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  1. #1
    Rickson's Avatar
    Rickson is offline AR-Hall of Famer
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    Jul 2002

    Esters Explained

    This is a nice relatively simplified explanation of how esters work. I am not sure where it originated but I got it off AF from Dragon.

    One of the most misunderstood subjects in the world of steroids is the ester--the mechanism by which injectable esterified
    steroids like testosterone cypionate , testosterone enanthate , and Sustanon work. If you take a quick look around the Internet
    you will probably find countless articles that consider one form of a steroid far more effective than another. Arguments over
    the superiority of cypionate to enanthate , or Sustanon to all other testosterones are of course very common. Such arguments
    are in all practicality, baseless. In this report we'll take an authoritative look at the ester and what specifi- cally it does to a

    1. WHAT AN ESTER IS, AND HOW IT WORKS I'm sure that if you have taken an interest in anabolic steroids you have
    noticed the similarities on the labeling of many drugs. Let's look at testosterone for example. One can find compounds like
    testosterone cypionate, enanthate, propionate , heptylate; caproate, phenylpropionate, isocaproate, decanoate, acetate, the list
    goes on and on. In all such cases the parent hormone is testosterone, which had been modified by adding an ester (enanthate,
    propionate etc.) to its structure. The following question arises: What is the difference between the various esterified versions
    of testosterone in regards to their use in bodybuilding? An ester is a chain composed primarily of carbon and hydrogen atoms.
    This chain is typically attached to the parent steroid hormone at the 17th carbon position (beta orientation), although some
    compounds do carry esters at position 3 (for the purposes of this article it is not crucial to understand the exact posi- tion of the
    ester). Esterification of an injectable anabolic/an- drogenic steroid basically accomplishes one thing, it slows the release of the
    parent steroid from the site of injection. This happens because the ester will notably lower the water solubility of the steroid,
    and increase its lipid (fat) solubility. This will cause the drug to form a deposit in the muscle tissue, from which it will slowly
    enter into circulation as it is picked up in small quantities by the blood. Generally, the longer the ester chain, the lower the
    water solubility of the compound, and the longer it will take to for the full dosage to reach general circulation. Slowing the
    release of the parent steroid is a great benefit in steroid medicine, as free testosterone (or other steroid hormones) previously
    would remain active in the body for a very short period of time (typically hours). This would necessitate an unpleasant daily
    injection schedule if one wished to maintain a continuous elevation of testoste- rone (the goal of testosterone replacement
    therapy). By adding an ester, the patient can visit the doctor as infrequently as once per month for his injection, instead of
    having to constantly re- administer the drug to achieve a therapeutic effect. Clearly without the use of an ester, therapy with
    an injectable anabolic/ androgen would be much more difficult. Esterification temporarily deactivates the steroid molecule.
    With a chain blocking the 17th beta position, binding to the androgen receptor is not possible (it can exert no activity in the
    body). In order for the compound to become active the ester must therefore first be removed. This automatically occurs once
    the compound has filtered into blood circulation, where esterase enzymes quickly cleave off (hydrolyze) the ester chain. This
    will restore the necessary hydroxyl (OH) group at the 17th beta position, enabling the drug to attach to the appropriate
    receptor. Now and only now will the steroid be able to have an effect on skeletal muscle tissue. You can start to see why
    considering tes- tosterone cypionate much more potent than enanthate makes little sense, as your muscles are seeing only free
    testosterone no matter what ester was used to deploy it.

    2. ACTIONS OF DIFFERENT ESTERS There are many different esters that are used with anabolic/ androgenic steroids,
    but again, they all do basically the same thing. Esters vary only in their ability to reduce a steroid's water solu- bility. An ester
    like propionate for example will slow the release of a steroid for a few days, while the duration will be weeks with a decanoate
    ester. Esters have no effect on the tendency for the parent steroid to convert to estrogen or DHT (dihydrotestosterone: a more
    potent metabolite) nor will it effect the overall muscle-building potency of the compound. Any differences in results and side
    effects that may be noted by bodybuilders who have used various esterified versions of the same base steroid are just issues
    of timing. Testosterone enanthate causes estrogen related problems more readily than Sustanon, simply because with
    enanthate testosterone levels will peak and trough much sooner (1-2 week release duration as opposed to 3 or 4). Likewise
    testosterone suspension is the worst in regards to gyno and water bloat because blood hormone levels peak so quickly with this
    drug. Instead of waiting weeks for testosterone levels to rise to their highest point, here we are at most looking at a couple of
    days. Given an equal blood level of testosterone, there would be no difference in the rate of aromatization or DHT conversion
    between different esters. There is simply no mechanism for this to be possible. There is however one way that we can say an
    ester does technically effect potency; it is calculated in the steroid weight. The heavier the ester chain, the greater is its
    percentage of the total weight. In the case of testosterone enanthate for example, 250mg of esterified steroid (testosterone
    enanthate) is equal to only 180mg of free testos- terone. 70mgs out of each 250mg injection is the weight of the ester. If we
    wanted to be really picky, we could consider enanthate slightly MORE potent than cypionate (I know this goes against popular
    thinking) as its ester chain contains one less carbon atom (therefore taking up a slightly smaller percentage of total weight).
    Propionate would of course come out on top of the three, releasing a measurable (but not significant) amount more
    testosterone per injection than cypionate or enanthate.

    ESTER PROFILES Sustanon: The "king" of testosterone blends. The four different testosterone esters in this product
    certainly look appealing to the consumer, there is no denying that. But for the athlete I think it is all just a matter of marketing
    (Hell, why buy one ester when you can get four?). In clinical situations I can see some strong uses for it. If you were
    undergoing testosterone replacement therapy for example, you would probably find Sustanon a much more comfortable option
    than testosterone enanthate. You would need to visit the doctor less frequently for an injection, and blood levels should be
    more steadily maintained between treatments. But for the bodybuilder who is injecting 4 ampules of Sustanon per week, there
    is no advantage over other testos- terone products. In fact, the high price tag for Sustanon usually makes it a very poor buy in
    the face of cheaper testosterone enanthate/ cypionate. Bodybuilders should probably stop looking at the four ester issue, and
    stick with totals (Sustanon is just a 250mg testosterone ampule). Were enanthate to be available for say $10 per amp of
    250mg, and Sustanon priced nearly double that, buying the Sustanon would be like throwing money away. If you could get
    nearly double the milligram amount for the same price with enanthate, this is the better product to go with hands down. Leave
    the high priced stuff for the guys who don't know any better.

    IN CONCLUSION While the advent of esters certainly constitutes an invaluable advance in the field of anabolic steroid
    medicine, clearly you can see that there is no magic involved here. Esters work in a well-understood and predictable manner,
    and do not alter the activity of the parent steroid in any way other than to delay its release. Although the lure surrounding
    various steroid products like testosterone cypionate, Sustanon, Omnadren etc. certainly makes for interesting conversation,
    realistically it just amounts to misinformation that the athlete would be better off ignoring. Testosterone is testosterone and
    anyone who is going to tell you one ester form of this (or any) hormone is much better than another one should do a little more
    research, and a lot less talking.

    Acetate: Chemical Structure C2H4O2. Also referred to as Acetic Acid; Ethylic acid; Vinegar acid; vinegar;
    Methanecarboxylic acid. Acetate esters delay the release of a steroid for only a couple of days. Contrary to what you may
    have read, acetate esters do not increase the tendency for fat removal. Again, there is no known mechanism for it to do so.
    This ester is used on oral primobolan tablets (metenolone acetate), Finaplix (trenbolone acetate) implant pellets, and
    occasionally testosterone.

    Propionate: Chemical Structure C3H6O2. Also referred to as Carboxyethane; hydroacrylic acid; Methylacetic acid;
    Ethylformic acid; Ethanecarboxylic acid; metacetonic acid; pseudoacetic acid; Propionic Acid. Propionate esters will slow the
    release of a steroid for several days. To keep blood levels from fluctuating greatly, propionate compounds are usually injected
    two to three times weekly. Testosterone propionate and methandriol dipropionate (two separate propionate esters attached to
    the parent steroid methandriol) are popular items.

    Phenylpropionate: Chemical Structure C9H10O2. Also referred to as Propionic Acid Phenyl Ester. Phenylpropionate will
    extend the release of active steroid a few days longer than propionate. To keep blood levels even, injections are given at least
    twice weekly. Durabolin is the drug most commonly seen with a phenylpropionate ester (nandrolone phenylpropionate),
    although it is also used with testoste- rone in Sustanon and Omnadren.

    Isocarpoate: Chemical Structure C6H12O2. Also referred to as Isocaproic Acid; isohexanoate; 4-methylvaleric acid.
    Isocaproate begins to near enanthate in terms of release. The duration is still shorter, with a notable hormone level being
    sustained for approximately one week. This ester is used with testosterone in the

    Also referred to as Hexanoic acid; hexanoate; n-Caproic Acid; n-Hexoic acid; butylacetic acid; pentiformic acid; pentylformic
    acid; n-hexylic acid; 1-pentanecarboxylic acid; hexoic acid; 1-hexanoic acid; Hexylic acid; Caproic acid. This ester is identical
    to isocarpoate in terms of atom count and weight, but is laid out slightly different (Isocaproate has a split configuration, difficult
    to explain here but easy to see on paper). Release duration would be very similar to isocaproate (levels sustained for
    approximately one weak), perhaps coming slightly closer to enanthate due to its straight chain. Caproate is the slowest
    releasing ester used in Omnadren, which is why most athletes notice more water retention with this compound.

    Enanthate: Chemical Structure C7H14O2. Also referred to as heptanoic acid; enanthic acid; enanthylic acid; heptylic acid;
    heptoic acid; Oenanthylic acid; Oenanthic acid. Enanthate is one of the most prominent esters used in steroid manufac- ture
    (most commonly seen with testosterone but is also used in other compounds like Primobolan Depot). Enanthate will release a
    steady (yet fluctuating as all esters are) level of hormone for approximately 10-14 days. Although in medicine enanthate
    compounds are often injected on a bi-weekly or monthly basis, athletes will inject at least weekly to help maintain a uniform
    blood level.

    Cypionate: Chemical Structure C8H14O2. Also referred to as Cyclopentylpropionic acid, cyclopentylpropionate. Cypionate is a
    very popular ester here in the U.S., although it is scarcely found outside this region. Its release duration is almost identical to
    enanthate (10-14 days), and the two are likewise thought to be interchangeable in U.S. medicine. Althletes commonly hold the
    belief than cypionate is more powerful than enanthate, although realistically there is little difference between the two. The
    enanthate ester is in fact slightly smaller than cypionate, and it therefore releases a small (perhaps a few milligrams) amount of
    steroid more in comparison.

    Decanoate: Chemical Structure C10H20O2. Also referred to as decanoic acid; capric acid; caprinic acid; decylic acid,
    Nonanecarboxylic acid. The Decanoate ester is most commonly used with the hormone nandrolone (as in Deca -Durabolin)
    and is found in virtually all corners of the world. Testosterone decanoate is also the longest acting constituent in Sustanon,
    greatly extending its release duration. The release time with Decanoate compounds is listed to be as long as one month,
    although most recently we are finding that levels seem to drop significantly after two weeks. To keep blood levels more
    uniform, athletes (as they have always known to do) will follow a weekly injection schedule.

    Undecylenate: Chemical Structure C11H20O2. Also referred to as Undecylenic acid; Hendecenoic acid; Undecenoic acid.
    This ester is very similar to decanoate, containing only one carbon atom more. Its release duration is likewise very similar
    (approximately 2-3 weeks), perhaps extending a day or so past that seen with decanoate. Undecylenate seems to be exclusive
    to the veterinary preparation Equipoise (boldenone undecylenate), although there is no reason it would not work well in
    human-use preparations (Equipoise certainly works fine for athletes). Again, weekly injections are most common.

    Undecanoate: Chemical Structure C11H22O2. Also referred to as Undecanoic Acid; 1-Decanecarboxylic acid; Hendecanoic
    acid; Undecylic acid. Undecanoate is not a commonly found ester,and only appears to be used in the nandrolone preparation
    Dynabolan , and oral testosterone undecanoate (Andriol ). Since this ester is chemically very similar to undecylenate (it is only 2
    hydrogen atoms larger), it has a similar release duration (approximately 2-3 weeks). Although this ester is used in the oral
    preparation Andriol, there is no reason to believe it carries any properties unique of other esters. Andriol in fact works very
    poorly at delivering testosterone, bolstering the idea that oral administration is not the idea use of esterified androgens.

    Laurate: Chemical structure C12H24O2. Also referred to as Dodecanoic acid, laurostearic acid, duodecyclic acid,
    1-undecanecarboxylic acid, and dodecoic acid. Laurate is the longest releasing ester used in commercial steroid production,
    although longer acting esters do exist. Its release duration would be closer to one month than the other esters listed above,
    although realistically we are probably to expect a notable drop in hormone level after the third week. Laurate is exclusively
    found in the veterinary nandrolone preparation Laurabolin , perhaps seen as slightly advantageous over a decanoate ester due
    to a less frequent injection schedule. Again athletes will most commonly inject this drug weekly, no doubt in part due to its low
    strength (25mg/ml or 50mg/ml).

  2. #2
    Rickson's Avatar
    Rickson is offline AR-Hall of Famer
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    More READS

    Esters of nandrolone injected intramuscularly, are absorbed from the depot according to the kinetics of a first-order reaction. The nature of the fatty acid chain in the ester determines the half-life of the compound in the depot. Once released from the depot, the ester is rapidly hydrolyzed by the esterases in the plasma. As a result, free nandrolone is the pharmacologically active agent whereas its availability to the target organs depends on the half-life time of the ester in the depot. It has been demonstrated that various androgenic target organs respond in a different manner to the changes in the concentration of nandrolone occurring during the period of resorption of the ester. This might explain the dissociation of anabolic from androgenic effects observed with esters of nandrolone.


    Following intramuscular injection of either 50 mg 19-nortestosterone-3-(p-hexoxyphenyl)-propionate (NP) or 50 mg 19-nortestosterone-decanoate (ND) serum 19-NorTestosterone increased rapidly to maximal concentrations of 4.6 +/- 3.2 and 2.0 +/- 1.3 nmol/l (+/-SD), respectively, in the 6 volunteers. The half-life time was 8 days for ND and 21 days for NP. Based on these findings a clinical trial with NP was performed. NP was given to 5 healthy men in doses of 100 mg/week for the first 3 weeks followed by 200 mg/week for 10 further weeks. Serum NT levels increased gradually and maximal concentrations were reached in the 13th treatment week (20.2 +/- 3.4 nmol/l). Measurable amounts of NT were detectable for 19 weeks after the last injection. The study shows that NT accumulates under this treatment regime and wider spacing of the injection intervals may be possible in future trials.


    The suggestion that the biological response to an oily intramuscular injection of testosterone ester is regulated by rapid accumulation of the steroid in body fat, followed by a slow release, has been tested by comparing the release rates of 14C-labelled testosterone propionate from different solvents following intramuscular injection into rats. Disappearance from the injection site was rectilinearly related to in-vitro partition coefficients, but elimination of radioactivity in urine and faeces was significantly longer, and the same for all four solvents. Testosterone and testosterone propionate were found in equal concentration in body fat, 2 and 3 days after injection, but their concentrations were too low to form an effective depot. It is suggested that the delay in release, and the independence of the delay on the nature of the solvent is a consequence of biliary recycling of testosterone.


    Nandrolone decanoate (Deca -Durabolin ) was injected intramuscularly into healthy volunteers. One group of females received one injection of 100 mg and three groups of males received one injection of 200 mg, two repeat injections of 100 mg or four repeat injections of 50 mg respectively. The serum levels of nandrolone (19-nortestosterone) were determined by radioimmunoassay and used to estimate pharmacokinetic parameters. The following pharmacokinetic parameters were found: a mean half-life of 6 days for the release of the ester from the muscular injection depot into the general circulation; a mean half-life of 4.3 h for the combined processes of hydrolysis of nandrolone decanoate and of distribution and elimination of nandrolone; a mean nandrolone serum clearance of 1.55 1 X h-1 X kg-1. The half-life of hydrolysis of nandrolone decanoate in serum was of the order of one hour or less. The data are consistent with linear kinetics.

  3. #3
    Spoon's Avatar
    Spoon is offline 'Lurker at the threshold'
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    Very educational read!

  4. #4
    animal-inside's Avatar
    animal-inside is offline Senior Member
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    somewhere in Canada
    needs to be bumped b/c sooo many newbie questions would get answered by reading it

  5. #5
    Mr. Sparkle's Avatar
    Mr. Sparkle is offline Slinabolic Vet / Retired
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    Lovin Alba's butt

  6. #6
    Da Bull's Avatar
    Da Bull is offline Banned
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    Great info Rickson!!!!

  7. #7
    chicamahomico's Avatar
    chicamahomico is offline Respected Member
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    Hoss's Moms bedroom

  8. #8
    bornbad71's Avatar
    bornbad71 is offline Anabolic Member
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    Very good read Rickson.........more ppl need to read this.

  9. #9
    UrbanLegend's Avatar
    UrbanLegend is offline Senior Member
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    Lets keep this bumped, everyone should get a chance to read it.

  10. #10
    nsa is offline King of Supplements
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    I think it should be a sticky...

  11. #11
    Froggy's Avatar
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    Very interesting! Great post!

  12. #12
    nate da gr8 is offline Associate Member
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    Great post bro

  13. #13
    BajanBastard is offline VET Retired
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    Half-life time for the Nandrolone phenylprop 21 days, Nandrolone decanoate 8 days...........not vica versa?

  14. #14
    sp9's Avatar
    sp9 is offline MMA Competition Sentinel
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    Land of milk and honey.
    Should move to the Educational threads. Good Info. There is already another thread by basskiller with the same title in the educational section, different info I am sure.

  15. #15
    cpt steele's Avatar
    cpt steele is offline Anabolic Member
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    Bump this for newbies

  16. #16
    beeffreak6's Avatar
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    great post bro! hell ya!

  17. #17
    JDog3497's Avatar
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    Excellent Post Bro!

  18. #18
    usualsuspect's Avatar
    usualsuspect is offline Anabolic Member
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    Informative as always.

  19. #19
    map200uk's Avatar
    map200uk is offline Anabolic Member
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    great post, thanks

  20. #20
    Join Date
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    Cajun Country
    Great for newbies. Bump Bump bump it up.

  21. #21
    monstercojones's Avatar
    monstercojones is offline The Anabolic Assassin
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    fake out... i thought this was going to be a post on how to avoid girls named 'esther'.

    o well... it's still a great post rickson... valuable information for everyone.

    i'll give this a solid BUMP for anyone who hasnt read it yet.

  22. #22
    Blown_SC is offline Retired Vet
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    Quote Originally Posted by scottp999
    Should move to the Educational threads. Good Info. There is already another thread by basskiller with the same title in the educational section, different info I am sure.
    The first post by Rickson is the same as what BassKiller has written...
    But, Rickson's second post is additional information...
    Thanks for the good read bro...

  23. #23
    takincareofbusiness's Avatar
    takincareofbusiness is offline Associate Member
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    Great read!

  24. #24
    MR_T's Avatar
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    yo momas house
    thanks for the post bro.. very helpful

  25. #25
    skinnyguy79 is offline New Member
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    Ive been looking for a post like this. Great work Rickson! Thanx

  26. #26
    panntastic's Avatar
    panntastic is offline "cool as shit and knows his stuff"
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    Quote Originally Posted by skinnyguy79
    Ive been looking for a post like this. Great work Rickson! Thanx
    9 year old bump good work

  27. #27
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    In the pub
    great piece of text!!

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