The main reason a testosterone only cycle is recommended for the first time users is because it is the building block of all future cycles - if it isn't - it should be! By using testosterone initially you will get an idea of how your body will react to it. You will need to know if you are prone to gyno , how much fluid you will retain and how much your blood pressure will raise with the use of anabolic steroids as part of your training and nutrition program. These are very important things to be aware of.

Think about it like this - you're doing a stack of testosterone enanthate and dianabol - you feel the signs and symptoms of gyno coming along. So you fix the problem by taking by taking 20-30 mg of Nolvadex or 100 mg of Clomid (which you intelligently kept on hand) daily until the problem subsides and a few days after just to be safe. So the next time you cycle - you use only testosterone enanthate to avoid the aromotization problems brought upon by the addition of the dianabol tabs the first time out. But guess what? It wasn't the test that was aromatizing after all - it was the dianabol. Now with testosterone only, you are still getting the signs and symptoms of gyno and must once again control the substance with use of an anti estrogen. Had you known you were gyno prone with the testosterone you could have better planned this second cycle and worked out a stack to your advantage and possibly even eliminated or greatly reduced the risks of re-ocurring gyno. If you start cycling with a stack, you won't have any way of knowing which steroids are causing which side effects.

Another reason why testosterone only is a good first cycle - it's your first cycle! Why go overkill? You'll grow like a weed off testosterone only with correct nutrition and training - hell, even without it! In a study done by Bhasin and co-workers1, men with no weight training whatsoever made increases in fat-free mass (4KG or 8.8 lbs), increases in triceps mass (400 mm or 1.6"), increases in quadriceps mass (600 mm or 2.4"), and added 10KG (22.2 lbs) on their bench press and 20KG (44.4 to their squat. It's TESTOSTERONE after all. You're injecting HORMONES into yourself. Don't let the quantity fool you - a mL of cyanide will kill you the same way as minimal amounts of steroids will make you grow. Your virgin androgen receptors will eat it up. Why use more when you'll get the same results off less? What's the point? It's just a big waste of time and money. The last thing you want to do is develop a tolerance so that you are required more quantity in the future.

Testosterone may be a strong androgen, but the side effects are very easily controlled for almost all of them with a few simple ancillaries.

With any steroids you take you are going to shut down your natural testosterone production and this can lead to short term impotence and testicular atrophy (short term if your post cycle therapy is sound!). Deca and Trenbolone are not the only ones that cause this (any drug can when not accompanied by testosterone). Deca and Trenbolone are just the most common and most complained about for this type of thing.
Ok so I found this... but I still feel like this doesn't bash my anavar only cycle. I get why test is a good foundation, but i feel like this is more of a rule of thumb.