# Lanham Act Section 43(a): False Designation and False Advertising

> Lanham Act 43(a) explained: false designation of origin, unregistered marks, trade dress, false advertising, Lexmark standing, Dastar, and Romag.

Guide  |  Author: Lidiia Levitska  |  Source: Intellectual Property Law (outsideipcounsel.com)
Canonical: https://outsideipcounsel.com/guides/lanham-act-section-43a/


<div class="quick-answer">
<strong>Quick answer:</strong> Section 43(a) of the Lanham Act, codified at [15 U.S.C. § 1125(a)](https://www.law.cornell.edu/uscode/text/15/1125), is the federal unfair competition statute. It creates two distinct claims: **§ 43(a)(1)(A)**, false designation of origin, reaches uses of any word, name, symbol, or device likely to cause confusion about affiliation, sponsorship, or origin, and it is how unregistered trademarks and trade dress are enforced federally; **§ 43(a)(1)(B)**, false advertising, reaches commercial advertising that misrepresents the nature, characteristics, qualities, or geographic origin of goods or services. Standing requires a commercial injury within the statute's zone of interests, proximately caused by the deception (*Lexmark v. Static Control*). "Origin" means the producer of the physical goods, not the author of the ideas inside them (*Dastar*). Remedies under § 35(a) include profits, damages, and fees in exceptional cases, with willfulness a weighty factor but not a prerequisite for profits (*Romag*). This is general education, not legal advice.
</div>

No registration certificate? You still have a federal claim. Section 43(a) is the Lanham Act's open door: the provision competitors use against knockoff packaging, copied product looks, fake affiliation claims, and lying comparative ads, all without a registered mark in sight. It is probably the most-litigated sentence in trademark law, and the Supreme Court has spent the last two decades marking its boundaries: who may sue, what "origin" means, and what a winner collects. This guide walks both prongs and all three landmark cases. It sits within our pillar on [how to trademark your business](/guides/how-to-trademark-your-business/), which covers why registration is still worth it even though § 43(a) exists.

## What does Section 43(a) actually say?

The statute imposes civil liability on "any person who, on or in connection with any goods or services... uses in commerce any word, term, name, symbol, or device, or any combination thereof, or any false designation of origin, false or misleading description of fact, or false or misleading representation of fact, which:

- **(A)** is likely to cause confusion, or to cause mistake, or to deceive as to the affiliation, connection, or association of such person with another person, or as to the origin, sponsorship, or approval of his or her goods, services, or commercial activities by another person, or
- **(B)** in commercial advertising or promotion, misrepresents the nature, characteristics, qualities, or geographic origin of his or her or another person's goods, services, or commercial activities."

The action lies in favor of "any person who believes that he or she is or is likely to be damaged by such act," language the Supreme Court has since disciplined (below). Subsection **(a)(3)** adds one more rule for civil actions over **unregistered trade dress**: the person asserting protection "has the burden of proving that the matter sought to be protected is not functional."

Prong (A) is a *confusion* tort; prong (B) is a *deception* tort. Keeping them straight decides pleading, proof, and remedies.

## Prong one: false designation of origin and unregistered rights

Section 43(a)(1)(A) is the enforcement vehicle for **unregistered marks**. If you have been using a distinctive name or logo in commerce, you can sue a confusing imitator in federal court under essentially the same likelihood-of-confusion analysis applied to registered marks; the walk-through for that situation is [someone is using my business name](/guides/someone-using-my-business-name/). The claim also covers **false endorsement and false affiliation**, which is why celebrities and brands use it against implied-sponsorship advertising.

It is also the home of federal **trade dress** protection: product packaging, restaurant decor, and product configuration. The Supreme Court's guardrails:

- ***Two Pesos v. Taco Cabana*, 505 U.S. 763 (1992):** inherently distinctive trade dress (there, a restaurant's festive trade dress) is protectable under § 43(a) **without** proof of secondary meaning.
- ***Wal-Mart v. Samara Brothers*, 529 U.S. 205 (2000):** product **design**, as opposed to packaging, is never inherently distinctive; a design plaintiff must prove secondary meaning.
- **Functionality, § 43(a)(3):** for unregistered trade dress, the plaintiff bears the burden of proving the claimed features are not functional. A feature essential to use or purpose, or affecting cost or quality, belongs to competition, not to one seller.

The elements, evidence, and strategy of a trade dress case are covered in [what is trade dress](/guides/what-is-trade-dress/).

**The *Dastar* limit.** In [*Dastar v. Twentieth Century Fox*](/blog/dastar-v-twentieth-century-fox-reverse-passing-off-origin/), 539 U.S. 23 (2003), the Supreme Court held that "origin of goods" means **the producer of the tangible goods sold**, not the author or creator of the ideas or communications embodied in them. Dastar copied a public-domain TV series onto its own videotapes and sold them as its own product; because Dastar really was the producer of the tapes, there was no false designation of origin. The holding forecloses using § 43(a) as a plagiarism or attribution statute, especially for public-domain content, because that would create what the Court called a species of perpetual patent and copyright. Claims about *who created* content are barred; claims about *what a product is* may still proceed under prong (B).

## Prong two: false advertising

Section 43(a)(1)(B) federalizes false advertising between market participants. The working elements, as courts have distilled them: a **false or misleading statement of fact** (not opinion or puffery) about the defendant's or the plaintiff's goods, made in **commercial advertising or promotion**, that **deceives or tends to deceive** a substantial audience segment, is **material** to purchasing decisions, travels in interstate commerce, and causes or is likely to cause **injury** to the plaintiff.

The key evidentiary fork: a **literally false** statement lets courts presume consumer deception, while a literally true but **misleading** statement generally requires extrinsic evidence, usually a consumer survey, showing actual deception. Comparative claims ("tests prove ours outperforms theirs") are the classic battleground, and establishment claims fail if the cited tests do not support them.

**Standing after *Lexmark*.** The phrase "any person who believes that he or she is or is likely to be damaged" reads limitlessly, and in [*Lexmark v. Static Control*](/blog/lexmark-v-static-control-lanham-act-false-advertising-standing/), 572 U.S. 118 (2014), a unanimous Court replaced three competing circuit tests with a two-part statutory rule: the plaintiff must (1) fall within the Lanham Act's **zone of interests**, meaning an injury to a *commercial* interest in reputation or sales, and (2) show that injury was **proximately caused** by the deception, ordinarily because consumers deceived by the defendant withheld business from the plaintiff. Direct competition is not required (Static Control was a component supplier, not a cartridge seller), but **consumers cannot sue**: a misled buyer's injury is not a commercial interest in reputation or sales.

## What can a winning plaintiff recover?

Remedies for a § 43(a) violation come from Sections 34 and 35 of the Act. Injunctive relief is the workhorse. Under [15 U.S.C. § 1117(a)](https://www.law.cornell.edu/uscode/text/15/1117), a prevailing plaintiff is entitled, "subject to the principles of equity," to recover **(1) defendant's profits, (2) any damages sustained by the plaintiff, and (3) the costs of the action**, with reasonable **attorney fees in exceptional cases**. In assessing profits, the plaintiff proves only the defendant's sales; the defendant must prove its deductible costs. The court may adjust awards up to treble damages, as compensation and not a penalty.

The modern rule on mental state comes from [*Romag Fasteners v. Fossil*](/blog/romag-fasteners-v-fossil-willfulness-profits/), 590 U.S. 212 (2020): **willfulness is not an absolute precondition** to a profits award for a § 1125(a) violation. Congress conditioned profits on willfulness explicitly for dilution claims under § 1125(c) and conspicuously not for § 1125(a), so courts may not import that gate. But the Court and concurrences were equally clear that the defendant's state of mind remains "a highly important consideration": innocent infringers retain a powerful equitable argument against disgorgement, and willful ones effectively guarantee it. Post-*Romag*, the expected value of confusion and false advertising claims rose, which shows up first in demand letters; both sending and answering them is covered in [trademark cease and desist letters](/guides/trademark-cease-and-desist-letter/).

## How the pieces fit: choosing and framing a 43(a) claim

| Situation | Claim | Watch out for |
| --- | --- | --- |
| Competitor uses a confusingly similar unregistered name or logo | § 43(a)(1)(A) false designation | Prove your priority and distinctiveness; no registration presumptions |
| Copied packaging or product look | § 43(a)(1)(A) trade dress | Functionality burden (§ 43(a)(3)); secondary meaning for product design (*Wal-Mart*) |
| Implied endorsement or affiliation | § 43(a)(1)(A) false association | Confusion evidence; First Amendment limits for expressive works |
| Copied creative content sold without credit | Usually **not** 43(a) | *Dastar*: attribution is copyright's domain |
| Lying comparative or performance ads | § 43(a)(1)(B) false advertising | Literal falsity vs. misleadingness; materiality; surveys; puffery |
| Consumer harmed by false ads | No 43(a) claim | *Lexmark*: consumers lack a commercial injury; FTC and state consumer laws apply |

Two boundary notes. First, § 43(a) coexists with state unfair competition statutes (like California's UCL) and common law passing off; plaintiffs routinely plead them together. Second, registration still matters: § 43(a) gives unregistered rights a cause of action, but registration adds presumptions, constructive nationwide priority, incontestability, and counterfeiting remedies, which is why serious brands do both.

Decisions applying all of this are collected in our [unfair competition case archive](/topics/trademarks/unfair-competition/).

## The bottom line

Section 43(a) is federal unfair competition law in one sentence: prong (A) polices confusion about source, sponsorship, and affiliation, and gives unregistered marks and trade dress their federal cause of action; prong (B) polices material deception in commercial advertising. The Supreme Court's trilogy defines its edges: *Lexmark* limits plaintiffs to commercial injuries proximately caused by the deception, *Dastar* keeps authorship and attribution disputes out of trademark law, and *Romag* makes an infringer's profits available without a willfulness gate while keeping intent at the center of the equities. If a competitor is confusing your customers or lying about your products, this is the statute you are suing under; frame the claim on the correct prong and build the evidence that prong demands.

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*This guide is for educational purposes only and is not legal advice. IP outcomes turn on specific facts; talk to a licensed attorney about your situation.*


## Frequently asked questions

### Can I sue under the Lanham Act without a registered trademark?

Yes. Section 43(a)(1)(A) creates a federal claim for false designation of origin that protects unregistered marks, trade names, and trade dress, so long as the designation is distinctive and used in commerce. The Supreme Court confirmed in Two Pesos v. Taco Cabana that inherently distinctive unregistered trade dress is protectable under 43(a) without proof of secondary meaning, and courts apply essentially the same likelihood-of-confusion analysis used for registered marks. What you give up without a registration: the presumption of validity and ownership, nationwide constructive notice, incontestability, and access to counterfeiting remedies. You also carry the burden of proving your rights, including non-functionality if you assert trade dress under 43(a)(3).

### What must I prove for false advertising under 43(a)(1)(B)?

Courts generally require: a false or misleading statement of fact about the defendant's or another's goods or services in commercial advertising or promotion; that the statement either is literally false or actually deceives or tends to deceive a substantial segment of the audience; materiality, meaning the deception is likely to influence purchasing decisions; interstate commerce; and injury or likely injury to the plaintiff, such as diverted sales or lost goodwill. A literally false statement lets courts presume deception; a merely misleading one usually requires consumer survey evidence. Puffery, meaning vague superlatives no reasonable buyer relies on, is not actionable. Under Lexmark, the plaintiff must also show a commercial injury proximately caused by the deception.

### Who has standing to sue under Section 43(a) after Lexmark?

The Supreme Court in Lexmark v. Static Control replaced the circuits' competing standing tests with a two-part statutory inquiry: the plaintiff's interests must fall within the zone of interests the Lanham Act protects, meaning a commercial interest in reputation or sales, and the injury must be proximately caused by the misrepresentation, typically because consumers were deceived and withheld business from the plaintiff. Direct competition is not required: a supplier whose products were disparaged qualified in Lexmark itself. Consumers, however, do not qualify: a buyer misled into a bad purchase has no 43(a) claim because that injury is not a commercial interest in reputation or sales.

### What remedies are available for a Section 43(a) violation?

Section 34 provides injunctions, the primary remedy in most cases, and Section 35(a) makes a prevailing plaintiff eligible, subject to the principles of equity, to recover the defendant's profits, the plaintiff's actual damages, and costs, with attorney fees available in exceptional cases. Courts may adjust profit awards and treble damages as compensation, not as a penalty. After Romag Fasteners v. Fossil, willfulness is not an absolute precondition to a profits award for a 43(a) violation, but the defendant's mental state remains a highly important equitable factor, so innocent infringers still have strong arguments against disgorgement while willful ones face it routinely.