Can food really boost serotonin? Here's what the science says

You might have heard serotonin referred to as the 'happy hormone' – but it does far more for us than support our mood.

Serotonin is a chemical messenger (or neurotransmitter, to use its proper name) found in the gut, brain and other parts of the body.

It plays a role in our, external:

"Serotonin has a protective effect to give us resilience and reduce stress," explains David Nutt, professor of neuropsychopharmacology at Imperial College London.

But – and it's a big but – it's hard to measure what levels of serotonin are linked to positive mental health, he says.

Some antidepressants , externalcan boost low serotonin, says Nutt. But taking that route is something you'd need to discuss with your GP.

The idea that food can help with depression and stress comes down to an essential amino acid: tryptophan.

"Once digested, tryptophan is transported through the blood into the brain where it gets converted to serotonin," explains Nutt.

Tryptophan (or l-tryptophan) is a building block of protein and only small amounts are necessary to stay healthy.

The body can't make it on its own, so we need to get it through our diet.

Happily, you can find it in plenty of everyday foods, external, including:

Some studies, external have shown people experiencing depression have low tryptophan levels and might experience more panic and anxiety than those with normal levels.

And while not all the tryptophan we eat reaches the brain, some people have reported, external fewer symptoms of depression and better mood after increasing their intake of tryptophan-rich foods.

Sadly though, it's not a cure-all. Tryptophan alone can't lift depression, Nutt stresses.

"But it can help prevent it, especially in people with a vulnerability to depression."

Consultant psychiatrist Dr Nick Walsh agrees, explaining that it needs the help of other nutrients, vitamins and minerals.

He's on board with eating tryptophan-rich foods in their whole, unprocessed form, combined with cutting back on refined sugar and looking after gut health.

"To increase your serotonin levels by making some changes that are consistent with a healthy, balanced diet is a good thing to do," he says.

If only it were that easy.

Not all experts agree that low levels of serotonin directly cause depression. In fact, UCL scientists say there's no clear evidence, external that serotonin levels or serotonin activity are responsible for depression.

As for upping our intake of tryptophan-rich foods to boost mental health? Some argue there's no robust evidence of that either.

Prof Allan Young, director of the Centre for Affective Disorders at King's College London, says tryptophan can work as an anti-depressant for some people, but there's no research of its impact when it comes from food.

"Studies have involved supplements at much higher doses than you would get from any dietary intake," he says.

Prof Felice Jacka, director of the Food and Mood Centre at Melbourne's Deakin University, adds another twist.

Tryptophan needs to be transported from the bloodstream to the brain by certain amino acids, she says.

But it has to compete for this transport with other proteins in the food we eat, which restricts the amount that gets through.

"Even a tiny amount of protein in foods is enough to prevent an increase in tryptophan," she says.

But eating carbohydrates alongside tryptophan-rich foods can boost the amount of tryptophan absorbed by the brain, external.

It could be that high-carbohydrate foods themselves increase serotonin in the brain, she says. This is because carbohydrates release insulin – and excessive insulin curbs the competition for transport, external, allowing more tryptophan to hitch a lift to the brain.

So what should you do?

The science of serotonin is still evolving.

But one thing we can do is focus on what we know works, says Walsh.

"What is important is eating a balanced diet that supports the gut microbiome and [getting] a full range of nutrients."

If you or someone you know is concerned about your mental health, help and support is available.

Originally published October 2024. Updated March 2026.

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