Steroid profile: Synovex


Chemical Composition

  • Testosterone base + Propionate ester
  • Molecular Weight (base): 288.429
  • Molecular Weight (ester): 74.0792
  • Formula (base): C19 H28 O2
  • Formula (ester): C3H6O2
  • Melting Point (base): 155
  • Melting Point (ester): 21C
  • Manufacturer: Multiple
  • Effective Dose (Men): 300-2000 mg+/week
  • Half-Life: 2-3 Days
  • Detection Time: 2-3 Weeks
  • Anabolic/Androgenic Ratio: 100/100

Synovex is testosterone with the addition of propionate ester, a short, fast-acting ester. Synovex is commonly referred to as Test Prop or just Prop. Furthermore, Synovex is a particularly popular kind of testosterone because of its fast-acting effects, relatively low water retention (especially compared to longer esters), and frequently few side effects. 



Synovex, a medication, comes in the shape of a tiny sterile implantation pellet that contains 25 mg of Test Prop and 2.5 mg of estradiol benzoate. The quantity of pellets in each cartridge dosage varies based on the desired target animal. For example, Synovex-H, which stands for heifer, comprises 80 pellets (10 dosages of 8 pellets each). 

Synovex is available in the form of a veterinary implant pellet that was not intended for human use; nevertheless, these pellets may be physically changed into a form acceptable for human use. Several labs and many people create a homebrew of Synovex employing a pretty difficult preparation and sterilisation procedure to obtain a well-formed oil solution for intramuscular injection. However, the safest and fastest approach to prepare Synovex is to ground it with Dimethyl sulfoxide (DMSO) in a 50/50 ratio for transdermal application.

Indications/Purpose & Side Effects

Effects of Synovex

For individuals with low testosterone levels, supplementing with Synovex can alleviate symptoms and restore normal testosterone levels. This means you won't experience the negative effects of low testosterone anymore. For athletes aiming to enhance performance, Synovex, being a versatile anabolic steroid, offers a wide range of benefits.

During the off-season, when athletes focus on gaining muscle mass and strength, Synovex becomes crucial. With adequate calorie intake, Synovex can promote significant increases in lean muscle mass and strength, thus aiding in efficient off-season growth while minimizing fat gain.

In the cutting phase, Synovex is valuable for preserving lean muscle mass while losing body fat. It helps maintain a strong metabolic rate, ensuring efficient fat-burning without sacrificing muscle tissue.
Regardless of the purpose of use, Synovex enhances muscular endurance and speeds up recovery, leading to overall improved athletic performance.

Side Effects of Synovex

Synovex is generally well-tolerated by healthy adult men, except those with low testosterone levels. While it has a high threshold of toleration, there are potential side effects associated with its use. For individuals with low testosterone levels, side effects are rare because Synovex simply replaces what the body lacks. However, for performance athletes who use higher-than-normal doses of the hormone, side effects may be more common. Nonetheless, most men can handle elevated testosterone levels well, although there is a limit that varies among individuals. To help understand these potential side effects, below is the categorized version and provided all the necessary information.

1- Estrogenic

The side effects of Synovex primarily revolve around its estrogenic properties. Testosterone can convert to estrogen through the aromatase enzyme, leading to potential issues such as gynecomastia (enlargement of breast tissue in males) and excess water retention. Excessive water retention can contribute to high blood pressure. Fortunately, managing and avoiding these estrogenic side effects of Synovex is relatively straightforward.

Men are often advised to use anti-estrogens when using exogenous testosterone. Two options are available: Selective Estrogen Receptor Modulators (SERMs) like Nolvadex (Tamoxifen Citrate) and Aromatase Inhibitors (AIs) like Arimidex (Anastrozole). AIs are more effective as they inhibit aromatization and decrease serum estrogen levels. SERMs, on the other hand, don't lower estrogen levels but bind to estrogen receptors, preventing estrogen from binding.

While AIs are more potent, they can adversely affect cholesterol levels, especially when combined with an aromatizing steroid like Synovex. SERMs don't negatively impact cholesterol and can even promote healthy cholesterol levels by acting as estrogen in the liver.

2- Androgenic

Synovex is a potent androgenic hormone and as a result, androgenic side effects are possible. The possible androgenic side effects of Synovex include acne, increased hair loss in those predisposed to male pattern baldness and body hair growth. While these side effects of Synovex are possible, they are highly dependent on genetic predispositions. Many men will not have an issue at all, while others may need to exercise a little caution.

The testosterone hormone can be reduced to dihydrotestosterone (DHT) due to it being metabolized by the 5-alpha reductase enzyme. This is what promotes the androgenic activity in the target areas of the skin and scalp. Some men may find a 5-alpha reductase inhibitor like Finasteride to be useful as it will reduce the hormone's relative androgenicity. It will not completely reduce this activity but it will have a pronounced effect.

3- Cardiovascular

Synovex can harm cholesterol, particularly HDL (good cholesterol), by lowering overall HDL levels. A therapeutic dosage should not result in a significant statistical decline, but when combined with an AI, it may enhance HDL suppression. With a supraphysiological dosage, overall HDL suppression of up to 20% is entirely achievable. If combined with an AI, it will most likely become frustrating.

If you’re going to supplement with Synovex, especially if you’re going to include an AI a cholesterol-friendly lifestyle will be important. The individual's diet should be rich in omega fatty acids, low in saturated fats and simple sugars, and plenty of cardiovascular activity should be part of your normal routine. Those who ensure a cholesterol-friendly lifestyle will rarely have an issue unless some underlying condition exists.

4- Testosterone

The side effects of Synovex will always include the suppression of natural testosterone production. For the low-level patient, this is of no concern of suppression of natural testosterone production because such an individual is not producing enough testosterone to begin with. For the performance athlete, during use, this is also no concern as the exogenous testosterone will provide your body with all it needs.

Once use is discontinued, natural testosterone production will begin again. This, however, does not apply to the low testosterone patient. A low-level patient will more than likely always need exogenous testosterone therapy.

For the performance athlete, although production will begin again on its own more are encouraged to implement a Post Cycle Therapy (PCT) plan. This will cut down the total recovery time and ensure you have enough testosterone for proper bodily function while your levels continue to naturally rise. No, a PCT plan will not return you to normal on its own, no PCT plan can do this, but it will ensure a more efficient and comfortable recovery. It will also greatly protect your lean muscle tissue. Once a cycle is discontinued and natural testosterone levels are low, it is very easy for cortisol to become the dominant hormone, and this will put your lean tissue at risk. Implement a PCT plan and this problem is solved.

An important note on natural testosterone recovery; this assumes severe damage was not done to the Hypothalamic-Pituitary-Testicular-Axis (HPTA) due to improper steroidal supplementation. It also assumes no prior low testosterone condition existed.

5- Hepatotoxicity

Synovex is not hepatotoxic. This anabolic steroid will present no stress or damage to the liver.


As a wonderful testosterone base, Synovex can be stacked with bulking cycle ingredients like

  • Equipoise
  • Halotestin
  • Deca-Durabolin (and other nandrolones)
  • Trenbolone
  • Dianabol

Furthermore, Synovex does of great job supporting definition and pre-contest cycles which often include

  • Winstrol
  • Primobolan
  • Oral Turinabol
  • Anavar
  • Clenbuterol, and Cytomel (T3)


  1. Herschler RC, Olmsted AW, Edwards AJ, et al. Production responses to various doses and ratios of estradiol benzoate and trenbolone acetate implants in steers and heifers. J Anim Sci. 1995;73(10):2873-2881.
  2. McLaughlin, C.L., Bechtol, D.T., Lawrence, T.E., Lechtenberg, K., Moseley, W.M., Prouty, F.L., Vanimisetti, B.H. and Waite, A.R., 2013. Comparison of the effects of long-acting Synovex One with Revalor-XS and Synovex Plus on growth performance and carcass quality in steers. The Professional Animal Scientist, 29(2), pp.147-156.
  3. Cleale RM, Amodie D, Bechtol DT, et al. Effects of estradiol benzoate and trenbolone acetate, alone or in combination at dose levels present in Synovex Choice, on performance by feedlot heifers. J Anim Sci. 2013;91(2):970-977.
  4. U.S. Food and Drug Administration. Finding of No Significant Impact in support of a supplemental NADA 141-043. June 29, 2014.
  5. Kahl, S., Bitman, J. and Rumsey, T.S., 1978. Effect of Synovex-S on growth rate and plasma thyroid hormone concentrations in beef cattle. Journal of animal science, 46(1), pp.232-237.