Summary:
ADHD is one of the most common neurodevelopmental conditions, typically diagnosed before age seven. It is characterised by inattention, hyperactivity, and impulsivity, and can interfere with school performance, family life, and peer relationships. Risk factors may include genetics, prenatal exposure to tobacco or alcohol, and environmental influences. Management of ADHD often involves a combination of behavioural therapy, lifestyle changes, and medication. Stimulants such as methylphenidate are commonly prescribed, and non-stimulants are used when stimulants are not suitable. Lifestyle changes, including sleep, exercise, and diet, can also support symptom management. Recently, interest has grown in the use of supplements that may help manage ADHD symptoms through various mechanisms, such as improving neurotransmitter function or enhancing cognition. This systematic review evaluated the effects of four commonly used supplements: L-theanine, caffeine, Ginkgo biloba, and Bacopa monnieri. Results showed that L-theanine improved sleep efficiency in some cases. Caffeine alone showed minimal benefit, though its combination with L-theanine may help attention. Bacopa monnieri consistently improved attention, hyperactivity, and memory. Ginkgo biloba also reduced ADHD symptoms, especially inattention, though it was less effective than standard medication. In summary, these supplements may offer mild benefits as complementary treatments for ADHD. Further research is needed to confirm safe dosages and evaluate long-term use.
Abstract:
Objective: This review aims to assess the efficacy and safety of different supplements, such as L-theanine, caffeine, Ginkgo biloba L., and Bacopa monnieri for improving ADHD symptoms, to determine the most effective supplement and provide insight for medical practice. Methods: International databases (PubMed/MEDLINE and Scopus) were searched for English-language RCTs, open-label studies, and cross-sectional studies. Results: Studies on L-theanine, caffeine, Ginkgo biloba L., and Bacopa monnieri have shown various effects on ADHD symptoms. L-theanine improved sleep efficiency but not other sleep parameters. Caffeine showed no significant benefits, although its combination with L-theanine may enhance attention. Bacopa monnieri consistently improved inattention, hyperactivity, and memory, whereas Ginkgo biloba L. reduced ADHD symptoms, particularly inattention, but was less effective than methylphenidate. Conclusions: The evidence revealed the potential use of supplements as complementary ADHD treatments under clinical guidance. The limited effect of supplements cannot replace the well-documented efficacy of stimulants for ADHD treatment. Additional studies are needed to ascertain the most effective dosages and the safety of these supplements as adjunctive treatments for ADHD.
Article Publication Date: 28/04/2025
DOI: 10.3390/nu17091482
