What is Climbing Chalk?


Climbers use climbing chalk to keep their hands dry during bouldering. Clammy hands make it difficult to keep a grip on climbing holds. Climbing chalk is also known as magnesium, chalk or climbing lime. The chemical name is MgCO3 (magnesium carbonate). Magnesium is also used for extra grip in sports such as gymnastics and weightlifting.


Climbing chalk is usually available in the form of white powder. The powder is porous and easily absorbs moisture. You lubricate your hands with a layer of chalk and the climbing chalk will absorb the sweat from your hands. This will make your hands stiffer for climbing holds and improve the grip.

Climbing chalk as a white powder

Climbing chalk for bouldering also comes as magnesium blocks or chalk balls. Usually loose powder is sold in the bouldering hall. You also have different versions; coarse and fine powder. Sometimes there may still be blocks of climbing chalk in a bag. You can easily break these blocks into finer pieces. The bags are often sold as a 200 to 500 gram quantity. Prices may differ depending on the supplier.


Climbing chalk is often produced by mining magnesium minerals in the earth. It is then processed so that pure magnesium carbonate remains. Another method of production is making magnesium carbonate using sea water. This form of production is more environmentally friendly, but more expensive.


You will notice that it differs per person in the use of climbing chalk. Some people don't suffer from clammy hands while bouldering and others puff every minute.

How does climbing chalk work?

Climbing chalk, typically made of magnesium carbonate, is used by climbers to improve grip and reduce moisture on their hands. Here's how climbing chalk works:

1. Absorbs moisture: Climbing chalk has excellent moisture-absorbing properties. When climbers apply chalk to their hands, it helps to absorb sweat, oils, and moisture, keeping the skin dry and enhancing friction between the hand and the climbing surface.

2. Dries the skin: By absorbing moisture, climbing chalk helps to dry the skin on the hands. This is beneficial because moist hands can become slippery and reduce grip strength, making it more difficult to hold onto climbing holds or objects.

3. Creates friction: The dry chalk on the hands creates a friction-enhancing layer between the skin and the climbing surface. This increased friction allows climbers to maintain a stronger grip, particularly on holds and surfaces that may be smooth or challenging to grasp.

4. Reduces moisture-related issues: Chalk can help reduce the likelihood of blisters and other moisture-related problems. When hands are dry and free of excess moisture, there is less chance of the skin softening, which can lead to painful blisters or discomfort during climbing.

It's important to note that while climbing chalk enhances grip, it does not replace proper climbing technique or skill. Climbers still need to develop strength, technique, and overall proficiency to navigate climbing routes safely and effectively.

Overall, climbing chalk acts as a drying and friction-enhancing agent, allowing climbers to maintain a better grip and control while climbing. It is a useful tool in the climbing world and is widely used by climbers of all levels.