NK (natural killer) cells: what they are and what is being studied
NK cells are a type of white blood cell of the innate immune system that recognize and destroy infected or tumor cells. They are being studied as a therapy, mainly in cancer, and their clinical use outside research is limited.
State of the evidence
Under investigation
There are clinical trials with NK cells in different types of cancer and diseases, but it is not a standard treatment.
Educational information prepared by Dr. Belinda Martínez, physician and surgeon. Last updated: October 3, 2026. It does not replace an assessment by a doctor.
What are NK cells?
NK stands for "natural killer". They are lymphocytes that, without prior sensitization, detect altered cells, such as virus-infected cells or some tumor cells, and eliminate them. They are part of the body's first line of defense.
How they are being studied as a therapy
In clinical trials, NK cells are obtained from the patient or a donor, expanded in the lab and infused, sometimes genetically modified. They are being evaluated mainly in leukemias and solid tumors, and compared with other treatments.
- Results so far are variable and depend on the type of cancer and the technique.
- They are not a standard treatment for cancer or for prevention.
- Their use should take place within research protocols or centers with the corresponding authorization.
Be careful with offers
If you are offered a way to "activate" or "boost" your NK cells to prevent disease or cure cancer, ask for published evidence and health authorization. There are no studies proving those benefits.
What to ask before accepting a treatment
With any biological therapy, it is worth asking these questions and expecting clear, written answers:
- Does it have health authorization for this use? In Mexico, products and procedures involving human cells are regulated by COFEPRIS; you can ask for proof.
- Are there published studies in people with my condition? What results did they show?
- What are the risks and what conventional alternatives exist?
- Who administers it, with what training and in what facility?
- What is the total cost and what happens if it does not work?
When to see a doctor
Seek medical care soon if you have any of these signs:
- Fever, chills or feeling very unwell after a procedure.
- Spreading redness, warmth, pus or increasing pain at the application site.
- Allergic reaction: hives, swelling of the lips or face, difficulty breathing.
- Severe pain that does not improve or gets worse over the days.
Frequently asked questions
Can NK cells be "boosted" with supplements?
There is no solid evidence that supplements increase NK cells in a clinically significant way. Adequate exercise and sleep influence immune health in general.
Do NK therapies cure cancer?
They have not been shown to be an established curative treatment. They are being studied in trials, usually alongside other treatments.
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Dr. Belinda Martínez reviews your case at her office in Guadalajara. The assessment is free of charge and does not commit you to any treatment.
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This content is informational and educational; it is not a diagnosis or a treatment recommendation. If you have any symptoms, consult a health professional.