Synovex

What is Synovex?

• Brand name: Synovex (various formulations: Synovex-S, Synovex-H, Synovex-C).

• Type: Veterinary growth-promoting implant used in cattle.

• Composition: Each pellet implant typically contains a mixture of:

  • Estradiol benzoate (estrogen)

  • Testosterone propionate or Trenbolone acetate depending on the version

• It’s a cattle implant, not a human-approved drug.

• Examples:

  • Synovex-S: 200 mg testosterone propionate + 20 mg estradiol benzoate

  • Synovex-H: 200 mg testosterone propionate + 20 mg estradiol benzoate (for heifers)

  • Synovex-C: 100 mg testosterone propionate + 10 mg estradiol benzoate (for calves)

Some later Synovex products replaced testosterone with trenbolone acetate plus estradiol (similar to Revalor).

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Benefits

• Designed to improve feed efficiency, weight gain, and muscle deposition in cattle.

• Increases nitrogen retention, appetite, and overall growth.

• The estrogenic part promotes growth hormone/IGF axis; the androgenic part adds anabolic effect.

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Side Effects (in humans, theoretical)

• Estrogenic: gynecomastia, water retention, fat gain.

• Androgenic (from testosterone): acne, oily skin, hair loss.

• Suppression of natural hormones if used.

• Cardiovascular: lipid profile changes.

• In animals, side effects are not a concern because it’s used for fattening before slaughter, not long-term health.

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Pros and Cons

Pros (for cattle):

• Very effective growth promoter.

• Easy slow-release implant in the ear.

Cons (for humans):

• Not intended or approved for human use.

• Contains estrogen, so side effects are mixed androgenic/estrogenic.

• The dosage and release profile are not standardized for humans.

• Legally, tampering with or extracting these substances for human use violates regulations.

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Dosage & Frequency

• In cattle: one implant pellet in the ear at certain intervals (lasts about 100–120 days).

• In humans: no established safe dosage—any use is illicit and unpredictable.

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Half-Life & Detection Time

• Testosterone propionate half-life: ~2 days.

• Estradiol benzoate half-life: ~2–4 days.

• Implant slowly releases hormone over ~3–4 months in cattle.

• In anti-doping testing: both testosterone and estradiol metabolites are readily detectable; synthetic estradiol can be detected for days–weeks, testosterone esters for weeks depending on dose.

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Sterogenic / Progestrogenic / Prolactin Effects

• Androgenic: yes (from testosterone component).

• Estrogenic: yes (from estradiol benzoate).

• Progestogenic: no progestin per se, but high estrogen can indirectly influence prolactin levels.

• Prolactin: can be elevated secondarily due to high estrogen.

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Anabolic : Androgenic Ratio

• The testosterone propionate part has the classic ≈100:100 (1:1) anabolic/androgenic ratio.

• The estradiol part is not anabolic or androgenic in the traditional sense; it’s estrogenic.

• So there is no true single “ratio” for the combined product because it’s a mixed hormone implant.

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In short: Synovex is a cattle implant combining testosterone propionate with estradiol benzoate to accelerate growth. It is not an anabolic steroid designed for humans, and its hormonal effects are mixed androgenic and estrogenic rather than purely anabolic.