This is a randomised, double-blind, placebo-controlled, parallel-group, multi-centre study of tricaprilin as AC-SD-03 compared with placebo for the reduction of migraine in participants with frequent migraine.

Inclusion Criteria:

1. Participant must be 18 to 70 years of age inclusive, at the time of signing the informed consent.
2. Participants who have frequent (episodic or chronic) migraine with or without aura, for at least 1 year, according to the International Classification of Headache Disorders version 3 beta (ICHD 3-beta), age at time of onset must be <50 years.
3. Participants must have a certain number of migraine headaches days per month, as confirmed by the baseline measurement period.
4. Use of one allowed migraine prophylactic is permitted if the participant has been on a stable dose for at least 2 months prior to the screening.
5. Participants must have failed (no therapeutic response) 1-4 migraine prophylactic treatments.
6. The participant is able to tolerate a 12.5g dose of AC-SD-03 (containing 5g of tricaprilin) as per sentinel dose challenge at the Baseline Visit.
7. From Visit 2 to Visit 3 (baseline measurement period), the participant has sufficient compliance (at least 80%) with daily eDiary headache entries.

Exclusion Criteria:

1. In the opinion of the Investigator, has presence or history of an advanced, severe, progressive, or unstable disease of any type that could interfere with efficacy and safety assessments, or put the participant at risk.
2. Use of barbiturates (and/or butalbital-containing analgesics) or opioids (and/or opioid-containing analgesics) for migraine acute treatment ≥ 4 days per month on average and/or in the last month prior to Screening Visit.
3. Use in the last 3 months prior to Screening Visit of CGRP agents, Botox injections, TENS, cranial nerve blocks, trigger-point injections, acupuncture, CBD-containing products, infusion therapy.
4. Current use, or use within 3 months of Visit 2 (baseline), of Axona® or other MCT-containing products (such as coconut oil). Use of MCT-containing products is not allowed at any time during trial participation.
5. Current use, or use within 3 months prior to Screening, of a ketogenic diet, low-carb diet, intermittent fasting (including the 5:2 diet). Ketogenic diets, low-carb diet, intermittent fasting (including the 5:2 diet) are not allowed during the study.