Anabolic Steroid cycle transforms acne bacteria into super-acne bacteria

The use of anabolic steroids stimulates the growth of Propionibacterium acnes, which increases the chances of developing acne. Researchers in Iran discovered this and we wrote about it recently. But having dug up an old study done by the dermatologist Csaba Kiraly did in 1988, we reckon this is not the whole story. That study suggests that steroids use changes Propionibacterium acnes from ordinary pimple bacteria into rampant acne bacteria.

Propionibacterium acnes
Kiraly took small samples of skin tissue from the forehead and back of 7 male chemical bodybuilders and extracted the bacteria from them. The researcher took samples just before they started a cycle of steroids [Week 0], halfway through the course [Week 4] and on the last day [Week 8].

The researchers did an experiment with 20 male students, all of whom had been doing strength training for a couple of years. They put the men through their paces with leg training exercises: squats, dead-lifts and split-squats.

The doses – in mg per day – are shown below. By contemporary standards the doses are modest. Despite this, the effects on lean body mass and fat percentage were not much different from the effects that steroids users report nowadays.


Kiraly found a total of 44 different strains of Propionibacterium acnes – plus 2 strains of Priopionibacterium avidum. In his laboratory he then measured the activity of a number of bacterial enzymes which may be involved in the development of acne.

To start with Kiraly looked at lipase, an enzyme that splits fat into fatty acids and glycerol. Propionibacterium acnes uses that enzyme to make the environment so acidic that other, benign bacteria can’t survive. Kiraly found no statistically significant effects of steroids use on this enzyme.


Kiraly did find statistically significant effects of steroids use on the enzyme hyaluronidase. That enzyme makes the fibres of connective tissue supple and permeable. Propionibacterium acnes uses hyaluronidase to embed itself in the skin.


The figure above shows that Propionibacterium acnes started to produce more hyaluronidase during the steroid cycle. That probably means that the bacteria can penetrate more deeply into the skin, form new colonies more easily and are more difficult to combat.

Reading between the lines you can see that Kiraly suspects that the effect he discovered plays a role in the development of acne while using steroids. He’s not completely sure though – he couldn’t establish a relationship between increased activity of hyaluronidase and actual acne. But that may be because of the small number of subjects in his experiment.

Kiraly did not investigate how steroids induce Propionibacterium acnes to start producing more hyaluronidase.