Here is what I found on the old school high dose test.
SHORT DESCRIPTION: Test 400 is a mexican version of Testoviron, but in a lot higher dosage. Usual dosages is one 400 mg per week.
Test 400 is obviously simply a marketing trick for novice bodybuilders. mixture of Eanthate and Cypionate is pointless as they both release at the same time. The dose of 400 mg forced the manufacturer to introduce more alcohol into thy product which results in painful injections. Combined with classic testosterone side effects this is definitely not the best product out there.
LONG DESCRIPTION: Denkall's Test 400 wins the prize for the absolute highest concentration for any steroid in one milliliter of oil. Measuring in at an unheard of 400 milligrams, this product is nothing short of a shocking new addition to the high-dosed veterinary steroid market in Mexico. Test 400 is a blended product, with each milliliter containing 25 milligrams of testosterone propionate, 187 milligrams of testosterone cypionate and 188 milligrams of testosterone enanthate. In order to achieve such a high concentration of steroid it appears that the amount of alcohol used in the solution has been markedly increased. Without increasing the alcohol level 400 milligrams of steroid would simply be too much for the solution to dissolve. The steroid hormone is more soluble in an oily solution with heightened amounts of alcohol, which allows us to achieve a dosage otherwise not possible. The drawback however is that the alcohol makes for an irritating, almost caustic solution to inject. Users commonly report strong irritation and pain at the site of injection, in many instances requiring the user to dilute the steroid with lower dosed oil based products if Test 400 is to be continued. But for those solely interested in maximum dosage, or those willing to later dilute a steroid in order to purchase the most steroid in single vial possible, Test 400 looks like an instant winner.
The design of this steroid most closely resembles that of Testoviron, containing a mix of rapid and medium/slow acting esters. In fact the only difference between the enanthate/propionate blend Testoviron and Test 400 are the dosages of the esters, and the addition of testosterone cypionate. I see no real advantage in stacking testosterone cypionate with enanthate though, as the pharmacokinetics of these two esters are literally identical. Testosterone levels peak and drop in parallel with these two agents, with no visible distinction. Upon closer investigation we see that the only advantage to adding cypionate appears to be a marketing one, as we have a product with three steroids instead of two. At least with Sustanon the release parameters are different with each ester, such that an attempt is made to integrate the four and support the balanced release of testosterone. But with test 400, having propionate and all cypionate would be totally indistinct from having propionate and all enanthate.
The effects of Test 400 would be similar to that of all testosterones. Testosterone is one of the best mass-building agents, so users can expect substantial gains with this product. Testosterone is also strongly estrogenic and androgenic however, so one should expect these gains to be accompanied by equally strong side effects. This includes water retention, possible fat increases and even gynecomastia is estrogenic levels get too high, and acne, oily skin and possible hair loss from the androgenic component of this steroid.
It wasn't the esters in it that cause the pain it is the alcohol content, more had to be used to dissolve the hormone. The prop at 25mg isn't going to do anything for the user, especially if the user is only going to shoot 1ml a week split into two shots(1/2ml, 1/2ml). Using esters that release at the same time is pointless and used just so that people will see more tests in it and buy it simply because of that.
So what is done differently now with the super high dose gear that wasn't done back then to make the shots painless at that high of dose? It isn't the esters in it and it isn't melting points, it has to be something to do with solvents and cosolvents and the way its brewed.