Winstrol in particular is known for exhibiting some profound negative cholesterol changes in humans as evidenced by some clinical studies. Winstrol administered orally at just 6mg daily for a 6 week period resulted in a reduction of HDL by 33%, alongside an LDL increase of 29% (all test subjects were healthy males engaged in regular physical exercise)  . Even the injectable Winstrol preparation has demonstrated to produce negative cholesterol profile changes. Only a single 50mg dose of injectable Winstrol was administered to 12 healthy test subjects, and resulted in significant HDL reduction with an increase in LDL (these negative cholesterol changes remained for a 4 week period following administration before returning to normal values)  .
An important consideration when planning a steroid cycle, in particular the timing of dosing to be administered, is the active half-life of the drug being employed. The half -life may be defined as the time (t) the level is half of the starting level of a given compound; at time 2t, the level is a quarter of the starting level, and at time 3t, the level is an eighth of the starting level, and so on.
This information is vital in the timing of the dosing when attempting to achieve a more stable blood concentration, which leads to greater overall results and maintenance of gains. Some fluctuations of concentration levels are acceptable, and are also mostly unavoidable, but should be kept to a minimum.
Basically every drug has a half life, steroids included. If for example, you were to inject 200mg of Decadurabolin once weekly, for 6 weeks, how would you know when you were "off"? Would you be "off" when you had finished your last dose? You would be able to calculate this from the half life of Deca. The half life of Deca is around 14 days. This means that 14 days from your last shot of 200mg of Deca, your blood levels of Deca will contain 100mg of the steroid. Another 14 days from then, . 28 days from last dose, your blood levels will contain 50mg of the steroid. This amount then keeps halving every 14 days. Therefore you can clearly see that when you finish your cycle, even though you are not putting any steroids into your body, you may think that you are now "off", however you still have, and will still have for some time after your last dose, "active" blood levels of the steroid. Therefore you can plan what to use, how long for, and how long off your cycle, based on these half life's.