Yes and no. Different steroids have a ratio of anabolic(muscle building) to androgenic(masucline making) activity. i.e. Some will give you a big beard with little muscle, or a lot of muscle and a little beard. Most female body builders try to use steroids that have tilt more towards anabolic over androgenic activity. This usually isn't testosterone, this is usually drugs like oxandrolone, boldenone, nandrolone, or the more recent SARMs. Thus they can reduce the masculinization of their bodies while still putting on lots of muscle.

I’m sure they do at the very very extreme of competitions, but even a tiny bit of testosterone has largely unwanted side effects for women. (I am hedging with “largely” there, as there’s a whole gender identity thing to wade into.)

More common:

Oral anavar. Frequently used. Easily available in 5mg pills, actively marketed as “lady Var”. Anavar is generally regarded as a “mild” steroid, and was actively and usefully prescribed for a time. However, I’ve known women who have done anavar, and there’s such a range of variability in how they respond. I know a woman who was taking the 5mg dosage and fairly quickly had her voice start to drop. (Caveat there: who knows if the underground steroids are properly dosed.)

Oral turanibol. Queue the East German national anthem, this was the drug of choice for the Lovely Ladies Behind the Iron Curtain. Though nobody actually told them it was a steroid. “Vitamins”, per the Soviets, vitamins that literally put hair on your chest. Same caveats as anavar, and I never actually see turanibol marketed for women now.

Nandrolone phenylpropionate (NPP). The short-acting version of deca, the very well-known steroid. This compound was actively developed for women, and truly successfully used in clinical scenarios, especially in regards to cancer-related wasting, and osteoporosis, before we had better drugs. Very low androgenic properties, but quite the literal pain the ass, as you have to inject every day.

They do, albeit in much lower dosages to avoid or at least reduce the androgenic effects (hair/genital growth, voice deepening) of testosterone. Usually steroids with a better anabolic/androgenic profile are taken in addition or instead of testosterone.

Of course, there's also a small subset of female bodybuilders that lean into steroids to an extent to essentially chemically transition and I wonder if many of these might just be trans without noticing or disclosing it. As an additional caveat, in some places it can also be significantly easier to live as a woman on a lot of steroids than a trans man.

Testosterone is popular among women as well. Injections are in general safer than oral (because of liver health). Most women start with Anavar though as the risk of developing masculine features is reduced with it and the pill form makes it more palatable for many beginners.

Most fitness girls/celebs/models probably stop at Anavar as keeping feminine features is very important for them.

There is even a term for it in the fitness world. "Anavar girls". It's widely popular.

Yes.

The Ms. Olympia bodybuilding competition just returned last year, after going away for the previous five years.

The large amounts of muscle the woman had to put on had basically fallen out of style with fans, and they e basically replaced it with “fitness” classes for the women competitors.

yes