Apart from changing the affinity for a lot a structures, making a steroid with completely different characteristics, the main problem here was that it invoked a level of hepatoxicity. Often minor, sometimes severe ( anadrol, Halotestin). This meant that treatment could not be continued for extended periods of time in complete safety. The demand for an oral steroid that can be used for lengthy treatment has been high since the very beginning. First of all its never easy for a doctor to sell his patients on injection protocols (many fear or at least dislike needles) and for the doctor too it would be easier if the patient could take a pill than to have him come back every other week for an injection. So the pressure was on to create a steroid that wouldn't require a 17-alpha-methyl alteration.
The answer was to seek a new way of delivery, that bypassed the liver, so that no alteration was needed to protect the steroid from being deactivated in the liver. That way was found in lymphatic absorption. As with many paths of uptake, this one too is very specific and limited. The lymphatic system is a series of heavily filtered channels intended for the resorption of water. When blood is delivered to a tissue through the arterial system, it is depleted of oxygen and nutrients, and then lead back to the heart by the venous system. Unfortunately only about 85% of the fluid is readily re-absorbed. That means 15% stays behind in the tissue and if that process where to continue day and night, we'd all swell up like Marshmallow man and explode in less than a week. That's why, inside tissues, there is another extended capillary system other than the cardiovascular one. The lymphatic system. This has the sole purpose of draining water from tissue. This is why it mostly only transports water. Its also heavily filtered by lymph nodes throughout the body that will remove almost everything, because the system is easily accessible and if not properly filtered a virus or cancer cell could easily spread throughout the body in this manner. But in the digestive tract it seems the lymph system makes an exception. Lymph fluid is usually clear (since its pure water), but in this area its troubled. That's because it appears to absorb oils and fats as well.
Steroids are made from the prime storage of fat in the body, cholesterol. So there is a definite possibility here. And the lymphatic system, for 75-80%, empties itself in the major duct (ductus thoracicus), which in turn empties itself in the angulus venosus, where the vena jugularis interna (internal jugular vein) and the vena subclavia (vein below the collarbone) meet, right before they enter the heart through a common vein. That means, without having to pass the liver, these fats can be delivered straight to the heart. Now the question is, if indeed it was readily absorbed by the lymphatic system, why alter a steroid at all to survive the liver ? Obviously it doesn't get through to any great extent. That's because it absorbs only actual fats. This carrier therefore targets the solution of the steroid in an oil, so that it will be absorbed with the oil. It also seeks to make the compound more lipophillic so solution is more complete and permanent. As we also learned from injectable steroids, the way to make a compound more lipophillic is by attaching an ester. The longer the ester is, the more lipophillic it makes the steroid. In this case they opted for an undecanoate ester, which has a length of 11 carbons, the longest ester used to date.
In this case we are talking about a testosterone undecanoate. It is dissolved in a type of sterile oil and then sealed inside a cap. As a whole, the dissolved steroid is then easily absorbed by the lymphatic system, prior to passing the liver, and delivered with ease to the heart where it is then sent out across the body. The system itself is ingenious and in theory perfect. Maximal delivery and no hepatoxicity. A potent steroid capable of being used for long treatments. However (I'm sure you saw that one coming) in practice things don't always turn out the way they appear in theory. In studies1 done on both men and women, andriol was shown to be a mild and inconsistent steroid at best. Mild is a problem that is easily solved with higher doses, but inconsistent is another story entirely. It seems that the amount that was delivered and the peak levels of testosterone in the blood as well as the length of activity, differed not only from person to person, but from day to day. That means a different person, from day to day, will get very varying levels of testosterone in the blood. And the differences were not minor.
One subject may have a peak level of 5 ng/mmol while another can have in excess of 50 ng/mmol. What's worse, the same person may get these levels on different days. In terms of its anabolic (ie non-medical) use, that means doses of 8-16 caps per day are being used. That's more than most will inject per week of the shorter cypionate and enanthate esters. Normally 1 cap delivers 40 mg of testosterone undecanoate. An ester releases the steroid in the blood, leaving us with approximately 25 mg of testosterone per cap (it's a long and heavy ester). That's 200-400 mg per day being used, and andriol being as novel as it is, isn't cheap or easy to come by. That makes it, at best, just as uninteresting as methyl-testosterone.
As far as the properties of this steroid go, like a propionate ester or a suspension injection, levels of testosterone, DHT and estrogen are easy to control, which makes this steroid a possibility for use during any time of the year, whether the athlete be cutting or bulking. The water retention is less notable than with longer esters, and if too high is easily controlled with Proviron or Nolvadex. Its pure testosterone, so if delivered in high enough doses, for reasons previously stated, it is of course a good mass builder with all the characteristics of testosterone. No more no less. It is of course a safe (to the liver), controllable oral steroid that can be used for extended periods of time, which does spark the interest of some, but anybody serious about gains will usually find andriol a very poor buy. Great invention for the medical world, but of little to no interest to the serious athlete.
Andriol doesn't have that many uses. When utilized in doses of 8-16 caps per day are used and it can obviously be stacked with most any other steroid. Water retention problems that are common with testosterone are usually controllable enough to warrant use even during cutting phases, and even if not Proviron can be added to maximize its potential. The use of ancillaries is generally not required as its very mild to begin with and most problems can be solved by discontinuing use or lowering the dose. The usual anti-estrogens can be used, but generally with the cost of andriol for what little it does makes it less appealing to invest in the likes of Nolvadex or arimidex. Caps are best spread out throughout the day. Most oral steroids have a 17-alpha-methyl alteration that changes affinity and binding of the steroid, so that a single dose is usually enough. With andriol delivery is swift, peak doses high, but the steroid never outlasts its half-life of 3-5 hours. So it should be taken in three equal doses throughout the day, preferably with meals as lymphatic absorption is promoted in the presence of bile and other secretions in the GI tract.