5 Reasons Andean Healers Have Trusted Cat's Claw for 2,000 Years

May 31, 2026

Walk into a Lima herbal shop and ask for help with joint pain or a sluggish immune system. There's a decent chance the shopkeeper will hand you a bag of woody bark shavings and say one word: uña de gato. Cat's Claw.

The plant has been part of Asháninka and Shipibo medicine for at least two thousand years, possibly longer. Spanish chronicles from the 1500s mention it. Researchers in Vienna started looking at it seriously in the 1970s. Today you can find capsules in pharmacies from Iquitos to Madrid, but most people in the U.S. still don't know what it actually does.

Here are five reasons the herb stuck around, and where the modern evidence sits.

1. Two thousand years of pain relief in the Amazon

Cat's Claw grows as a thick woody vine in the rainforests of Loreto and Madre de Dios. The hooks on its stems give it the name (they actually do look like a cat's claws if you've ever pulled one off a branch). Indigenous healers boil the inner bark for hours, then drink the resulting reddish-brown decoction for arthritis, stomach trouble, recovery from childbirth, and wounds that won't close.

That's not folklore someone made up last week. The Asháninka have a specific name for it (saventaro) and a specific preparation method, passed down through generations of curanderos. When something survives for that long in a culture without books or labs, it usually has at least one job it does well.

2. Specific compounds researchers can point to

This is where Cat's Claw stops being mysterious. Two main groups of alkaloids do the heavy lifting: pentacyclic oxindole alkaloids (POAs) and tetracyclic oxindole alkaloids (TOAs). The POAs appear to modulate immune cell activity. The TOAs seem to work on the central nervous system, sometimes in ways that conflict with the POAs.

That matters because not every Cat's Claw plant has the same ratio. Some have more TOAs, some have more POAs, and a 2001 paper in Phytomedicine flagged that mixing them can cancel out the benefits. Reputable suppliers chemotype the bark, meaning they test which compounds are actually in there before bottling. That's a quiet detail most labels won't mention, but it's worth asking about.

3. The arthritis study people keep citing

In 2002, a small randomized trial published in the Journal of Rheumatology gave 40 patients with active rheumatoid arthritis a Cat's Claw extract for 24 weeks. The treatment group had fewer painful joints than the placebo group. It was a small study, the extract was a specific freeze-dried preparation, and the effect size was modest. Honest answer: encouraging, not conclusive.

A 2001 trial in the same journal looked at osteoarthritis of the knee, with similar mild improvements in pain and function over four weeks. Both studies used standardized extracts, and neither showed serious safety problems at the doses tested. Most reviews since then have called for larger trials, which haven't really happened. Funding for herb research is thin.

4. Immune modulation, not immune boosting

You see "immune boost" on every Cat's Claw label, and it's a sloppy phrase. The herb doesn't crank your immune system to maximum. Lab work going back to the 1990s suggests the POAs may help white blood cells respond more efficiently to actual threats. Closer to tuning than amplifying.

For someone with an autoimmune condition where the immune system is already overactive, an indiscriminate "boost" would be the wrong thing. Cat's Claw is one of the few traditional herbs that gets studied in both directions. We're not making medical claims here, but the mechanism is more interesting than the marketing suggests.

5. It plays well with daily routines

A lot of traditional herbs taste like punishment. Cat's Claw bark tea is bitter and earthy, but it's drinkable with a little ginger or a slice of lemon. Capsules skip the taste question entirely, which is why most people in the U.S. use them. A typical serving is 500 to 1,000 mg of bark powder once or twice a day, taken with food.

You don't need to cycle off it (no good evidence either way), and there's no caffeine, so it won't interfere with sleep. Most people who try it for joint stiffness say they notice something at week three or four, not day one. Patience matters.

A few honest cautions

Cat's Claw can interact with blood thinners and with drugs metabolized by the liver. Skip it if you're pregnant or nursing, on immunosuppressants after a transplant, or scheduled for surgery in the next two weeks. Anyone on prescription medication should talk to a pharmacist before starting it. The herb is generally well tolerated, but "well tolerated" doesn't mean "free of interactions."

What we carry

We work with a Peruvian supplier who tests for POA content and sources bark from sustainably harvested vines in the Loreto region. The capsules are 100% bark, no fillers, no proprietary blends hiding the dosage. If you'd rather brew it than swallow it, our Cat's Claw Tea is the same bark in tea-bag form. You can also browse the full supplement collection for related Amazonian herbs like Graviola and Chanca Piedra.