Synovex — testosterone propionate & estradiol

Synovex is a blended-ingredient steroid implant preparation, which is available only as a veterinary item for use in cattle.The implant comes in the form of small pellets, which are pushed into the ear of an animal with a very large implant gun. Once implanted, the pellets slowly dissolve, providing an extended release of steroids for many weeks. The hormone content of Synovex is mixed, with each pellet containing 25 mg testosterone propionate and 2.5 mg estradiol benzoate. This 10:1 ratio has been demonstrated to provide an added anabolic/weight gaining effect in feed animals, improving the value of the livestock. Given its estrogen content, Synovex is clearly not an ideal steroid for humans. Most athletes have only become attracted to this product out of sheer desperation for legitimate anabolics, as cattle implants like this are not regulated as controlled substances in the U.S. to spite their steroid content. Otherwise, a pure testosterone propionate product would be much more appropriate.

Brand name Synovex, Testosterone propionate & estradiol
Androgenic 100
Anabolic 100
Standard standard
Chemical Names 4-androsten-3-one-17-beta-ol
Estrogenic Activity moderate
Progestational Activity low

Synovex History

Testosterone propionate plus estrogen implant pellets were first approved by the U.S. Food and Drug administration for use in heifers in 1958. Diethylstilbestrol, a potent estrogen often used to increase animal carcass weight, had been approved four years earlier for use in cattle, however, and would remain the leading product for many years. Syntex introduced their version of testosterone/estrogen pellets (Synovex) during the early 1970’s, as part of the company’s new Animal Health division. This was during a time a time when diethylstilbestrol was getting a great deal of negative publicity. Synovex became a huge seller when the FDA banned the use of diethylstilbestrol in 1973, the product quickly capturing more than 50% of the market for growth-promoting implants. The popularity of Synovex soon caught the attention of other companies, a number of which soon started making their own blended testosterone/estrogen implants. Popular brand names in the U.S. have included F-TO (Upjohn), Heifer-oid (Boehringer), and Implus (Upjohn). Synovex and other testosterone/estrogen pellets remain widely available in the U.S. and abroad today, although are not highly popular with athletes given their estrogen content.

How is Synovex Supplied

Synovex contains 25 mg of testosterone propionate and 2.5 mg of estradiol benzoate in a small sterile implantation pellet. The number of pellets in each cartridge dose will vary depending on the intended target animal. Implants denoted “H” for heifer will carry the most; in the case of U.S. Synovex-H it is 80 pellets (10 doses consisting each of 8 pellets). We will see a slightly lower pellet count in the “S” implants (steer) and “C” (calf ) cartridges.

Structural Characteristics of Synovex

Testosterone propionate is a modified form of testosterone, where a carboxylic acid ester (propionic acid) has been attached to the 17-beta hydroxyl group to slow the release of testosterone from the area of implantation. This preparation also contains an ester (benzoic acid) of estradiol.

Synovex Side Effects (Estrogenic)

Testosterone is readily aromatized in the body to estradiol (estrogen). Additionally, this preparation contains an active estrogen. Elevated estrogen levels can cause side effects such as increased water retention, body fat gain, and gynecomastia. This steroid preparation is considered to be highly estrogenic. An anti-estrogen such as clomiphene citrate or tamoxifen citrate may be necessary to prevent estrogenic side effects. One may alternately use an aromatase inhibitor like Arimidex (anastrozole), although it will not have an affect on the additional estrogen present in the preparation. Since water retention and loss of muscle definition are common with highly estrogenic steroid products, this drug is usually considered a poor choice for dieting or cutting phases of training. It would only be appropriate during bulking phases, where the added water retention will support raw strength and muscle size, and help foster a stronger anabolic environment.

Synovex Side Effects (Androgenic)

Testosterone is the primary male androgen, responsible for maintaining secondary male sexual characteristics. Elevated levels of testosterone are likely to produce androgenic side effects including oily skin, acne, and body/facial hair growth. Men with a genetic predisposition for hair loss (androgenetic alopecia) may notice accelerated male pattern balding. Those concerned about hair loss may find a more comfortable option in nandrolone decanoate, which is a comparably less androgenic steroid. Women are warned of the potential virilizing effects of anabolic/androgenic steroids, especially with a strong androgen such as testosterone. These may include deepening of the voice, menstrual irregularities, changes in skin texture, facial hair growth, and clitoral enlargement.

Synovex Side Effects (Hepatotoxicity)

Testosterone and estrogen do not have hepatotoxic effects; liver toxicity is unlikely.

Synovex Side Effects (Cardiovascular)

Anabolic/androgenic steroids can have deleterious effects on serum cholesterol. This includes a tendency to reduce HDL (good) cholesterol values and increase LDL (bad) cholesterol values, which may shift the HDL to LDL balance in a direction that favors greater risk of arteriosclerosis. The relative impact of an anabolic/androgenic steroid on serum lipids is dependant on the dose, route of administration (oral vs. injectable), type of steroid (aromatizable or non-aromatizable), and level of resistance to hepatic metabolism. Testosterone tends to have a much less dramatic impact on cardiovascular risk factors than synthetic steroids. This is due in part to its openness to metabolism by the liver, which allows it to have less effect on the hepatic management of cholesterol. The aromatization of testosterone to estradiol also helps to mitigate the negative effects of androgens on serum lipids. The added estrogen in this product may further help to offset some of the androgenic effect on lipid values, and the preparation may, therefore, have a weaker impact on cholesterol than a comparably dosed straight testosterone product. Anabolic/androgenic steroids may also adversely affect blood pressure and triglycerides, reduce endothelial relaxation, and support left ventricular hypertrophy, all potentially increasing the risk of cardiovascular disease and myocardial infarction.

Synovex Side Effects (Testosterone Suppression)

All anabolic/androgenic steroids when taken in doses sufficient to promote muscle gain are expected to suppress endogenous testosterone production. Testosterone is the primary male androgen, and offers strong negative feedback on endogenous testosterone production. The added estrogen will also provide negative-feedback suppression. This preparation should have a strong effect on the hypothalamic regulation of natural steroid hormones. Without the intervention of testosterone stimulating substances, testosterone levels should return to normal within 1-4 months of drug secession. Note that prolonged hypogonadotrophic hypogonadism can develop secondary to steroid abuse, necessitating medical intervention.

To help reduce cardiovascular strain it is advised to maintain an active cardiovascular exercise program and minimize the intake of saturated fats, cholesterol, and simple carbohydrates at all times during active AAS administration. Supplementing with fish oils (4 grams per day) and a natural cholesterol/antioxidant formula such as Lipid Stabil or a product with comparable ingredients is also recommended.

Synovex Administration (General)

Synovex implant pellets were not designed for human consumption. To make use of these pellets, they must be converted into another (more suitable) delivery form. To do this, an athlete will typically grind them up and rub them on the skin in a 50/50 mixture of DMSO and water to facilitate transdermal delivery. Alternately, one may mix up a homebrew injection with the pellets. This is done by grinding them into a fine powder and introducing the powder into filtered oil or an oil-based steroid. One should remember that the practice of preparing Synovex for injection is not going to be sterile, and as such could be potentially dangerous. Note that some methods have additionally been published for removing the estrogen from the pellets, to make the drug more comfortable to use. They generally involve the use of highly flammable materials, take a number of different steps to complete, and leave some estrogen when the process is over, however, usually making the process more trouble than it is worth.

Synovex Administration (Men)

Synovex is not approved for use in humans. Prescribing guidelines are unavailable. When used for physique- or performance-enhancing purposes (very rarely), the dose is calculated based on the route of administration. When given by transdermal delivery, a bioavailability rate of no more than 10% is assumed. A daily dosage of 4 pellets (100 mg) would, therefore, provide the equivalent of 70 mg per week of testosterone propionate (as given by injection). When given by injection a dose of 100 mg every second or third day is most common. The drug is generally taken for no more than 8 weeks, and is used almost exclusively during bulking phases of training. Those who have experimented with this product have been generally disappointed with the results, as the added estrogen has often resulted in rapid gynecomastia, noticeable body fat accumulation, and severe water retention. In many cases the water retained has caused an unsightly bloated look (extreme loss of definition).

Synovex Administration (Women)

Synovex is not approved for use in humans. Prescribing guidelines are unavailable. Synovex is not recommended for women for physique- or performance-enhancing purposes due to its strong androgenic nature and tendency to produce virilizing side effects.

Synovex Availability

Synovex is rarely found on the black market, given that the product is in poor demand and generally can be obtained through legitimate Agricultural or Veterinary supply stores. No counterfeits have ever been known to exist.

Newbies Research Guide reference

Description: Implus (Synovex) is another of the cattle implants that bodybuilders are utilizing in the attempt to get steroids. This product comes in a rotary cartridge that contains 20 pellets per cartridge with 5 cartridges in a box. Each pellet is 3” in length and contains 200 mgs. of testosterone propionate as well as 20 mgs. of estradiol benzoate. The estradiol is added to the product to increase size in cattle. Implus is a drug intended for veterinarian use in cattle to increase weight gain and feed efficiency. This product is identical to Synovex-H except that there are twice the amount of pellets in one cartridge and the black market price is marketly less expensive on this product. This is probable due to the fact that most people are only aware of Finaplix and Synovex as a rule. The unfortunate side to using this for athletic gains is that it contains estradiol which will cause big time gyno if it is left in the product and used as is. You can read further about the effects of testosterone propionate on it’s page. I don’t want to be redundant here. As far as side effects go, if you don’t seperate the estradiol from the pellets you are going to be screwed with gyno, you don’t want to have. These are not the most sanitary things either. Keep in mind that these were made for animals and there is not near the precautions taken when making these as there is with medicine. The other side effects are the same as with testosterone propionate.

There is a way to remove the estradiol from the implant by doing to following:
Gather about 2-3 of the pellets together and grind them up with the back of a spoon and make the pellets into as fine of a powder as you can. Then, get 50 ml of diethyl ether (pretty easy to obtain from any chemical supplier) and mix this combination together in a bowl. You then have to let the solution evaporate allowing crystals to form in the bowl. The crystals that form at the top of the bowl contain the estradiol that you are trying to get rid of. You then need to place this solution in the freezer overnight to help aid in most of the estradiol being removed from the testosterone-ether solution. By the next morning, you will pull this solution out of the freezer and the frozen crystallized estradiol will have risen to the top of the bowl (just like bread rising in the oven, he! he!). You then would scrape or scoop the crystals off the top of the solution and get rid of them. The remaining crystal that are left at the bottom of the bowl contain the testosterone propionate that you are trying to get. Then let them air dry for a while to get the majority of the ether off the crystals. You then need to place these crystals in the oven on a low temperature to get rid of any ether that remains for a few hours and you should have left the dry testosterone propionate crystals that you need with a minimum of ether left in them. Make sure you have let them air dry first though. You don’t want to blow up the house by putting a bowl of
ether in the oven just because you are a little to fucking impatient to get big. Make sure that it is a electric oven as well, you definitely don’t want to use a gas oven for this procedure.

After separating the testosterone propionate from the solution, you have two choices for using this compound. One way is to use DMSO (dimethyl sulfoxide) to make the steroid transdermal meaning that it will now pass through the skin. There are a variety of forms that DMSO is available but the gel version works the best and is the easiest to use. What you want to do is grind up the crystals to as fine of a powder as you can and then mix it with one teaspoonful of DMSO and one of water and apply to the skin every 2-3 days as that is the effective time span for testosterone propionate. You can then rub this compound into your skin and wrap the area with a piece of saran wrap to help get the compound to absorb into the skin easier, since it will heat it between the saran wrap and your body to aid in absorption.

The other way to take this compound is through injection. You can do this by mixing the compound with about 2 cc of oil or sterile water and injecting it that way. Even grinding up the particles as fine as you can you will have to use about an 18 gauge needle to inject this concoction. I would suggest using the DMSO method above to do this.
Effective Dose: 50 - 100 mgs. every other day.
Street Price: The going street price on this product is about $70 per cartridge which will yield about 4000 mgs. of testosterone propionate.
Stacking Info: This compound is commonly stacked with Winstrol Depot, Metandiabol or Reforvit-B, or Parabolan


Wlliam Llewellyn (2011) - Anabolics
Newbies Research Guide

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