but I think you are overstating the likely hood of protein powder use leading to steroid use
I wouldn't say protein shakes are a gateway to steroid use.
As I said earlier I work in the fitness industry and many work colleagues and friends are competitive bodybuilders (male and female) and/or previous competitors who now coach clients to the stage. I also have a few friends that own guns in my area.
The reason there is a link is due to some peoples (mainly young men) lack of knowledge.
These young men go to the gym a bit and lift weights a bit. Drink protein shakes everyday and expect their muscles to magically bulk. When that doesn't happen they start looking round for alternatives. Rather than educating themselves on how to eat right and bulk correctly. It's a quick fix.
I can tell you that everyone I know in my work life and social life feel steroid use in young men is going up at a big rate and they are all approached a lot to find out what steroids they use.
Body building is largely unregulated. Many on stage are using.
For me it's a similar path as EDs. They are determined to get the 'perfect body' asap and go to extremes. The same as the young girls you see in the papers who are so desperate lose weight they buy illegal slimming pills of the Internet and end up sick or worse.
Steroid use is on the rise.
Protein shakes don't lead to steroid abuse. I would however be doing my best to educate my kids if they decided to start adding protein shakes into their diets. My kids are both athletes, so are quite well educated on sports nutrition. If they were fluffing protein shakes with little exercise I would be concerned.
I have actually known young men at dds school (I say young men they are 6th form) simply drink protein shakes with every and complain they aren't getting any muscle.
Proteins shakes are advertised as a magic solution and that if you drink these you will look like this model. Similar to how slimming tablets are touted. That is the problem, imo.