Anabolic steroids have traditionally been taken in cycles, which are episodes of use lasting 6 to 12 weeks or more. However, there are athletes, such as some power lifters, who use the drugs on a relatively continuous basis and increase their doses at certain times of the year-for example, to prepare for a competition.
      Often, athletes will take more than one steroid at a time; this is referred to as "stacking." The supposed basis for stacking is that it allows the user to activate more receptor sites than if only one steroid is used, or that the user can achieve a synergistic effect with certain combinations of steroids. In addition, the athlete may use a number of other drugs concurrently or after a cycle (PCT) to further enhance physical capacities or to counteract the common side effects of steroids. These drugs include stimulants, diuretics, anti-estrogens, human chorionic gonadotropin (HCG), human growth hormone (hGH), anti-acne medications, as well as anti-inflammatories. They also tend to use natural food supplements, such as creatine, DHEA, multivitamins, protein and amino acids.
      The dose of anabolic steroids depends on the sport as well as the particular needs of the athlete. Endurance athletes use steroids primarily for their catabolism-blocking effects and employ doses at or slightly below physiologic replacement levels. Although sprinters desire similar results, the strength and power requirements of their activity result in doses that are approximately one and a half to more than double the replacement levels. Participants in the traditional strength sports seeking to "bulk up," have generally used amounts that exceed physiologic levels by 10 to 100 times, or more. Dosing patterns will also vary among athletes within a particular sport based on each athlete's training goals and response to the drugs and the biological activity of different anabolic steroids. Women, regardless of sport, are thought to generally use much lower doses of anabolic steroids than males.
      A steroid cycle should always be followed by a post-cycle treatment (PCT) that consist of a combination of drugs that interact with certain body responses to reverse the negative feedback loop of the hypothalamic-pituitary-gonadal axis (HPGA/HPTA). The construction of a proper PCT cycle will be discussed later.
      For this chapter we will focus on the design of a steroid stack.
      Due to the differences in physical characteristics of individuals like weight, height and age it is impossible to have a “one size fit all” kind of cycle that will meet everyone’s needs. Every athlete will require a custom cycle designed around their individual goals and body features.
      The first step in constructing your custom cycle will be to decide what you like to achieve. You might want to bulk up so that you fall into a new weight division. You might want to gain more strength or lean mass to help secure your rugby career. Maybe you want to cut down on your bodyfat percentage so that you have more muscular definition for your upcoming bodybuilding competition. Your goal can thus be to bulk, gain lean mass or to cut. Unfortunately it is not possible to bulk and cut at the same time, so decide on what you want to achieve first.
      Next you have to select the steroid(s) you plan to use. If this will be your first cycle it is recommended that you keep your stack as simple as possible. The proffered starting place of any cycle will be with testosterone as a base. Testosterone is found naturally in your body so the possibility for side-effects are greatly reduced compared to something like oxymetholone (Anapolon) for example.
      You are probably wondering which testosterone to choose, because there is a testosterone propionate, testosterone enanthate, testosterone cypionate and even a blend of different testosterones. All of these are essentially the same compound; the only difference is the ester or carboxylic acids attached to the testosterone molecule. The consequence of this is that the ester will determine the active life span (Half-Life) of the parent hormone. Such alterations will reduce the steroid's level of water solubility, and increase its oil solubility. Once an esterified compound has been injected, it will form a deposit in the muscle tissue (depot) from which it will slowly enter circulation. Generally the larger the ester chain, the more oil soluble the steroid compound will be, and the longer it will take for the full dosage to be released. Once free in circulation, enzymes will quickly remove the ester chain and the parent hormone will be free to exert its activity (while the ester is present the steroid is inert).
      To compare, an ester like decanoate can extend the release of active parent drug into the blood stream for three to four weeks, while it may only be extended for a few days with an acetate or propionate ester. The use of an ester allows for a much less frequent injection schedule than if using a water-based (straight) testosterone, which is much more comfortable for the patient.
      Longer esters do have some disadvantages and we must remember when calculating dosages, that the ester is figured into the steroid's measured weight. 100 mg of testosterone enanthate, therefore, contains much less base hormone than 100 mg of a straight testosterone suspension (in this case it equals 72mg of testosterone).
      It is also important to stress the fact that esters do not alter the activity of the parent steroid in any way. They work only to slow its release. It is quite common to hear people speak about the properties of different esters, almost as if they can magically alter a steroid's effectiveness. This is really nonsense. Enanthate is not more powerful than cypionate (perhaps a few extra milligrams of testosterone released per injection, but nothing to note), nor is Sustanon some type of incredible testosterone blend.
      The same goes for all other steroid molecules with attached esters. Basically a beginner would want to choose a steroid that requires less frequent injections, so something like testosterone enanthate or cypionate will be perfect as injections are only required weekly. More advanced users might want a steroid with less weight taken by the ester and something that works faster, so they will go for propionate or acetate compound. These will require much more frequent injections and it’s not uncommon to take them daily. Power lifters often use straight testosterone suspension before it’s their time to perform as it will work in less than 10 minutes after injecting. However it will leave your body just as quickly and to achieve stable blood concentrations will require injections every couple of hours making it impractical for bodybuilding use.
      When stacking different esterified steroids together it is advisable to choose esters of roughly the same ester chain length as that will allow you to inject them at the same intervals. For example- testosterone propionate and trenbolone acetate makes a very good stack because then you can mix both in one syringe before injecting every day or every second day. Another example is testosterone enanthate with trenbolone enanthate as that will allow weekly injections of both. However stacking testosterone propionate with trenbolone enanthate will only complicate your cycle unnecessarily, because that will require daily injections of the propionate and weekly injections of the enanthate compound. The more frequently you inject the more stable blood concentrations will be and thus providing better results in the long run.
      Below you will find a table containing the properties of the more common esters used on steroids:

      So far we have only been talking about injectable steroids and nothing about oral steroids. Chemists realized that by replacing the hydrogen atom at the steroid's 17th alpha position with a carbon atom (a process referred to as alkylation), its structure would be notably more resistant to breakdown by the liver thus making it possible to ingest steroids orally. A steroid with this alteration is commonly described as a C-17 alpha alkylated. There are many steroids modified this way but the most common are Dianabol, Anapolon, Winstrol, Anavar, Halotestin and Turinabol. The principle drawback to these 17 alpha alkylated compounds are that they place a notable amount of stress on the liver, which in some instances can lead to actual damage to this organ. However there are a few with different chemical alterations like Primobolan and Proviron which are alkylated at the one position (methyl). In addition to 1 methylation, Primobolan also utilizes a 17 beta ester (acetate) to further protect against reduction to inactive form. While Primobolan and Proviron do not place the same stress on the liver, they are also much less resistant to breakdown than 17 alkylated orals, and are ultimately less active milligram for milligram.
     Oral steroids generally have very short active half-lives of only a few hours, but they also tend to show results very quickly. For that reason it became common practice to use an oral steroid of high potency near the beginning of a cycle as to “boost” gains in the first few weeks. This is known as frontloading. This period is generally only 2 to 4 weeks long depending on the liver toxicity of the compound. The more toxic the compound the shorter the period of usage is. This is to prevent damaging your liver. A milder steroid like Anavar, Proviron or Primobolan is often added towards the end of a cycle. This is done in an attempt to minimize the loss of gains when the main compounds are discontinued. These mild steroids are often extended for a few weeks after the cycle at very low dosages also known as a bridge. The purpose of a bride is to minimize muscle or strength losses in the period between the cycle and PCT. During PCT no steroid should be used as that will hinder recovery of the HPTA axis.
     It is very important to select your choice of steroids according to your goal. Every compound has certain characteristics that make it more suitable to a specific use. For example- Trenbolone is not very good at bulking; however its fat burning properties are outstanding. So that will make it a very attractive addition to a cutting or lean mass cycle. Side-effects of each steroid compound should always be taken into consideration whenever a stack is planned. Never combine compounds that exert similar side-effects. For example- Combining Dianabol and Anapolon can be very dangerous as both are very toxic to begin with and combining them will only worsen their toxicities and that can do serious and irreversible damage.
     Below is a chart you can use in helping to choose your selection of steroids. 10 = Max and 1 = Min

      The dosage used is important in determining the level of benefit received. Anabolic steroids tend to be most efficient at promoting muscle gains when taken at a moderately above therapeutic dosage level. Below this (therapeutic), potential anabolic benefits are often counterbalanced, at least to some extent, by the suppression of endogenous testosterone. At very high doses, smaller incremental gains are noticed. In the case of testosterone enanthate or cypionate, for example, a dosage of 100 mg per week is considered therapeutic, and is generally insufficient for noticing strong anabolic benefits. When the dosage is in the 300-600 mg per week range, however, the drug is highly efficient at supporting muscle growth.             Above this range, a greater level of muscle gain may be noticed, but the amount will be small in comparison to the dosage increase. Below are some commonly used dosages for the steroids listed earlier. Avoid taking the higher end of the dosage range during your first couple of cycles. You will have excellent results from lower dosages during your first few cycles. Lower dosages are also less likely to cause excessive side-effects and give you the opportunity to learn how your body reacts to steroid usage.