Aspartame and migraine

What the studies show

Study	Design	People	Aspartame	Result
Lipton 1989	Survey at a headache unit	171 patients	Not given	8.2% named aspartame as a trigger, three times as often in migraine as in other headache types
Schiffman 1987	Double-blind crossover	40 who reported repeated headaches after aspartame	30 mg per kg challenge	Headache in 35% after aspartame, 45% after placebo. No significant difference
Van den Eeden 1994	Double-blind randomised crossover, four 7-day periods	32 with self-identified aspartame headache	30 mg per kg per day	Headache on 33% of days on aspartame, 24% on placebo. Significant

The doses are study doses, not a safe or unsafe level.

Martin and Vij counted two positive and two negative provocation studies and called the evidence conflicting (Martin 2016). The Migraine Trust says there is not enough evidence that aspartame is likely to be a trigger for most people. No mechanism is established. Schiffman found no aspartame-related changes in vital signs or in the blood hormones measured.

Why the results disagree

• Who took part. Both crossover trials enrolled people who suspected aspartame, not a general migraine group. In Van den Eeden, headaches were particularly frequent among those who were very sure aspartame had caused them before.
• Length of exposure. Schiffman gave a single challenge. Van den Eeden repeated the exposure over several days.
• Dropout. About a quarter of Van den Eeden’s participants withdrew, citing frequent or severe headaches or disturbed sleep.
• Size. These are small trials from the 1980s and 1990s. The 2020 systematic review of diet and migraine reported no aspartame results of its own.

How much and how often

In an interview, Vincent Martin, a co-author of the 2016 review, gave his view that aspartame sensitivity may apply to about 2% of people with migraine, that it may need large amounts over a prolonged period, and that headache can appear 24 to 48 hours later (UCHealth). This is a clinician’s estimate, not a trial result.

How to check it in your diary

1. Log products and servings. Aspartame appears in diet drinks and other sweetened products. Check the label, because sweeteners differ.
2. Choose your window before you start. The American Migraine Foundation suggests linking a food to a headache only if it starts within 24 hours. Martin describes up to 48 hours. Write down one rule and keep it.
3. Record caffeine in the same drink. Some diet drinks contain it, and caffeine has its own evidence.
4. Record what the drink replaced. A diet drink instead of a meal is also a skipped meal.
5. Count exposure days with no attack. In the trial above, headache also occurred on a quarter of placebo days.

Talk to a clinician before you restrict your diet. For the general method, see how to test a suspected trigger.