Of course! He uses steroids! His language is far from convincing when talking on the topic of his ‘natural status’. He tends to look bloated from his midsection and his lower half (especially calves) are very disproportionate to his top half.
These factors are enough for me to give steroids verdict.
Also, USADA’s drug-testing protocol’s remain to be fairly weak, due to certain loopholes that can be taken by clever fighters, causing them to slip through the net. For example,
buy sarms is a one method athletes can use, is to say at the test that they’ve taken a certain supplement or medication… which if “tampered”, or it contains banned substances unknowingly - they can get let off the hook and avoid a suspension. Coincidentally, Costa did just that, by saying he took “stomach medication”.