen retention, and erythropoiesis. It also exerts negative feedback on the hypothalamic-pituitary-gonadal axis, suppressing LH and FSH secretion.

Application

Testosterone enanthate is indicated for males with primary or secondary hypogonadism (congenital or acquired) and for delayed puberty in select boys. It is also used off-label for gender-affirming hormone therapy in transgender men. Dosing typically ranges from 50-400 mg every 2-4 weeks, titrated to achieve normal serum testosterone levels.

In the PRIBS study, 27 boys aged 14–16 years with delayed puberty were randomized to testosterone enanthate (75 mg i.m./month) or testosterone undecanoate (250 mg i.m./3 months). After 12 months, 12/14 (86%) of the undecanoate group and 12/12 (100%) of the enanthate group achieved testicular enlargement ≥8 ml (Fisher’s exact two‑sided P=0.483). The study was underpowered (25%), so no evidence‑based conclusion can be drawn, but clinical data support similar efficacy. Both treatments were well tolerated. The authors note that undecanoate is a convenient alternative to enanthate for pubertal induction.

Fig. 1 Flowchart of patient recruitment in the Pubertal Replacement in Boys Study. (Österbrand M, et al., 2023)

References

Österbrand M, et al. Pharmacological treatment for pubertal progression in boys with delayed or slow progression of puberty: A small-scale randomized study with testosterone enanthate and testosterone undecanoate treatment. Front Endocrinol (Lausanne). 2023;14:1158219.

Does Testosterone Enanthate require protection from light during storage?

Yes, it is photosensitive. Light exposure can cause photodegradation and isomerization. Store in light-resistant containers, preferably amber glass.

What is the recommended storage temperature for Testosterone Enanthate?

Store at controlled room temperature (15-25°C). Avoid excessive heat above 30°C, which can soften the oily liquid and accelerate ester hydrolysis.

Is Testosterone Enanthate stable in oil-based injectable formulations?

Yes, it shows excellent stability when dissolved in sesame or cottonseed oil with preservatives (e.g., benzyl alcohol). We provide compatibility data for various oil vehicles.

How is the impurity testosterone (free alcohol) monitored during stability?

This primary hydrolysis product is specifically quantified using a stability-indicating HPLC method, ensuring it remains below USP/EP limits.