Caffeine Intake Recommendations for Adolescents Aged 12-18
The specific claim that adolescents aged 12-18 should limit caffeine to "at most 100 mg/day" is not directly supported by the available guideline evidence; instead, the most recent guidelines recommend limiting caffeine to <2.5 mg per kg of body weight daily for children and adolescents, which translates to approximately 125-175 mg/day for most adolescents in this age range. 1
Evidence-Based Caffeine Limits for Adolescents
The 2025 guidelines recommend that children and adolescents should limit caffeine to <2.5 mg per kg of body weight daily, which is equivalent to approximately 1-2 cups of tea or 1 small cup of coffee daily 1. This weight-based approach is more precise than a fixed 100 mg limit.
Practical Translation of Weight-Based Guidelines
- For a 50 kg (110 lb) adolescent: maximum ~125 mg/day
- For a 70 kg (154 lb) adolescent: maximum ~175 mg/day 1
The 2022 Current Obesity Reports guidelines for adolescence (13-18 years) recommend to "limit caffeine" but do not specify an exact numerical threshold, only stating that caffeine should be limited alongside added sugars, saturated fat, and sodium 2.
Evidence Supporting Lower Thresholds
Research evidence suggests that high caffeine intakes exceeding 5 mg/kg/day are associated with increased risk of anxiety and withdrawal symptoms in children and adolescents 1, 3. This would translate to approximately 250-350 mg/day for most adolescents, well above the 100 mg threshold mentioned in your question.
The 100 mg Recommendation Context
The 100 mg/day figure appears in recent research as a recommended maximum for adolescents in the context of school beverage policies 4. A 2025 study in the Journal of the Academy of Nutrition and Dietetics states that "according to recommendations, adolescents should limit caffeine intake to no more than 100 mg/d" 4. However, this appears to be a more conservative interpretation rather than the primary guideline recommendation.
International Guideline Variations
- Health Canada: recommends 2.5 mg/kg body weight/day for children and adolescents 5
- European Food Safety Authority (EFSA): recommends 3 mg/kg body weight/day for children and adolescents 5
- Both agencies recommend 400 mg/day for adults 5
Clinical Implications
The safest approach is to use the weight-based recommendation of <2.5 mg/kg/day rather than a fixed 100 mg limit, as this accounts for the significant variation in body size among 12-18 year-olds 1. For practical counseling, advising adolescents to limit intake to 1-2 cups of tea or 1 small cup of coffee daily provides a tangible guideline 1.
Common Caffeine Sources to Monitor
- Coffee: 50-300 mg per 8 oz serving 1
- Energy drinks: 95 ± 14 mg average 4
- Soda: variable content, historically the primary source 6
- Tea: 15-50 mg per 8 oz serving 1
Important Caveats
Approximately 10-25% of caffeine-consuming adolescents aged 12-19 years exceed even the more liberal Canadian guidelines 6, indicating that overconsumption is common in real-world settings. The trend toward increased energy drink and coffee consumption among adolescents (with declining soda intake) means that monitoring specific beverage choices is increasingly important 6.