CD38 is a protein found on the surface of many cells, but in cancer—and especially in exhausted or overworked immune cells—it becomes a serious problem. Cancer cells and dysfunctional immune cells often produce too much CD38, and this throws off the immune system’s ability to fight effectively.

One of the worst things CD38 does is destroy something called NAD⁺. NAD⁺ is essential fuel for immune cells, especially T-cells and natural killer (NK) cells, which are the body’s frontline soldiers against cancer. When CD38 is high, NAD⁺ drops, and immune cells become tired, sluggish, and confused. This makes it easier for cancer to escape detection and attack.

But there are powerful tools that can lower CD38 and help restore your immune system’s energy. One of the most effective is apigenin, a natural compound found in parsley, chamomile, and in concentrated supplement form. Apigenin works by blocking the internal signals that tell cells to produce CD38. When these signals are shut down, less CD38 is made—and NAD⁺ levels can rise again. This re-energizes your T-cells, helping them stay alert, mobile, and aggressive toward cancer cells.

Another helpful compound is fisetin, a plant-based nutrient found in strawberries and other fruits. Fisetin works similarly to apigenin. It suppresses the same CD38-producing signals inside the cell and protects healthy cells from damage. It also supports sirtuins, which are proteins that use NAD⁺ to keep cells youthful, resilient, and strong. With CD38 down and NAD⁺ up, your immune system can recover its strength and focus.

Quercetin is a third powerful player in this strategy. Found naturally in onions and apples, quercetin also blocks the pathways that tell cells to create CD38. By lowering CD38 levels, quercetin helps immune cells function at full capacity—and also makes cancer cells more sensitive to radiation and other therapies. Without CD38 to hide behind, cancer cells are easier targets.

In addition to supplements, fasting is one of the most natural and powerful ways to reduce CD38. When you stop eating for many hours or days, your body shifts from growth mode to repair mode. During this state, CD38 production drops, NAD⁺ levels rise, and a process called autophagy kicks in. Autophagy is like a cleanup crew—it recycles broken or dangerous cells, including those producing too much CD38. Fasting also reduces inflammation, which helps keep CD38 turned off longer. It’s like cutting the power to cancer’s defense shield and giving your immune system a chance to reload.

Eating a low-protein diet also helps. Cancer cells need protein—especially amino acids like methionine and glutamine—to grow and produce things like CD38. If you limit protein, cancer struggles to maintain its shield. Meanwhile, your healthy immune cells can adapt and often become even more efficient. Low protein also increases autophagy, accelerating the removal of damaged or harmful cells.

When combined—apigenin, fisetin, quercetin, fasting, and low protein—this approach forms a powerful anti-cancer strategy. It takes away cancer’s armor by lowering CD38, and it recharges your immune army by boosting NAD⁺. T-cells and NK cells stay sharp, energized, and aggressive. This gives your body a much better chance to find, target, and destroy cancer. At the same time, it makes radiation and other treatments more effective, since the cancer can no longer hide behind chemical defenses.

This strategy flips the battlefield: it drains cancer’s strength while restoring your own, allowing your immune system to lead the attack.