Short answer: The catechin EGCG is the most researched natural thermogenic compound available, and it is also the ingredient responsible for any mild jitteriness in sensitive users.
Why this ingredient carries a specific, named side-effect note
Rather than a vague "some people react to some ingredients" disclaimer, naming EGCG directly as the source of jitters is a genuinely specific, useful piece of information.
How common this specific reaction actually is
Transient mild jitters from green tea sensitivity are reported in under 1.5% of users — a specific, disclosed frequency worth understanding realistically.
💡 Worth knowing: taking the capsules with food and a full glass of water usually settles this within days.