Study: testosterone works better than deca

In the late eighties the American army did experiments with anabolic steroids on soldiers. One of the experiments that the army doctors carried out was a comparative study on the effect of deca and testosterone. Which works best? This is what the doctors wanted to know.

Nandrolone [see structure in the diagram left] is almost identical to testosterone [structure shown below]. The difference between the two molecules is that the C19 methyl group is present in testosterone and is absent in nandrolone.


As a result, nandrolone does not convert easily into estradiol and it has fewer feminizing side effects. The absence of the C19 methyl group also means that nandrolone interacts more strongly with the androgen receptor. In animal studies the anabolic effect of nandrolone is higher than that of testosterone. You can read more about nandrolone in the Anabolics Book.

The doctors used thirty healthy and ‘physically active soldiers’ for their study. One of them was a cyclist, nine did weight training and twenty were runners. The doctors divided the soldiers into four groups.

Those in group 1 were given a weekly injection containing 100 mg of testosterone enanthate for a period of six weeks. The preparation used was Delatestryl, made by Squibb. Those in group 2 were given an injection each week containing 300 mg of the same substance.

Those in group 3 were given an injection each week containing 100 mg of nandrolone decanoate. The preparation used was Organon’s Deca-Durabolin. Those in group 4 were given 300 mg of deca each week.

The effects of the testosterone injections are shown below. The second table below shows the effect of the course of deca injections.


Of the light dosage injections (100 mg per week, by today’s standards regarded as a homeopathic quantity by the average chemical athlete), deca works better. One hundred milligrams of deca builds more bulk than one hundred milligrams of testosterone, and breaks down more fatty tissue as well. And the increase in body strength also seems to be bigger.

The three-hundred-milligram per week doses worked better than the hundred-milligram doses. If you compare the results of the two heavier dosages, then testosterone comes out best. The weight increase is approximately the same for both substances – over three kilograms – but the testosterone users lose fat and the deca users do not. What’s more, the effect of testosterone on body strength is greater.

Some of the blood analysis results are shown below. If you want to base your verdict on the side effects of the two steroids on these blood counts, then the only thing you can really say is that there’s not much to choose between them.

B = values at the beginning, D = measurements after six weeks.


The men in the testosterone group had higher concentrations of testosterone and estradiol. It’s pretty clear why that is. The chance of the testosterone users developing gyno is therefore somewhat higher. But on the other hand, we now know that nandrolone is not only an androgen, but also an oestrogen. [J Steroid Biochem Mol Biol. 2004 Jul;91(3):99-109.] Because it has no C19 methyl group, nandrolone also fits in the estradiol receptor.

What is clear is that, certainly at the lower dosage, deca has fewer negative effects on the testes. There is less volume decrease and sperm cell production stays nearer to the normal level. The difference between deca and testosterone is smaller at the 300 mg per week dose.

Based on this study, you can conclude that at non-homeopathic dosages you can expect more effect from testosterone than from deca. You could also conclude that deca is perhaps safer. But recent studies cast doubt on this assertion. In animal studies high doses of nandrolone proved slightly more dangerous for the blood vessels than high doses of testosterone.

Anabolic steroids are made for use in small quantities. If you go for higher dosages, many of the positive characteristics no longer apply. In that case old-fashioned testosterone turns out to be more effective – and maybe also less risky.

Comparison of the effects of high dose testosterone and 19-nortestosterone to a replacement dose of testosterone on strength and body composition in normal men.


We examined the extent to which supraphysiological doses of androgen can modify body composition and strength in normally virilized men. In doubly blind tests, 30 healthy young men received testosterone enanthate (TE) or 19-nortestosterone decanoate (ND), at 100 mg/wk or 300 mg/wk for 6 weeks. The TE-100 mg/wk group served as replacement dose comparison, maintaining pretreatment serum testosterone levels, while keeping all subjects blinded to treatment, particularly through reduction in testicular volumes. Isokinetic strength measurements were made for the biceps brachii and quadriceps femoris muscle groups before treatment and 2-3 days after the 6th injection. Small improvements were noted in all groups but the changes were highly variable; a trend to greater and more consistent strength gain occurred in the TE-300 mg/wk group. There was no change in weight for TE-100 mg/wk but an average gain of 3 kg in each of the other groups. No changes in 4 skinfold thicknesses or in estimated percent body fat were observed. Of 15 circumferences, significant increases were observed only for men receiving TE-300 mg/wk (shoulders) and ND-300 mg/wk (shoulders and chest). The data suggest that high dose androgens increase body mass and may increase strength in normal men but, except for a consistent weight gain with greater than replacement doses, the detectable changes were highly variable and relatively small, especially in comparison to the significant alterations which were observed for other markers of androgen action.

PMID: 1958561 [PubMed – indexed for MEDLINE]

Source: http://www.ncbi.nlm.nih.gov/pubmed/1958561

Subscribe to our Newsletter!

ironmagazine.com Newsletter

Unsubscribe at anytime,  no spam & we do not sell your info!

This will close in 0 seconds

IronMag Labs Andro Creams

This will close in 0 seconds

Muscle Gelz Heal

This will close in 0 seconds