OPINION ON APPELLANT’S PETITION FOR DISCRETIONARY REVIEW
W.C. DAVIS, Judge.A jury convicted appellant of delivery of a controlled substance and assessed punishment at confinement for 25 years. The Court of Appeals affirmed the conviction. Stewart v. State, 693 S.W.2d 11 (Tex.App.—Hous. [14th] 1985). We granted appellant’s petition for discretionary review to address his contention that the evidence is not sufficient to support a conviction for delivery by offer to sell where the substance offered was not a controlled substance.
On February 5, 1982, appellant approached Houston undercover police officers W.C. Pudifin and D.C. Duke in Rachel’s Lounge, a bar known as a place for drug dealing. Pudifin asked appellant if he “got anything.” Appellant replied that he had some heroin, a hundred dollar bag. Appellant showed the officers a brown powdery substance that they believed was heroin. Pudifin paid appellant $100 and received the substance. Appellant was later arrested.
The substance was tested and found not to be heroin. The officers did not know what it was. But, they testified that it was not a controlled substance. Pudifin also testified that a hundred dollar bag is a small quantity, a little over a gram. The substance appellant sold Pudifin weighed one gram.
Appellant was charged under V.A.C.S., Art. 4476-15, §§ 4.03 and 1.02(8) with delivery of a controlled substance by offer to sell.1 Appellant contends that because the substance delivered was not a controlled *288substance the evidence is insufficient to support his conviction. Appellant argues that the enactment, in September 1988, of Art. 4476-15b, entitled “Simulated Controlled Substances,” shows that the legislature intended that the Controlled Substances Act cover behavior involving controlled substances and not cover acts involving simulated controlled substances.
Art. 4476-15b, § 1 states:
(2) ‘Deliver’ or ‘delivery’ means the actual or constructive transfer from one person to another of a simulated controlled substance, whether or not there is an agency relationship. For the purposes of this Act, it also includes an offer to sell a simulated controlled substance. Proof of an offer to sell must be corroborated by a person other than the offeree or by evidence other than a statement of the offeree.
(4) ‘Simulated controlled substance’ means a substance that is purported to be a controlled substance, but is chemically different from the controlled substance it is purported to be.
Sec. 2(a) states in part:
A person commits an offense if the person knowingly or intentionally manufactures with the intent to deliver or delivers a simulated controlled substance and the person:
(1) expressly represents the substance to be a controlled substance;
(2) represents the substance to be a controlled substance in a manner that would lead a reasonable person to believe that the substance is a controlled substance; or
(3) states to the person receiving or intended to receive the simulated controlled substance that the person may successfully represent the substance to be a controlled substance to a third party-
The elements of an offense under § 4.03 are (1) a person (2) knowingly or intentionally (3) delivers (4) a controlled substance. Under § 4.03 when delivery is by actual or constructive transfer the substance must be proved, usually by its chemical properties, to be a controlled substance. However, when delivery is by offer to sell no transfer need take place. A defendant need not even have any controlled substance. All he need do, as appellant did, is state that he had a hundred dollar bag of heroin he would sell to the officers.2 The offense is complete when, by words or deed, a person knowingly or intentionally offers to sell what he states is a controlled substance. Therefore, the fact that the substance is later found not to be a controlled substance does not render the evidence insufficient to prove the offense of delivery by offer to sell a controlled substance. The element of “controlled substance” is proved by appellant’s statement offering to sell heroin.
In order to commit an offense under art. 4476-15b, (1) a person must (2) knowingly or intentionally (3) deliver (4) a simulated controlled substance; and (5) must expressly represent the substance to be a controlled substance and (6) represent the substance to be a controlled substance in a manner that would lead a reasonable person to believe that the substance is a controlled substance; or (7) state to the person receiving or intended to receive the simulated controlled substance that the person may successfully represent the substance to be a controlled substance to a third party. Under art. 4476-15b, as with § 4.03, where delivery is by actual or constructive transfer, in order to be an element of the offense, the substance must be, by its chemical properties a simulated controlled substance, usually determined by analysis of its chemical properties. In order to commit the offense of delivery by offer to sell, a person would have to offer to sell “a simulated controlled substance” and yet also represent the substance to be a controlled substance so that a reasonable person would believe it to be a controlled *289substance. If a person offers to sell what they state is a simulated controlled substance obviously he cannot also meet the elements (5) and (6) listed above, representing it to be a controlled substance. Thus, it would seem to be an impossibility to commit the offense of delivery by offer to sell under art. 4476-15b, § 2(a)(1), (2). However, it might be possible to commit such offense under art. 4476-15b, § 2(a)(3). Under this provision if a person offered to sell what they told the buyer was a simulated controlled substance and told the buyer that he could represent the substance as a controlled substance to a third party, that person could be guilty of offering to sell a simulated controlled substance. But, if, as in the instant case, appellant intentionally or knowingly offers to sell a controlled substance the provisions for offer to sell under art. 4476-15b would not apply, even if the law had been in effect at the time. The fact that the substance is found to be a simulated controlled substance goes to negate intent. It is a defense.
The elements “controlled substance” and “simulated controlled substance” must be proved in a prosecution under the respective statutes. When actual or constructive delivery is involved the nature of the substance, usually determined by chemical analysis, is thus necessary of proof. When the prosecution involves delivery “by offer to sell” that element can be met by the representation, by word or deed, that the person has a controlled substance to sell. The chemical properties or indeed, the presence or possession of any substance is not necessary to the offense. In the instant case the offense was complete when appellant stated that he had a hundred dollar bag of heroin to sell. He named a “controlled substance” in his offer and the offense was complete. Cf. United States v. Roman, 728 F.2d 846, 859-860 (7th Cir.1984) where the court noted that the defendant was charged with conspiracy to distribute L.S.D. and not with distribution of L.S.D. so that the identity of the substance did not matter; cf. United States v. Pietri, 683 F.2d 877 (5th Cir.1982).
In sum, the subsequent enactment of art. 4476-15b does not affect appellant’s conviction. The State proved all of the elements necessary to show commission of the offense of delivery by offer to sell of heroin under art. 4476-15, § 4.03. We need not decide whether, under the evidence which shows delivery by actual transfer of a simulated controlled substance under art. 4476-15b, appellant could have been prosecuted for a first degree felony offense under the Controlled Substances Act for delivery by offer to sell, if the Simulated Controlled Substances Act had been in effect at the time. The contention is overruled and the judgment of the Court of Appeals is affirmed.
. Sec. 4.03(a) [currently § 4.031] states:
Except as authorized by this Act, a person commits an offense if he knowingly or intentionally manufactures, delivers, or possesses with intent to manufacture or deliver a controlled substance listed in Penalty Group 1.
Sec. 1.02(8) as effective at the time appellant was prosecuted stated:
‘Deliver’ or ‘delivery’ means the actual or constructive transfer from one person to another of a controlled substance or drug paraphernalia, whether or not there is an agency relationship. For purposes of this Act, it also includes an offer to sell a controlled substance or drug paraphernalia. Proof of an offer to sell must be corroborated by a person other than the offeree or by evidence other than a statement of the offeree. (Emphasis added).
. We recognize that had appellant not stated or shown any amount, prosecution under § 4.03 might well be impossible. Such a case is not before us. We do not address speculative instances.