The development of social networks has contributed to the spread of word of mouth on the Internet and provided an opportunity for consumers to get involved in marketing processes. On the other hand, it paved the way for the development of a new form of marketing – influencer marketing. Due to already existing base of followers and the ability to influence them, companies work with influencers to reach their target market more easily. The fundamental goal of this paper was to determine the impact of influencers on consumers when purchasing cosmetic products, and aspects that affect consumer perception of the credibility of influencer. A survey conducted by a survey questionnaire on a sample of 113 respondents found that influencers have an impact on consumer's decision-making process. They have the greatest impact on consumers when searching for information, while the least impact is recorded in their consideration of options. In both cases, the impact is related to the respondent's level of trust in influencers. The influence on the respondents' product cognition need after seeing it on the influencer's profile is greatest among the respondents who are most active on Instagram. Finally, although not significantly pronounced, the influence of influencers on purchases was also noted. Also, the survey found that consumers would rather share dissatisfaction than satisfaction with a product they bought based on an influencer’s recommendation. Ultimately, in order for influencers to gain consumer confidence, it is important that they use the product and that they are experts in the field of the product they are promoting. In addition, most respondents consider influencers less credible if they are paid for the products they promote.