Why Now Is the Best Time to Strengthen Your Immune System

by Planet 3 Vitamin Packs June 26, 2025

As summer unfolds with its steady sunshine and relaxed pace, it offers more than seasonal enjoyment—it provides a vital window to prepare your immune system for the respiratory viruses that arrive in full force come fall.

According to data from the Centers for Disease Control and Prevention, respiratory illnesses like colds, influenza, and RSV begin circulating significantly as early as September, with incidence peaking between December and February. Yet many individuals wait until the first sneeze before acting—a response that may be too late.

A Verified Health Reminder: “You Can’t Boost Immunity Overnight”

Mayo Clinic family medicine physician Dr. Stephen McMullan offers a clear reminder: “Your immune system requires care and is not something you can give a lasting boost overnight, so don’t rush to the cabinet for pills or powders.” This underscores what scientists have repeatedly confirmed: immune resilience is built gradually, not instantly.

Supplements That Need a Summer Head Start

Vitamin D supports both innate and adaptive immune responses. Regular supplementation reduces respiratory infection risk, particularly in those with low baseline levels. Because it builds slowly in the bloodstream, summer is the ideal time to optimize levels.
Vitamin C has been shown to shorten cold duration when taken consistently—especially at doses above 200 mg.
Zinc can reduce the length of cold symptoms when taken early, but maintaining zinc levels through daily intake allows the body to respond faster.
Elderberry extract, used at the onset of illness, has demonstrated benefits in reducing symptom duration in clinical trials.
Probiotics and omega‑3 fatty acids also support immune health by regulating inflammation and supporting the gut’s role in immunity. These benefits require ongoing intake over time.

Lifestyle Foundations: Complement Your Supplements

In addition to nutrients, core health behaviors help prime the immune system:

Sleep: 7–9 hours per night improves immune cell function and lowers inflammation.
Exercise: Moderate movement enhances circulation of immune cells.
Stress reduction: Chronic stress impairs immunity. Mindfulness and time outdoors can help.
Diet: Fresh fruits, vegetables, and whole foods provide antioxidants and micronutrients essential to immune balance.

Summer provides the time, energy, and sunlight to develop these habits in a sustainable way.

Think of Your Immune System Like Marathon Training

Just as you wouldn’t run a marathon without training for months, you can’t expect your immune system to perform well without preparation. Fall won’t wait—and neither will the viruses that come with it.

The Bottom Line

Cold and flu season begins ramping up in early fall, but the groundwork for stronger immune defense starts now. By focusing on vitamins D and C, zinc, elderberry, probiotics, omega‑3s, sleep, stress management, and diet, you give your body the tools it needs to respond faster and more effectively.

For those looking for a convenient way to stay consistent, Planet 3 Vitamin Packs include all of these clinically backed nutrients—pre-dosed into one simple daily pack—making it easier than ever to stay on track through summer and beyond.

Sources

Martineau AR et al., “Vitamin D supplementation to prevent acute respiratory infections,” BMJ, 2017
Hemilä H., “Vitamin C for preventing and treating the common cold,” Cochrane Database of Systematic Reviews, 2013
Singh M, Das RR. “Zinc for the common cold,” Open Respiratory Medicine Journal, 2012
Tiralongo E et al., “Elderberry supplementation reduces cold duration in air travelers,” Nutrients, 2016
Lenoir-Wijnkoop I et al., “Probiotics and respiratory tract infections,” Frontiers in Nutrition, 2020
Calder PC et al., “Omega-3 fatty acids and immune function,” Journal of Clinical Medicine, 2022
Mayo Clinic News Network, “How to maintain a healthy immune system,” 2023
CDC, “Influenza Surveillance Reports and Cold Season Data,” 2024
National Institutes of Health – Office of Dietary Supplements: Vitamin D, Zinc, and Probiotics fact sheets
Harvard Health Publishing, “Should you take vitamin C or zinc for your cold?” 2023