• Saffron performed as well as SSRI antidepressants across eight trials, with fewer side effects reported.
• Roseroot suits low mood that comes with exhaustion after a long period of stress.
• St John’s wort has the deepest evidence of the three for mild to moderate depression.
• St John’s wort also weakens many prescription medicines, including the contraceptive pill and warfarin.
• Low mood often has several drivers at once, so the gut, thyroid and hormones are all worth considering.

A handful of herbal medicines have proper clinical trials behind them for low mood. Three stand out: saffron, roseroot and St John’s wort. I’m a medical herbalist (MNIMH, MCPP), and I was a chemist before I trained in plants. So the research matters to me, and so does what happens when real people take these remedies.

This is the second article in a series on depression. The first looks at the wider foundations, and a companion piece covers diet and mental health. Before the herbs, one thing needs saying.
Antidepressants help many people, and nothing here is a reason to stop a prescribed medicine. Herbal medicine works alongside conventional care. Where it differs is the width of the lens: a herbalist looks at sleep, stress, hormones and digestion as well as mood.

Depression can have several drivers at once, and they shape where support should start.

Your gut is one of them. The gut and brain are in constant conversation through nerves, immune signalling and your gut bacteria. Around 95 per cent of the body’s serotonin is made in the gut, not the brain. I’ve written more about how serotonin connects gut, mood and sleep. 

Hormones matter too. Low mood is common through perimenopause, as oestrogen falls and sleep breaks up. Many women over 40 also meet anxiety for the first time https://nikkihawkes.com/why-am-i-suddenly-so-anxious-in-my-40s/ in these years. An underactive thyroid can look very like depression, and a simple blood test can rule it in or out.

Then there’s the rest of life. Chronic illness, long stretches of pain, an old head injury, and grief can all lie behind a low mood. A herbalist asks a lot of questions before choosing a herb, because the person matters as much as the diagnosis.
If your mood is severely low, or you’ve had thoughts of harming yourself, please seek medical support promptly. Herbal self-help is not the tool for that moment.

Saffron is the world’s most expensive spice. The medicinal part is the stigma, the pollen gathering thread at the centre of the crocus flower. It takes thousands of flowers to produce a usable amount of medicine, which explains the price.

The depression research has grown up around a dose of 30mg a day. A 2025 meta-analysis pooled eight trials that compared saffron head to head with SSRI antidepressants. Across those trials there was no meaningful difference between saffron and the medicines on depression scores. The clearest difference was tolerability, because the saffron groups reported fewer side effects.

Saffron’s price brings a practical caution. Cheap saffron is often padded out with other plant material, so buy it from a supplier you trust. It’s best avoided at medicinal doses in pregnancy, and it needs care if you take medicines that thin the blood. A herbalist who knows your case can advise on both.

Roseroot, also called Rhodiola rosea, is a tonic herb. Herbalists usually choose it for the person whose low mood comes with exhaustion after a long period of stress.

The trial evidence is modest and consistent. In a 12-week trial, adults with mild to moderate depression took roseroot, sertraline or a placebo. Depression scores improved in all three groups. Roseroot’s edge over placebo was small, and the study was too small to be certain of it. Tolerability told a clearer story: 30 per cent of the roseroot group reported side effects, against 63 per cent on sertraline.

An earlier six-week trial tested 340mg and 680mg a day in mild to moderate depression. Both doses improved overall depression measures, and sleep improved alongside them.

A trial hands the same fixed dose to every participant, which is the opposite of herbal practice. Roseroot does its best work when it’s matched to the right person, usually the worn out one. That matching is a herbalist’s job, and it’s part of why trial averages can understate a herb.

St John’s wort, Hypericum perforatum, is probably the most researched herbal medicine there is. For mild to moderate depression the evidence is consistent. A 2023 meta-analysis pooled 14 trials covering 2,270 people. St John’s wort performed at least as well as SSRI antidepressants, with fewer side effects. The picture in severe depression is far less clear, and severe depression needs medical care in any case.

St John’s wort’s main caution is the company it keeps. It speeds up the liver enzymes that clear many prescription medicines, so it can weaken their effect. That list includes the contraceptive pill, warfarin, and some heart, epilepsy, transplant, HIV and cancer medicines. Taken with antidepressants, it can also push serotonin activity too high, which can be serious. So this is not a herb to add on your own alongside prescribed medicines. Medical herbalists are trained to know when herbs can be used safely alongside prescription pharmaceuticals, and this herb is the textbook case for that training.

These three herbs suit different people. Saffron is gentle, comes from a food, and is simple to try. Roseroot fits low mood that’s tangled up with exhaustion and stress. St John’s wort has the deepest evidence, and the most interactions to respect. If anxiety and broken sleep dominate the picture, the calming nervine herbs may be the better place to start.

Or start on your own, with the basics: better meals, sleep that isn’t broken, and a daily walk. They support your mood, and they cost nothing.