Health Benefits of Borage: What the Evidence Actually Shows

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Borage is really two things at once, and keeping them apart is the key to understanding it. As a food, it’s a soft, faintly cucumber-scented Mediterranean leafy green — the borrajas prized in Spanish and Ligurian kitchens — eaten cooked, low in calories, and genuinely rich in vitamin C, potassium, and iron. As a supplement, it’s borage seed oil (you’ll also see it sold as starflower oil), one of the richest plant sources of an omega-6 fatty acid called gamma-linolenic acid, or GLA.

Here’s the honest version of the health benefits of borage. The best-supported one is fairly narrow: the GLA in the seed oil offers modest relief of rheumatoid arthritis symptoms. Most of the older folk claims — that borage purifies the blood, breaks fevers, clears the chest, or heals eczema — are either traditional uses without strong proof or, in a couple of cases, claims that regulators have specifically looked at and rejected. And borage comes with a real safety catch that its cheerful reputation tends to skip: the leaves and flowers contain natural compounds that can harm the liver. With borage, how you use it matters as much as whether you use it.

This is the practical version — what borage does, what it doesn’t, and how to enjoy it without taking on risk you didn’t sign up for.

Borage at a glance: the vegetable and the oil

Borage (Borago officinalis) is an annual herb in the Boraginaceae family, native to the Mediterranean and now grown — and found growing wild — across Europe and the Americas. The whole plant is covered in fine bristly hairs, which is why cooks blanch or cook the leaves and stalks rather than eat mature leaves raw. Its star-shaped blue flowers are edible too.

Two parts of the plant get used in completely different ways, and almost all the confusion about borage comes from mixing them up:

• The leaves, stalks, and flowers are used as a vegetable and in traditional herbal preparations. This is the culinary borage that shows up in Mediterranean cooking and in older herbals describing borage’s traditional flower and leaf uses.
• The seeds are pressed for borage seed oil, which is standardized for GLA and sold in capsules. Borage seed oil is roughly 25% GLA — more than double the GLA in evening primrose oil, at about 10% [Memorial Sloan Kettering Cancer Center, 2022].

When a study reports a health effect, it’s almost always testing the oil, not the plate of cooked greens. That distinction runs through everything below.

Borage nutrition facts

As a vegetable, borage earns its place on the plate. It’s mostly water, very low in calories, and unusually mineral-dense for a leafy green. Here’s what 100 grams of raw borage leaves provides, using US Department of Agriculture reference data [USDA FoodData Central, 2019].

Nutrient	Per 100 g	Notes
Calories	21 kcal	Very low calorie density
Water	~93 g	Most of the leaf by weight
Protein	1.8 g	Modest
Carbohydrate	~3 g	Little sugar
Vitamin C	35 mg	~39% of the Daily Value
Vitamin A	210 µg RAE	~23% of the Daily Value
Potassium	470 mg	~10% of the Daily Value
Iron	3.3 mg	~18% of the Daily Value — high for a leafy green
Calcium	93 mg	Useful contribution
Magnesium	52 mg	~12% of the Daily Value

The standouts are vitamin C, vitamin A, and iron, along with a potassium-rich, low-sodium profile typical of leafy greens. Borage also contains mucilage — a soft, gel-like plant fiber that gives the cooked leaves their silky texture and underlies borage’s traditional use as a soothing, cough-loosening food [Memorial Sloan Kettering Cancer Center, 2022]. As a fresh vegetable eaten in normal amounts, that’s a genuinely good nutritional package. The cautions in this article are about concentrated forms — teas, juices, and supplements — not an occasional serving of the cooked greens.

The health benefits of borage, graded by the evidence

Not every claim about borage is on equal footing. Here’s where the science is reasonably solid, where it’s only traditional, and where it has actually been tested and come up short.

Rheumatoid arthritis: the strongest case (borage seed oil)

Evidence: moderate — the best-supported use. This is the one benefit with real human-trial support, and it’s about the oil, not the vegetable. A Cochrane systematic review of herbal treatments for rheumatoid arthritis concluded that oils containing GLA — including borage seed oil, evening primrose oil, and blackcurrant seed oil — probably reduce pain and may improve function, without a clear increase in side effects [Cochrane review of herbal therapy for rheumatoid arthritis, 2011]. Memorial Sloan Kettering’s cancer-center herb database reaches a similar, measured conclusion: borage may help relieve rheumatoid arthritis symptoms, while noting that the right dose and treatment length still aren’t well defined [Memorial Sloan Kettering Cancer Center, 2022].

The proposed mechanism is reasonable: GLA is converted in the body to dihomo-gamma-linolenic acid, which nudges the body toward less-inflammatory signaling molecules [Kapoor & Huang, 2006]. Two honest caveats belong with this. “Moderate benefit” means a helpful add-on for symptoms, not a replacement for the disease-modifying drugs that actually protect joints — so this is a conversation to have with your rheumatologist, not a reason to change your treatment on your own. If you’re exploring GLA sources, blackcurrant seed oil is another.

Coughs and congestion: a traditional expectorant

Evidence: traditional, with limited early research. Borage has a long history as a soothing remedy for coughs and chest congestion, and there’s a plausible reason: its mucilage acts as a demulcent, coating irritated tissue, and it has been used traditionally as an expectorant to help loosen phlegm [Memorial Sloan Kettering Cancer Center, 2022]. Laboratory and animal work on borage leaf extract has shown relaxant effects on airway and gut muscle, which fits the traditional picture [Journal of Ethnopharmacology, 2007]. In one small preliminary trial, a borage extract improved some symptoms of moderate asthma but not the underlying airway inflammation [Memorial Sloan Kettering Cancer Center, 2022].

The takeaway: as a warm, soothing food when you have a cold, borage is a reasonable comfort. It is not a treatment for asthma, bronchitis, or any respiratory infection, and it shouldn’t delay care for one.

A mild diuretic and “blood purifier”: mostly tradition

Evidence: traditional. Borage has been used for centuries to promote sweating and urination and, in old herbal language, to “purify the blood” — hence its folk use for fevers, gout, and joint complaints. A mild diuretic effect has been attributed to its malic acid content [Memorial Sloan Kettering Cancer Center, 2022], and the sweat-promoting reputation is old enough to be baked into the plant’s name. But “blood purifier” (depurative) is a traditional concept, not a measured medical effect, and there’s no good clinical evidence that borage treats gout, arthritis by this route, or kidney conditions. Enjoy it as a food if you like it; don’t rely on it to manage any of those conditions.

Skin, PMS, and menopause: where claims outrun evidence

Evidence: weak to negative. Borage oil is widely marketed for eczema, premenstrual syndrome, menopausal symptoms, and skin smoothing, largely on the strength of its GLA. When those claims have actually been tested, they haven’t held up well. Controlled trials do not support borage oil for atopic eczema — improvements have generally matched placebo [Memorial Sloan Kettering Cancer Center, 2022]. And the European Food Safety Authority, after reviewing the evidence, declined to approve GLA health claims for cholesterol, blood pressure, menstrual discomfort, skin, or cognitive function, finding the evidence insufficient [EFSA GLA health-claims opinion, 2011]. Borage oil may still turn up in cosmetics as an emollient, which is a different, lower bar than a medical claim.

The safety catch: borage and your liver

Pyrrolizidine alkaloids, explained

Borage plants naturally contain pyrrolizidine alkaloids (PAs) — a group of compounds that can be toxic to the liver and are considered possibly carcinogenic. They’re found in the leaves and flowers, including compounds such as amabiline, lycopsamine, and intermedine [Memorial Sloan Kettering Cancer Center, 2022; NIH LactMed]. In the body, certain PAs are converted by the liver into reactive by-products that can injure liver cells; the risk rises with the amount taken and, especially, with how long you take it.

For most people, an occasional serving of well-cooked borage as a vegetable is not the concern. The concern is concentrated and repeated exposure — daily borage-leaf tea, fresh borage juice taken as a “spring tonic,” or leaf-based supplements — where PA intake can climb. European food-safety authorities and the UK’s food regulator have flagged borage-leaf teas as a potential source of unsafe PA levels, which is why the traditional advice to “drink a glass of fresh borage juice every morning” is exactly the habit to avoid. If you have any liver condition, skip borage leaf and flower preparations altogether, and see our guide to supporting liver health through diet.

There’s also a foraging hazard worth naming: outside of its flowering season, borage can be mistaken for toxic plants. A documented near-fatal poisoning occurred when someone confused borage with foxglove, which is dangerously cardiotoxic [Memorial Sloan Kettering Cancer Center, 2022]. If you’re not completely certain of an identification, don’t eat it.

Why borage seed oil is treated differently

The pyrrolizidine alkaloids sit in the plant, not in the fatty seed oil — so properly produced borage oil should contain little to none. The catch is that “should” depends on the manufacturer. Reputable guidance is specific: only use borage oil certified free of unsaturated pyrrolizidine alkaloids, and even then, chronic use is discouraged, particularly for anyone with liver disease [Memorial Sloan Kettering Cancer Center, 2022; NIH LactMed]. Because supplements aren’t reviewed for safety and effectiveness by the FDA before they’re sold, PA-free certification and third-party testing are the reader’s main protection here.

Side effects and who should avoid borage

Borage oil is generally well tolerated in adults at typical doses, but it isn’t side-effect-free. Reported effects include headache, abdominal pain, nausea, belching, and loose stools [Memorial Sloan Kettering Cancer Center, 2022]. Two rarer but serious signals are worth knowing: a case of prolonged seizure activity was linked to about a week of borage oil use in a previously healthy adult, so people with epilepsy or a seizure history should be especially cautious; and prolonged use has been associated with liver injury [Memorial Sloan Kettering Cancer Center, 2022].

Talk to your doctor before using borage, and avoid it, if you:

• have any liver disease or take medications that can stress the liver;
• have a seizure disorder;
• are pregnant or breastfeeding (see below);
• take blood thinners or regular NSAIDs (see below);
• have surgery scheduled (stop well beforehand because of the bleeding-risk concern).

Drug interactions worth knowing

• Blood thinners and antiplatelet drugs (e.g., warfarin, aspirin): GLA-rich oils can lengthen bleeding time, so combining borage oil with anticoagulant or antiplatelet drugs may raise bleeding risk. Because borage oil is about 25% GLA, this caution is taken seriously [Memorial Sloan Kettering Cancer Center, 2022].
• Liver-toxic medications (e.g., certain antifungals, anabolic steroids): borage’s pyrrolizidine alkaloids add to the liver burden, so the combination is best avoided [Memorial Sloan Kettering Cancer Center, 2022].
• NSAIDs (aspirin, ibuprofen, COX-2 inhibitors): in theory, regular NSAID use may blunt borage oil’s effects [Memorial Sloan Kettering Cancer Center, 2022].

This isn’t a complete list. Because herbs can change how prescription drugs behave, tell your doctor or pharmacist about any supplement you’re taking.

Pregnancy, breastfeeding, and infants

Borage should be avoided during pregnancy and breastfeeding. Its pyrrolizidine alkaloids can pass into breastmilk, and borage oil has been linked to potential harms in pregnancy, including a prostaglandin effect that could theoretically trigger early labor [NIH LactMed; Memorial Sloan Kettering Cancer Center, 2022]. There’s also a specific infant hazard: in Spain, borage purée — which is high in nitrates — has been tied to cases of methemoglobinemia (“blue baby syndrome”) in babies, whose systems can’t handle large nitrate loads [Memorial Sloan Kettering Cancer Center, 2022]. Borage is not an appropriate food or remedy for infants.

How to use borage safely

If you want to enjoy borage, the safe lane is the culinary one, used occasionally rather than daily:

• As a cooked vegetable. Use young, tender leaves and stalks; blanch or cook them (cooking softens the bristly hairs), and enjoy them the way Mediterranean cooks do — for example, paired with potatoes or folded into soups. Treat it as an occasional green, not a daily staple.
• As an edible flower. The blue star-shaped flowers make a pretty, mild garnish in small amounts.
• Skip the concentrated leaf preparations. Daily borage-leaf tea and fresh borage-leaf juice are the exposures most likely to push pyrrolizidine alkaloids to levels regulators warn about.
• If you’re considering borage seed oil, choose a product certified free of unsaturated pyrrolizidine alkaloids, don’t use it long-term without medical guidance, and clear it with your doctor first if you take any regular medication.

When to see a doctor

Borage is not the right tool for a medical problem, and a few situations call for professional care rather than a home remedy. Contact your doctor promptly — or seek urgent care — if you notice:

• Signs of liver trouble: yellowing of the skin or eyes (jaundice), dark urine with pale stools, persistent nausea, or pain in the upper-right abdomen — especially after using borage products.
• A high or persistent fever, a cough lasting more than a few weeks, coughing up blood, or shortness of breath.
• Any seizure activity, which is a medical emergency.
• Unusual bleeding or bruising, particularly if you take a blood thinner.

In the US, you can reach Poison Control at 1-800-222-1222, and you should call 911 for any severe or life-threatening symptoms such as a seizure, trouble breathing, or a suspected poisoning.

HEALTH DISCLAIMER: This article is for general education and information only. It is not medical advice and is not a substitute for diagnosis, treatment, or guidance from a qualified healthcare professional. Do not use it to self-diagnose or to delay seeking care. Borage and borage seed oil can affect the liver, interact with medications, and are not safe for everyone. If you are pregnant, breastfeeding, have a liver condition, a seizure disorder, or another medical concern, or take prescription medication, talk with your doctor or pharmacist before using any borage product. If you think you are having a medical emergency, call 911.

Frequently Asked Questions

References

1. Memorial Sloan Kettering Cancer Center. About Herbs: Borage. Last updated March 31, 2022. → View source
2. Cameron M, Gagnier JJ, Chrubasik S. Herbal therapy for treating rheumatoid arthritis. Cochrane Database Syst Rev. 2011;(2):CD002948. DOI 10.1002/14651858.CD002948.pub2 (PMID 21328257). → View source
3. U.S. Department of Agriculture, Agricultural Research Service. FoodData Central: Borage, raw (FDC ID 170481), SR Legacy. → View source
4. National Institutes of Health. Drugs and Lactation Database (LactMed): Borage. (PMID 30000849). → View source
5. EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on health claims related to gamma-linolenic acid (GLA). EFSA Journal. 2011;9(4):2059. DOI 10.2903/j.efsa.2011.2059. → View source
6. Kapoor R, Huang YS. Gamma linolenic acid: an antiinflammatory omega-6 fatty acid. Curr Pharm Biotechnol. 2006;7(6):531–534. DOI 10.2174/138920106779116874 (PMID 17168669). → View source
7. Gilani AH, Bashir S, Khan AU. Pharmacological basis for the use of Borago officinalis in gastrointestinal, respiratory and cardiovascular disorders. J Ethnopharmacol. 2007;114(3):393–399. → View source