["Addiction, EarlyView. ", "\nAbstract\n\nBackground and aims\nUnderstanding key product characteristics of oral nicotine pouches (ONPs), an emerging nicotine product category, is essential to developing evidence‐based regulations that address ONP use among young populations. This experimental trial assessed the effects of variations in nicotine concentration and pH in NPs on two behavioral outcomes of regulatory interest: sensory attributes and appeal.\n\n\nDesign and Intervention\nWe conducted an in‐person, double‐blind, within‐subject randomized experiment involving standardized self‐administration of 4 commercially available NPs (drawn from a pool of 20 ZYN and on! products) varying in nicotine strength (high: 6–8 mg vs. low: 3–4 mg) and pH (high: 8.5–9.3 vs. low: 7.6–8.0). Experimental conditions were not mutually exclusive (i.e., NP with a high pH could either have high or low nicotine concentration, or vice versa), and NPs were randomly assigned without replacement to ensure participants did not receive the same product more than once in each condition.\n\n\nSetting\nLos Angeles metropolitan area in California, United States (U.S.).\n\n\nParticipants\nSeventy‐three young adults (21–35 years, mean[standard deviation] = 23.7[3.1] years; 87.7% males, 49.3% White) who currently use NPs were recruited between October 2024 and July 2025.\n\n\nMeasurements\nParticipant rated ONP appeal and sensory attributes (sweetness, smoothness, bitterness, harshness) on 0 (‘not at all’) to 100 (‘extremely’) scales. Repeated‐measures random‐intercept models assessed the effects of nicotine concentration and pH on the appeal and sensory attributes.\n\n\nFindings\nIn the sample, high (vs. low) nicotine strength produced statistically significant lower ratings of appeal (b = −8.75, 95% confidence interval [CI] = −15.41, −2.08) and smoothness (b = −7.72, 95% CI = ‐14.01, −1.44) and higher harshness ratings (b = 7.21, 95% CI = 1.07, 13.36). No statistically significant linear effects of pH on appeal and sensory attributes were observed. Quadratic analyses revealed non‐linear associations whereby ONP appeal and sweetness declined at both tails of the pH distribution (inverted U‐shape). Statistically significant interactions between nicotine concentration and quadratic pH were observed for appeal and bitterness with stronger quadratic pH effects in high (vs. low) ONPs. In addition, statistically significant pH–sex interactions showed stronger quadratic effects in females (vs. males) for appeal and bitterness.\n\n\nConclusions\nIn this double‐blind randomized experiment among young adult oral nicotine pouch (NP) users in the United States, exposure to NPs with [1] higher vs. lower nicotine concentrations produced lower appeal and smoothness and greater harshness; [2] varying pH produced non‐linear effects, such that appeal and palatability rose at moderate pH levels and then declined at high pH levels, particularly for high‐nicotine NPs and among females.\n\n"]