With the aid of social media, influencer marketing has grown to become one of the best tools available today for reaching out to new audiences. There has been a rising question whether influencer marketing could be trusted or not. The stakeholder of the marketing manager must extinguish which influencers could reach new consumers for their branding. Therefore, the number of social media followers that plays its roles as stakeholder assumes the more the followers the highest potential customer, they will gain. Due to that notion, many people want to grab that opportunity by obtaining fake followers on social media platforms. This fraudulent action might harm the influencer marketing and customers due to trustworthy issues. Due to that, the study's goal is to investigate the social influences on young adults' purchasing. The questionnaire is used as a tool for gathering data. The objectives of this study is to examine the factors, such as source legitimacy, source attractiveness, and fit between social influencer and product endorsement, that affect young adults' purchasing decisions in Malaysia. To gather primary data, a sample of 388 respondents among the young adult were distributed survey questionnaires. In observing the independent variables of the study (source credibility, source of attractiveness and the fit between social influencer and product endorsement) Pearson Correlation Coefficient and Multiple Linear Regression Analysis is conducted. All of the variables have a substantial impact on the purchasing behaviour of young adults. The study concludes with a discussion of the summary findings, research implications, limitations, and recommendations for further research.