Citric Acid 100g
Citric acid is keto friendly - zero carb, zero fat, zero protein and containing 104kJ energy per gram.
With citric acid you can rest assured it's not going to mess with your blood glucose levels and it doesn't spike insulin either. Such a tiny amount is used across a whole batch of food so in practice is really unlikely that you'd consume anywhere near enough to dramatically affect your ketone production. Ultimately with anything keto, diet, way of living related, individual experiences do vary.
Macros: zero carb, zero fat, zero protein and containing 104kJ energy per gram.