Testosterone-replacement therapy does some gnarly things to a man's body. Namely, it speeds up the growth of pre-existing cancerous cells and can cause infertility. Fortunately young, healthy men can naturally keep their T levels in check. 

Here are the four things you need to steer clear of.

1. Heated plastics

Plastics contain a lot of chemicals that work as estrogen mimetics and can be bad for your T, says Brian St. Pierre, CISSN, C.S.C.S., of Precision Nutrition. When heated, plastics can release phthalates and BPA—both bad.

2. Products labeled “high fragrance”

The label “fragrance” means it contains “a phthalate compound,” says St. Pierre. “Your skin is your largest organ, and it absorbs what is put on it.” Look for phthalate-free soaps and deodorant.

3. Excessive booze

“Yes, consistent heavy drinking lowers your T,” says St. Pierre. For the record, it’s the ethanol that hurts, but that doesn’t mean you have to cut it out completely. “Have limits,” says St. Pierre, advising a max of one to two drinks per day.

4. Painkillers

Men who are on chronic-pain meds (especially opioids like oxycontin) can have super-low testosterone. According to Abraham Morgentaler, M.D., “Some of these guys have the lowest T we see—it’s a poison for the hormone system.”

Also mix in these 5 testosterone-boosting workouts into your regimen and read up on these 3 supplements that can naturally boost T levels