["Addiction, EarlyView. ", "\nAbstract\n\nBackground and aims\nNicotine pouches have risen in appeal and use among United States (U.S.) youth and young adults. However, less is known about the initiation determinants of pouch use, and how they compare with those of e‐cigarettes or cigarettes. This study compared the demographic, behavioral, and exposure profiles of adolescents and young adults (AYAs) who initiated nicotine pouch‐use with those who initiated nicotine vaping and those who initiated smoking in a nationally representative U.S. cohort.\n\n\nDesign and settings\nWe used a longitudinal study design. The study setting was the United States (US) with data from the Population Assessment of Tobacco and Health (PATH) Study (Waves 7 and 7.5, 2022–2023).\n\n\nParticipants\nAYAs aged 12–22 (n = 14 326).\n\n\nMeasurements\nThe primary outcomes at follow‐up were initiation of nicotine pouches (never use [2022] to ever use [2023]), vaping, and cigarette smoking. Study predictors at baseline (2022) included demographics, substance and tobacco use, mental health, and social and behavioral exposures. As a secondary objective, susceptibility to vape or smoke at baseline was examined as a predictor of pouch initiation. Separate multi‐variable logistic regression models assessed factors associated with the initiation of each product.\n\n\nFindings\nThe study population comprised 50.6% males, and 45.4% were between the ages 18–22 years, 15–17 years (21.2%), and 12–14 years (33.4%). In 2023, initiation rates were 2.4% for pouch use, 6.2% for vaping, and 3.2% for smoking. Current smoking at baseline was associated with initiating pouch use (adjusted odds ratio [AOR] = 2.8, 95% confidence interval [95% CI]: 1.7–4.4) and initiating vaping (AOR = 5.3, 95% CI: 2.0–13.7) at follow‐up. Current vaping was associated with higher odds of pouch initiation (AOR = 7.9, 95% CI: 5.1–12.4), but current pouch use was not associated with vaping initiation (AOR = 2.4, 95% CI: 0.3–16.2) at follow‐up. Having important peers who use pouches (vs. none) was associated with pouch initiation (AOR = 2.2, 95% CI: 1.2–4.3), similarly for vaping but not for smoking at follow‐up. Among pouch initiators (n = 335), most vaped nicotine at follow‐up (37.9%), 19.7% vaped nicotine and smoked, and 5.2% smoked cigarettes and did not vape.\n\n\nConclusions\nCigarette smoking appears to be associated with both nicotine pouch initiation and vaping initiation among United States adolescents and young adults. Current vaping appears to be associated with pouch initiation, but current pouch use does not appear to be associated with vaping initiation. Important peers using pouches appear to be associated with pouch initiation and vaping initiation but not cigarette smoking. Most pouch initiators in this study concurrently vaped at one‐year follow‐up.\n\n"]