Everyone said it was sweat. After five body washes, I finally realized it wasn't.

1. It's not the sweat

I trained in a hoodie so nobody would see my back.

Sweat and tight shirts can make it worse. But every guy at my gym sweats, and they aren't all hiding their backs.

What matters more is how much oil your skin makes. A lot of that comes from inside, including hormones like testosterone.

2. More showers and body washes didn't fix it

Showered straight after every session. Clean shirt every time.

Then five body washes. Each one bought me a good week or two. Then the spots came back in the same places.

If washing it off was the answer, it would have worked by the fifth bottle.

This is what I did instead.

3. Your gym stack and diet aren't the whole story

Whey. Pre-workout. Creatine. I cut them one at a time. My back looked the same.

Then food. Clean all week, fast food and energy drinks on busy days. Blood sugar swings can feed into hormones and inflammation, and both can show up on your skin.

More than half the guys who took BreakoutLabs' skin quiz lift 3+ times a week. Cutting powders is a guess. It doesn't show you what's inside.

4. Stress and short sleep show up too

Long weeks at work. Six hours of sleep if I was lucky.

Stress hormones can push your skin to make more oil. So a rough month at work can show up on your back and chest.

Almost 6 in 10 guys who took the quiz said work is their main stress. No body wash touches that.

5. You've never actually looked inside

Washes, cutting whey, eating cleaner. All guesses.

What I finally did was one at-home blood test that looks at your hormones (including testosterone), stress, blood sugar and nutrients together. For the first time, I could see what was going on.

About 1 in 4 of the men 19 to 44 that BreakoutLabs has tested were low in vitamin D. The mirror can't show you that.

This is the test.