KOL (Key Opinion Leader)

A KOL (key opinion leader) is a person whose word carries weight in a specific field, so many people follow their praise or criticism of a product. In marketing, a KOL is someone a brand pays, or sends free products to, so they introduce that product to their audience.

What is a KOL?

The Cambridge dictionary defines an opinion leader as a person whose opinions about a product or issue have a big influence on the opinions of others (Cambridge Business English Dictionary, accessed October 2026). The word “key” is about scope: a dermatologist can be a KOL for sunscreen but not for phones.

An influencer, per Cambridge, is someone active on social media who can shape people’s opinions or persuade them to buy a product (Cambridge Dictionary, accessed October 2026). A KOL does not have to be active online. An influencer is tied to social media by definition.

KOL vs KOC vs influencer

The lines blur. One person can be a beauty KOL and also sell through affiliate links. See also KOC (key opinion consumer).

KOL rules in Vietnam

Law No. 75/2025/QH15, which amends Vietnam’s Advertising Law and took effect January 1, 2026, calls anyone who directly advertises, recommends or endorses a product online an “advertising product conveyor.” Article 15a requires them to follow consumer protection law, pay tax on advertising income and take legal responsibility if the content is false. Influencers carry two extra duties: check the advertiser and the product documents, and not promote anything they have not used or do not fully understand; and announce that the content is advertising right before and during the promotion (Official Gazette, Law No. 75/2025/QH15, June 2025).

Decree 55/2024/ND-CP defines an influencer as an expert, a respected person or someone with public attention who is sponsored in any form by a business to promote products, including people with a significant following online. According to Vietnam’s Ministry of Industry and Trade, failing to disclose sponsorship in advance can bring a fine of VND 20 to 30 million (Ministry of Industry and Trade, accessed October 2026).

Decree 342/2025/ND-CP, which guides the Advertising Law from February 15, 2026, gives advertisers the right to prioritize creators who have been trained on advertising law by the Ministry of Culture, Sports and Tourism (Decree 342/2025/ND-CP, Article 19, December 2025).

Ad disclosure on TikTok and Meta

TikTok requires creators to turn on the commercial content disclosure setting for any post that promotes a brand or product. A video flagged as undisclosed commercial content triggers a notification; if the creator does not turn on the label or appeal within 24 hours, the video loses eligibility for the For You feed (TikTok, Commercial Content Disclosure, April 2026).

On Facebook, Instagram and Threads, branded content uses a “Paid partnership with” label naming the brand. Posts with affiliate links need the label too (Meta Business Help Center, accessed October 2026).

What one KOL post costs (hypothetical)

A cosmetics brand pays a KOL VND 60 million for one video. The video gets 400,000 views, and the KOL’s discount code records 300 orders.

• CPM: 60,000,000 / 400,000 x 1,000 = VND 150,000.
• Cost per order: 60,000,000 / 300 = VND 200,000.

If each order makes VND 150,000 in gross profit, the sales side has not broken even. The post can still be worth it if the goal was awareness, so agree on the KPI before signing the contract.

Frequently asked questions

How many followers does a KOL need?

There is no set threshold. Decree 55/2024 gives no number and only refers to a “significant” following.

If a KOL only gets free product, does the post still need an ad label?

It should have one. Decree 55/2024 counts sponsorship “in any form,” which covers free product.

If you need a KOL brief tied to TikTok or Meta ads, see Adtek’s Creative Strategy page.