Cat’s claw is a popular herbal supplement derived from a tropical vine.
It allegedly helps fight a range of ailments, including infections, cancer, arthritis, and Alzheimer’s disease ().
However, only some of these benefits are supported by science.
This article tells you everything you need to know about cat’s claw, including its benefits, side effects, and dosage.
Cat’s claw (Uncaria tomentosa) is a tropical vine which can grow up to 98 feet (30 meters) tall. Its name comes from its hooked thorns, which resemble the claws of a cat.
It is found mainly in the Amazon rainforest and in other tropical areas of South and Central America.
The two most common varieties are Uncaria tomentosa and Uncaria guianensis. The former is the type often used in supplements in the United States ().
The bark and root have been used for centuries in South America as a traditional medicine for many conditions, such as inflammation, cancer, and infections.
Cat’s claw supplements can be taken as a liquid extract, capsule, powder, or tea.
Summary Cat’s claw is a tropical vine used for centuries as a traditional medicine. Today, it’s commonly consumed as a supplement due to its alleged health benefits.
Cat's claw has soared in popularity as a herbal supplement due to its alleged health benefits — though only the claims below are backed up by sufficient research.
May Boost Your Immune System
Cat’s claw may support your immune system, possibly helping fight infections more effectively.
A small study in 27 men found that consuming 700 mg of cat's claw extract for 2 months increased their number of white blood cells, which are involved in combating infections ().
Another small study in four men given cat's claw extract for six weeks noted the same results ().
Cat’s claw seems to work both by boosting your immune response and calming an overactive immune system (, ).
Its anti-inflammatory properties could be responsible for its immune benefits ().
Despite these promising results, more research is needed.
May Relieve Symptoms of Osteoarthritis
Osteoarthritis is the most common joint condition in the United States, causing painful and stiff joints ().
In one study in 45 people with osteoarthritis in the knee, taking 100 mg of cat’s claw extract for 4 weeks resulted in reduced pain during physical activity. No side effects were reported.
However, there was no change in either pain at rest or knee swelling ().
In an eight-week study, a supplement of cat’s claw and maca root — a Peruvian medicinal plant — reduced pain and stiffness in people with osteoarthritis. In addition, participants needed pain medication less frequently ().
Another trial tested a daily mineral supplement alongside 100 mg of cat’s claw extract in people with osteoporosis. After 1–2 weeks, joint pain and function improved compared to those not taking the supplements ().
However, after eight weeks, the benefits were not sustained.
It should also be noted that it can be difficult to determine the specific actions of cat’s claw in studies that test multiple supplements at once.
Scientists believe that cat’s claw may ease osteoarthritis symptoms due to its anti-inflammatory properties (, ).
Keep in mind that more research is needed on cat’s claw and osteoarthritis ().
May Relieve Symptoms of Rheumatoid Arthritis
Rheumatoid arthritis is a long-term autoimmune condition that causes warm, swollen, painful joints. It is increasing in prevalence in the United States, where it affects more than 1.28 million adults ().
Some studies suggest that cat's claw can help relieve its symptoms.
For example, a study in 40 people with rheumatoid arthritis determined that 60 mg of cat’s claw extract per day alongside regular medication resulted in a 29% reduction in the number of painful joints compared to a control group ().
As with osteoarthritis, cat’s claw is thought to reduce inflammation in your body, easing rheumatoid arthritis symptoms as a result ().
Although these results are promising, the evidence is weak. Larger, better-quality studies are needed to confirm these benefits.
Summary Research suggests that cat’s claw extract may aid your immune system and reduce symptoms of osteoarthritis and rheumatoid arthritis. However, more studies are needed.
Cat’s claw contains several powerful compounds — such as phenolic acids, alkaloids, and flavonoids — that may promote health (, ).
However, there is currently not enough research to support many of its supposed benefits, including for the following conditions:
- viral infections
- high blood pressure
- stomach and bowel disorders
- ovarian cysts
Due to the lack of research, it’s unclear whether cat’s claw is an effective or safe treatment option for any of these ailments.
Summary Despite many marketing claims, there is insufficient evidence to support using cat’s claw for conditions like cancer, allergies, and AIDS.
While side effects of cat’s claw are rarely reported, available information to determine its overall safety is currently insufficient.
The high levels of tannins in cat’s claw may cause some side effects — including nausea, stomach upset, and diarrhea — if consumed in large amounts ().
Case reports and test-tube studies support other possible side effects, including low blood pressure, increased risk of bleeding, nerve damage, anti-estrogen effects, and adverse effects on kidney function (, , ).
That said, these symptoms are rare.
It is generally advised that the following groups of people should avoid or limit cat’s claw:
- Pregnant or breastfeeding women. Cat’s claw is not considered safe to take during pregnancy or breastfeeding due to a lack of safety information.
- People with certain medical conditions. Those with bleeding disorders, autoimmune disease, kidney disease, leukemia, problems with blood pressure, or who are awaiting surgery should avoid cat’s claw (, , ).
- People taking certain medications. As cat’s claw may interfere with some drugs, such as those for blood pressure, cholesterol, cancer, and blood clotting, you should speak to your doctor before taking it ().
The lack of safety evidence means that you should always use cat’s claw with caution.
Summary There is insufficient research into the risks of cat’s claw, although side effects are rare. Certain populations, such as pregnant women or those with particular medical conditions, should avoid cat’s claw.
If you decide to take cat’s claw, note that dosage guidelines have not been established.
However, WHO says that an average daily dose is 20–350 mg of dried stem bark for extracts or 300–500 mg for capsules, taken in 2–3 separate doses throughout the day (21).
Studies have used daily doses of 60 and 100 mg of cat’s claw extract for treating rheumatoid arthritis and osteoarthritis of the knee, respectively (, ).
One potential risk is that many herbal supplements — including cat’s claw — are not tightly regulated by the FDA. Therefore, it’s best to purchase cat’s claw from a reputable supplier to reduce the risk of contamination.
Look out for brands that have been independently tested by companies such as ConsumerLab.com, USP, or NSF International.
Summary Available information to develop dosage guidelines for cat's claw is insufficient. However, average daily doses range from 20–350 mg of dried bark extract or 300–500 mg in capsule form.
Cat’s claw is a popular herbal supplement derived from a tropical vine.
While research to support many of its supposed health benefits is limited, some evidence suggests that cat’s claw may help boost your immune system and ease symptoms of osteoarthritis and rheumatoid arthritis.
Because safety and dosage guidelines have not been established, it may be best to consult with your doctor before taking cat’s claw.