Did the Ludovico technique work on Alex or was he just faking all the time?

After being released, he is attacked by vagrants. I believe that if he was faking, he would have defended himself. Instead, two bobbies come along and save him. They turn out to be his old "droogs" Dim and Georgie who then also beat him up. I believe that if he was faking then he would have tried to protect himself.

If he was faking about being "cured" and being non-violent, was he also faking about Beethoven music making him ill? Because that drove him so mad he attempted suicide by jumping out a window, seriously injuring himself. I think if he had been faking his cure he would not have gone to such extreme lengths to prove it.

Also, as I mentioned in commenting on djmadscribbler's answer, he was nearly drowned by his old friends Dim & Georgie because he was unable to fight back. So there were 2 instances where Alex would have put his life in jeopardy just to fake the effectiveness of the treatment. For that reason, I think the treatment really did effect him and he wasn't faking.

I'm of the opinion Kubrick changed the story so that in the movie, Alex was faking that the conditioning worked.

Basically I was convinced by the case made by this analysis from a guy named Rob Ager. Here's a key excerpt:

In the book Alex spouts his own objection as the preacher and Minister debate the morality of the Ludovico technique, “Me, me, me. How about me? Where do I come into all this? Am I just like some animal or dog? … Am I just to be like a clockwork orange?” The last line in particular is crucial to the book’s themes, but Kubrick omitted it entirely. In Kubrick’s rewrite Alex fakes his sickness response, burps as he sits up (which he can do at will, as demonstrated during the police interrogation scene) then asks “Was it alright? Did I do well sir?” He knew perfectly well what was expected of him and he acted his part accordingly.

This indirect mutual agreement between Alex and the Minister was also communicated through a short verbal interraction in the prison courtyard. In the book Alex objects to the minister's statements and is in turn chosen for the Ludovico treatment. Kubrick drastically alters this interraction by having Alex lie that he was imprisoned for "the accidental killing of a person". The Minister is impressed with his ability to lie outright and responds "Excellent. He's enterprising, aggressive, outgoing, young, bold, viscious. He'll do."

Why would the Minister need a criminal who is "enterprising"? Because Alex is the type of lying opportunist who will pretend to go along with the Ludovico program, which will mutually benefit the Minister's aim of clearing out prisons to make space for political offenders. Cutting down crime is merely an illusion he needs to fabricate to justify this policy and Ludovico is the propaganda tool he needs. Alex then responds by thanking the Minister for choosing him (this didn't happen in the book). The Minister responds "Let's hope you make the most of it my boy." He's basically telling Alex to put on the best act he can for the doctors and the press.

Once released Alex finds that his old, comfortable life is no longer available to him. In his parents’ flat he is unphased by the erotic female portraits on the walls - shouldn't he be feeling ill as he did with the woman on the stage? And he gives away his unchanged aggression by swinging a fake punch near his father’s face, “Keeping fit?” he asks. Where is his Ludovico aversion to violent impulse?

In the book, Alex is hooked up to a brain monitor and his brain's activity is watched. The people conducting the experiment can see clearly that he is having a response to the treatment. You may be able to trick people but not a brain monitor.

I thought Alex was faking his cure, but I thought his sickness was real when he heard the 9th. I believe Alex was faking because before he signed up for the treatment he was the model prisoner, and wanted out, even if it meant he would have to stop his violence. I also think the fake burp is very note worthy, as well as the minister choosing Alex because he was enterprising.

The reason why I think the music made him sick was because it was so near and dear to him. He literally got off on the 9th, and would celebrate his violent evenings by listening to the 9th after he got home. After the treatment, he wanted to fake being cured, but he couldn't fake the fact that he loved the 9th and associated it with ultra violence, which he could not commit anymore. Also, if the treatment really did work, why would it just be that song that caused a negative reaction and not other songs?

I think given the choice; Be yourself and stay in jail, or be fake and be free was too much for Alex...which caused him to jump.

As far as him "being cured" at the end...I just simply can't understand it. They hint at the fact that he had a lobotomy...but I don't think he was finally "cured" until he spoke with the Minister, and it was conveyed to him that they want him to go back to what he was...for their own political survival.

I really don't know to be honest. But this is the take I had on the film. And I've never read the book, so there is that too.

I think that Alex maybe was faking his aversion to sex and violence, but he was NOT faking his aversion to the 9th. There wouldn't be any need for him to fake it, for a start. Aversion therapy has been used in the past but the results were mixed at best, and Alex being conditioned against the 9th clearly wasn't part of the plan. The newspapers had proclaimed him 'cured' of his violent impulses, so he would've had to fake it in the company of other people, but we see him singing in the bath and apparently fantasizing about the attack two years before and he's completely comfortable. He was alone during that scene, with no one around to see him and have his cover blown. Yet later, he does say that the 9th made him feel like dying, even though, like I said, it wasn't part of the plan, so there would've been no need for him to fake that. Later, when they torture him with it, there's no one around to see him, yet he was quite clearly in excruciating pain. All this evidence piled up together makes the idea of a false aversion to the 9th hard to swallow.