Immune System: How It Works, What Weakens It, and What You Can Do

When your body fights off a cold, a cut gets infected, or you feel run down after stress, that’s your immune system, the body’s defense network that identifies and destroys harmful invaders like viruses, bacteria, and abnormal cells. Also known as your body’s internal security force, it’s not just about getting sick less—it’s about keeping everything running smoothly, from your brain to your gut.

But your immune system doesn’t work alone. It’s deeply tied to inflammation, a natural response that turns harmful when it becomes chronic. Too much inflammation can trigger or worsen conditions like arthritis, heart disease, and even depression. That’s why studies show people with long-term inflammation are more likely to struggle with anxiety or low mood. It’s not just "in your head"—it’s in your biology. Your gut-brain axis, the two-way communication line between your digestive system and your brain plays a huge role here. About 70% of your immune cells live in your gut. If your gut flora is off balance from poor diet, antibiotics, or stress, your immune system gets confused. It might start attacking your own tissues, leading to autoimmune disorders, conditions where the body mistakenly targets healthy cells like lupus or rheumatoid arthritis. That’s why drugs like lenalidomide, originally used for cancer, are now being studied for lupus—they don’t just suppress the immune system, they help reset it.

And then there’s immunodeficiency, when the immune system doesn’t work well enough to protect you. It’s not just about rare genetic diseases. Chronic stress, lack of sleep, poor nutrition, or even long-term use of certain medications can weaken your defenses. People with immunodeficiency don’t just get sick more often—they’re also at higher risk for mental health issues. The same inflammation that damages your body can mess with your brain chemistry. That’s why some patients on immune-modulating drugs report mood changes, even if their physical symptoms improve.

What you’ll find below isn’t just a list of drug comparisons. These are real stories and data-driven guides about how medications interact with your immune system. From how Flovent reduces airway inflammation in asthma, to how tibolone might trigger migraines by affecting immune signaling, to how immunodeficiency links to depression—each post connects the dots between what you take and how your body responds. You won’t find fluff here. Just clear, practical info on what works, what doesn’t, and why it matters for your daily health.