Is thermal paste toxic? Accidentally eat it?

One friend of mine asked me if CPU thermal paste is poisonous? Although I have worked with computers for a long time, I didn’t know the answer, so I started looking online. I was surprised and ridiculed by the abundance of responses in which people were pranking poor people that eat some thermal paste.

So I decided to delve into this issue and help a friend calm down.


I am not a doctor. I just did research and talked with some chemist’s friends.

Short answer

Yes, it contains toxic heavy metals, but it depends on the amount. If you eat the remaining thermal paste under the nail, you can rest easy; that amount is not enough for poisoning. But if you are still worried, go to the hospital.

What is a thermal paste made of?

Nowadays, there are many different thermal pastes. Let’s try to discuss some of the most popular.

Thermal Grizzly Kryonaut

Kryonaut composition: is a silicone-based paste, which allows more aluminum in its mixture, providing better thermal performance and lower operating temperatures. Kryonaut also has a combination of metals like tin, gallium, and indium.

  • Silicone – nontoxic, is a lab-made material that consists of several different chemicals, including silicon, oxygen, carbon, and hydrogen. “Because silicone is considered chemically stable, experts say it’s safe to use and likely not toxic.”.
  • Tin – low toxicity, “nausea, vomiting, and diarrhea have been reported after ingesting canned food containing 200 mg/kg of tin.”
  • Gallium may be toxic, “Although it is not harmful in small amounts, gallium should not be purposefully consumed in large doses.
  • Indiumnontoxic,If swallowed, no specific intervention is indicated as this material is not likely to be hazardous by ingestion. However, if you feel unwell or are concerned, get medical advice/attention.

Noctua NT-H1 3.5g

Noctua NT-H1 composition: is a synthetic oil mixture that contains some hazardous ingredients like Aluminum-powder (pyrophor) and Zinc oxide.

  • Aluminum-powder (pyrophor)low toxicity, “after swallowing: If symptoms persist consult doctor.”
  • Zinc oxidelow toxicity, “Zinc oxide is not very poisonous if it is eaten. Long-term recovery is very likely. However, people who have had long-term exposure to metal fumes may develop serious lung disease.”

Arctic Silver 5 AS5-3.5G

Artic Silver 5 composition: contains 99.9% pure silver (pure micronized silver) and 0.1% sub-micron zinc oxide, aluminum oxide and boron nitride particles and does not does not contain any silicone.

  • Pure silvermay be toxic, “study found that reproductive tissues were damaged in animals after they received injections of silver nitrate. However, the tissues recovered even while the animals received more injections of silver nitrate. Tests in animals show that silver compounds are likely to be life threatening for humans only when large amounts (that is, grams) are swallower and that skin contact with silver compounds is very unlikely to be life threatening.” Remember that a full tube contains about 3.5 g.
  • Zinc oxidelow toxicity, “Zinc oxide is not very poisonous if it is eaten. Long-term recovery is very likely. However, people who have had long-term exposure to metal fumes may develop serious lung disease.”
  • Aluminum oxidelow toxicity, Aluminium oxides rank amongst the less toxic substances and only exhibit toxic effects in high concentrations.
  • Boron nitridetoxic, “May damage fertility. May dame the unborn child. After swallowing: Rinse mouth. Do not induce vomiting; call for medical help immediately.

How do I know if I have heavy metal poisoning?

The early symptoms can be overlooked due to the fact that they are not always specific. In excess exposure, and the damage to multiple organs could be experienced even if the person is not showing any symptoms. A few indications and symptoms of poisoning with metals include:

  • Abdominal pain, nausea, vomiting, and diarrhea (the hallmark symptoms with most cases of acute metal ingestion)
  • Dehydration
  • Heart abnormalities such as cardiomyopathy or abnormal heart beat (dysrhythmia)
  • Nervous system symptoms (e.g. numbness, tingling of hands and feet, and weakness)
  • Anemia (a classic symptom of chronic metal exposure)
  • Kidney damage
  • Liver damage
  • Lung irritation, or fluid accumulation (edema)
  • Brain dysfunction such as memory loss
  • Horizontal lines on the nails
  • Changes in behavior
  • Malformed bones in children, or weakened bones
  • Miscarriage or premature labor in pregnant women

The most prevalent metals humans can take in toxic quantities are:

  • mercury
  • lead
  • cadmium
  • arsenic

Such materials are not used in the most popular thermal pastes.

There are no known cases of man being poisoned by heavy metals that are in thermal paste.

What to do in case of heavy metal poisoning?

poisoned on heavy metals first aid

Contact with the skin

Contact with the skin is not a cause for concern. There are there are no first-aid measures to be taken. If irritation to the skin occurs following prolonged exposure, rinse using soap and warm water.

Contact with your eyes

After contact with your eyes, wash your eyes with clean water right away. Seek medical advice if irritation persists.

After swallowing

Rinse mouth and consult a doctor. Avoid vomiting.

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Many heavy metals are found in food, for example, rice (contains arsenic), fish (can contain mercury), etc.

The amount of toxic heavy metals in thermal paste is very small or almost non-existent, so do not panic and get scared after eating a small amount of thermal paste.

To be harmful to the body, you need to eat thermal paste regularly and in large quantities to be poisonous. But if you feel anxious, go to the hospital.

If something similar happened to you or you have other information, you can always leave a comment in the comments section.

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