Cat's Claw
Discover cat's claw supplements: capsules, tinctures and powdered bark from Uncaria tomentosa. We explain how standardised extracts differ, what TOA-free means and how to use cat's claw sensibly, day to day.Read more →
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Cat's claw bark: the forms, the standardisation and the honest limits
What cat's claw actually is
Cat's claw is the inner bark of Uncaria tomentosa, a woody climbing vine from the Amazon basin. The name comes from the curved thorns on its stems, which look like a cat's claws. In Peru the bark has been simmered into a drink for generations. In the UK you will mostly meet it as a dried bark extract in capsules, as an alcohol tincture, or as loose powder alongside the rest of our herbal supplements range.
Two plants share the name. Uncaria tomentosa is the species used in almost every supplement. Uncaria guianensis is a close relative with a different alkaloid profile. Labels do not always spell this out, so we check the Latin name on every pack we list.
Extract strength matters more than milligrams
A 1,000 mg capsule of plain milled bark is not comparable to a 300 mg extract standardised to a set percentage of alkaloids. The extract concentrates the plant compounds; the milled bark does not. That is why comparing products on total milligrams alone is misleading.
You will also see TOA-free on some labels. Cat's claw contains two groups of oxindole alkaloids: pentacyclic (POA) and tetracyclic (TOA). Some producers select bark from plants low in TOA and state this on the pack, because the two groups behave differently in the plant. Whether that distinction matters in practice is still debated, so we treat it as information, not as a selling point.
- Standardised extract in capsules: the most consistent dose from batch to batch.
- Tincture: flexible dosing by drops, with a strong bitter, woody taste.
- Milled bark or tea: closest to traditional use, hardest to dose precisely.
How we choose cat's claw at BONO
We look at three things: the species and plant part, the extract ratio or standardisation, and whether the dose on the label is realistic. We prefer products that name Uncaria tomentosa inner bark and state a clear extract strength, because that is the only way you can compare two jars. We skip vague "herbal blends" where cat's claw appears in a token amount you cannot measure. Every product passes our compliance team before it goes live, and we buy directly from the brands, so what is on the label is what is in the jar. Read how we select brands and products.
Who it suits, and what we will not promise
Cat's claw is a traditional botanical, not a vitamin with a settled reference intake. The European food safety authority (EFSA) has not approved any health claim for it, so we do not make one. What we can say honestly: people usually take it as part of a longer routine rather than for a quick effect, and most brands suggest giving it two to three weeks of consistent use before you judge anything. It is often bought alongside other bark and root extracts such as boswellia extracts or turmeric with curcumin, usually as a rotating part of a routine rather than all at once.
Cat's claw is not suitable during pregnancy or breastfeeding, because there is too little data. If you take prescription medication, especially anything that affects your immune system or blood clotting, speak to your GP or pharmacist first. That is not a reason to avoid the plant; it is a reason to check before you start.
Frequently asked questions
Cat's claw is the bark of Uncaria tomentosa, a climbing vine that grows in the Amazon rainforest. It gets its name from the hooked thorns along its stems. The inner bark, and sometimes the root, is dried and either milled or extracted. In South America it has a long tradition as a bark decoction. In supplements you find it as capsules, tablets, liquid tincture or loose powder.
