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
What is cat's claw?
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.
Which part of the plant is used, and does it matter?
Most supplements use the inner bark of the vine. Some use root bark, which is harvested less sustainably because the plant does not regrow from it in the same way. The leaves are rarely used. It matters for two reasons: the compound content differs between plant parts, and bark harvesting allows the vine to survive. We prefer labels that state the plant part clearly, so you know what you are buying.
What does TOA-free mean on a cat's claw label?
Cat's claw contains two families of oxindole alkaloids, its main plant compounds: pentacyclic (POA) and tetracyclic (TOA). Plants differ naturally in how much of each they carry. A TOA-free product comes from bark selected to be very low in TOA, and the maker says so on the pack. It is a specification, not a guarantee of a stronger effect. Treat it as extra information when you compare two similar extracts.
Which form of cat's claw should I choose?
It depends on how precisely you want to dose and how you feel about the taste.
| Form | What it is | Suits |
|---|---|---|
| Standardised extract capsules | Concentrated bark, fixed alkaloid percentage | Consistent daily use |
| Milled bark capsules | Whole dried bark, not concentrated | Traditional, gentle approach |
| Tincture | Alcohol extract, dosed in drops | Flexible dosing, no capsules |
| Loose powder or tea | Bark to simmer or mix | Traditional preparation |
If you want to compare products fairly, stay within one form. Our liquid tinctures are the easiest place to start if you dislike swallowing capsules.
How much cat's claw do people usually take, and when?
There is no official reference intake for cat's claw, so follow the dose on the pack you choose. In practice, extract capsules usually sit in the low hundreds of milligrams per day, while milled bark products use larger amounts because they are not concentrated. Most people take it with a meal, which helps if the bitter taste of a tincture bothers them. Split doses across the day are common with higher amounts.
How long should I use it before I judge it?
Give it two to three weeks of consistent daily use. Botanical extracts rarely do anything noticeable on day one, and skipping days makes it impossible to tell whether the product is doing anything for you. Many people use cat's claw in blocks of a few weeks or months rather than continuously. If nothing has changed after a fair trial at the labelled dose, it is reasonable to stop rather than increase.
Can I combine cat's claw with other supplements?
Yes, and most people do. Cat's claw is commonly used alongside other bark and root extracts, or with a basic vitamin and mineral routine. Our practical advice: add one new botanical at a time. If you start three at once and something does not agree with you, you will not know which one to drop. Keep at least a week between additions so you can tell them apart.
Who should not take cat's claw?
Avoid it during pregnancy and breastfeeding, because there is not enough data on safety. It is also not intended for children. If you use prescription medication, particularly medicines that affect your immune system, blood pressure or blood clotting, check with your GP or pharmacist before starting, and mention it before planned surgery. Herbal extracts can interact with medication, so a short conversation up front is worth more than guesswork.
Is cat's claw allowed to carry health claims in the UK and EU?
No approved health claim exists for cat's claw. Claims for botanicals were submitted for assessment and many, including those for Uncaria tomentosa, were never authorised. That is why our product pages describe the plant, the species, the plant part and the extract strength instead of promising an effect. It also explains why some retailers use vague wording: without an approved claim, there is nothing specific they are permitted to state.
