Blackcurrant
Quick Facts
- What it is: A sour, dark purple Nordic berry, rich in vitamin C, eaten as food and sold as extract or seed oil.
- Main uses: Vitamin C intake, Eye strain from screen work, Exercise recovery, Comfort during colds
- Best for: People wanting a food source of vitamin C, People who enjoy it as food and are curious about mild extra benefits
- Active ingredients: Vitamin C, Anthocyanins, Flavonols and tannins, Gamma-linolenic acid (in seed oil)
- Forms: Fresh or frozen berries, Juice and cordial, Jam and syrup, Berry extract capsules, Seed oil capsules, Dried leaf tea
- Time to effect: Days to a few weeks, and it may do nothing.
- Side effects: Mild: loose stools, stomach upset, tooth acid wear; allergy is rare.
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What is Blackcurrant?
Blackcurrant is the small, dark purple berry of the shrub Ribes nigrum. It is an everyday food across northern Europe.
Its name changes from country to country. In Norway and Denmark it is solbær, and in Sweden svarta vinbär. In Finland it is mustaherukka, and in Iceland sólber.
The berry is very sour and very rich in vitamin C. It is eaten as juice, cordial, jam and dried powder. The seeds are pressed for oil, and the leaves have been brewed as a tea.
People use blackcurrant today for vitamin C, for tired eyes, for sport recovery and for winter colds. As a food, its vitamin C content is well established. As a remedy, the human evidence is thin and comes from small, short studies.
Long use in Scandinavian kitchens and folk practice is not proof that blackcurrant works. It is also not proof that a concentrated supplement is safe. Those are separate questions, and this page keeps them apart.
If you take antiplatelet drugs (medicines that stop blood cells clumping together), read the safety section below.
How does Blackcurrant work?
The clearest thing blackcurrant does is supply vitamin C. Vitamin C is needed to build collagen, the protein that holds skin, gums and blood vessels together. It prevents and treats scurvy, a disease caused by too little vitamin C.
The dark colour comes from anthocyanins (the purple plant pigments). In test tubes, these mop up free radicals, which are unstable molecules that can damage cells. Whether that same effect matters inside the body is not settled.
Small human trials have looked at blackcurrant anthocyanins and blood flow. Some found slightly better blood flow and fuel use during exercise. The trials were short, small and not all positive.
For eyes, the idea is that anthocyanins reach the retina and ease the strain of close screen work. A few small Japanese trials point that way. This is an early hint, not a settled finding.
Blackcurrant seed oil contains gamma-linolenic acid (GLA), a fatty acid. In lab and animal work, GLA shifts how the body makes signals linked to swelling. Human results for joint and skin problems have been mixed and weak.
The leaves contain tannins and flavonoids. They were used as a folk tea for aching joints. There is almost no human trial evidence for the leaf.
What forms does Blackcurrant come in?
Blackcurrant turns up far more often as food than as medicine.
- Fresh or frozen berries.
- Juice, cordial and squash, often sweetened.
- Jam, jelly, syrup and sauce.
- Dried berries and freeze-dried powder.
- Capsules of anthocyanin-rich berry extract.
- Blackcurrant seed oil capsules.
- Dried leaf tea.
- Lozenges and winter drinks, often with added vitamin C.
Extract capsules are far more concentrated than juice. Seed oil is a different product again, with no vitamin C to speak of.
Check which one a product actually contains before you judge it.
Where it comes from:
Blackcurrant has a long place in Nordic and wider European home use. Scandinavian households made solbærtoddy, a hot blackcurrant drink taken in winter and during colds. The sharp taste and good keeping quality made it a staple of jams and cordials.
In folk practice the leaf tea was drunk for aching joints. It was also taken as a mild diuretic, meaning something that makes you pass more urine. Russian and central European herbal writing recorded similar uses.
None of these old uses was tested the way we would test a medicine now.
During the Second World War, British children were given blackcurrant syrup, because citrus could not be shipped. That use rested on vitamin C, which was by then well understood. It is the clearest historical case where the benefit was real and explainable.
Who should avoid Blackcurrant?
- Do not use blackcurrant in any form if you have had an allergic reaction to it or to related currants or gooseberries.
- Do not add blackcurrant seed oil or high-dose extract capsules if you take warfarin, apixaban, rivaroxaban, aspirin or clopidogrel, unless your doctor agrees.
- Do not take concentrated extract or seed oil in the two weeks before planned surgery, because of a possible small bleeding risk.
- Avoid concentrated blackcurrant capsules and leaf tea if you are pregnant or breastfeeding, as they have not been tested; the berry as food is fine.
- Avoid large amounts of sweetened blackcurrant cordial or jam if you have diabetes (high blood sugar).
- Do not use blackcurrant leaf tea as a diuretic (a product that increases urine) if you have kidney disease or heart failure, without medical advice.
- Do not rely on blackcurrant instead of seeing a doctor for an eye problem, a joint disease or an infection.
When should you see a doctor?
See a doctor straight away if you get swelling of the lips, tongue or face, a spreading rash, or trouble breathing after taking it.
Stop concentrated capsules and get advice if you notice unusual bruising, bleeding gums or nosebleeds, especially on a blood thinner.
Book an appointment if eye strain, blurred vision or joint pain keeps getting worse. Those need a proper diagnosis, not a berry.
Is Blackcurrant legal where you live?
In the UK, the EU, the US, Canada and Australia, blackcurrant is an ordinary food. Capsules and oils are sold as food supplements or dietary supplements, not as licensed medicines. Growing the plant was once restricted in parts of the United States because it can spread a pine tree disease, and a few states still limit which varieties may be planted.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
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