Why You’re Not Seeing Results from Your Supplements: Bioavailability Explained

Learn How Bioavailability Impacts the Way Your Body Absorbs Nutrients

If you’ve been taking supplements but not seeing the results you expect, the issue may not be the dosage—but how well your body absorbs them.

This concept is known as bioavailability, and it plays a critical role in how effective your supplements are. Even if you’re using high-quality products, poor absorption can prevent you from reaping their full benefits.

In this blog, we’ll explore the key factors that impact bioavailability and share simple, practical tips to help you get the most from your supplement routine.

What Is Bioavailability?

Bioavailability refers to the amount of a nutrient your body actually absorbs and utilizes after ingestion. Just because a label says it contains 200 mg of magnesium doesn’t mean your body is absorbing anywhere close to that amount.

From formulation and delivery method to digestive health and timing, many factors can influence bioavailability—and ultimately, your results.

Key Factors That Influence Supplement Absorption

1. Nutrient Form Matters

The form a nutrient comes in can significantly impact how well your body absorbs it. Here are a few examples:

Magnesium: Magnesium glycinate is more bioavailable and easier on digestion than magnesium oxide. (1)

Vitamin B6: The common form, pyridoxine hydrochloride (PNH), must be converted to its active form (P5P). Many people have trouble making this conversion, especially if they have genetic variants or liver issues—making P5P the better option. (2)
Iron: Heme iron (from animal sources) is far more bioavailable than non-heme iron (from plants), which often needs vitamin C to aid absorption. (3)
Calcium: Calcium citrate is better absorbed than calcium carbonate, especially for those with low stomach acid.. (4)
Curcumin: This antioxidant from turmeric is poorly absorbed unless combined with black pepper (piperine) or delivered in liposomal form. (5)
Folate: People with MTHFR mutations often cannot convert folic acid (synthetic) to its active form. Methylfolate bypasses this issue, offering superior bioavailability. (6)

2. Delivery Method

How a supplement is delivered matters just as much as what’s in it.

Nutrients like CBD, glutathione, and fat-soluble vitamins (A, D, E, K) have absorption challenges due to their molecular structure. (7)

Vitamin C is water-soluble and quickly excreted, especially in high doses. Absorption drops significantly when taken in amounts over 1 gram. (8)

✅ Solution: Liposomal supplements wrap nutrients in tiny fat bubbles (liposomes), allowing for better absorption and cellular delivery. This method is especially useful for challenging nutrients like curcumin, glutathione, and vitamin C. (9)

Probiotics: Traditional strains often die in the acidic stomach. Spore-based probiotics, on the other hand, have a resilient outer shell that allows them to survive the journey and colonize the gut effectively. (10)

3. Digestive Health

You can take the best supplements on the market, but if your digestion is impaired, absorption will be too.

Common issues that reduce nutrient absorption:

Low stomach acid
Gut dysbiosis
leaky gut
Malabsorption conditions (like SIBO or celiac)

Improving gut health with digestive enzymes, bitters, probiotics, or stomach acid support can significantly improve nutrient uptake. (11)

4. Timing and Interactions

When and how you take your supplements can influence their effectiveness:

Fat-soluble vitamins (A, D, E, K): Take with meals that contain fat.
Mineral competition: Calcium and magnesium, or zinc and copper, can interfere with each other when taken together.
Synergistic nutrients: Vitamin D works best with magnesium and vitamin K2. B12 requires adequate stomach acid.
Circadian timing: Magnesium is calming—best taken at night. B vitamins are energizing—take them in the morning. (12)

5. Watch Out for Additives

Many store-bought supplements contain fillers, binders, artificial colors, and coatings that can interfere with nutrient absorption—or even cause digestive issues. (13)

Opting for clean, third-party-tested, additive-free products helps protect your gut lining and maximize bioavailability.

Why "One-Size-Fits-All" Supplements Don't Work: The Importance of Proper Dosing

Most multivitamins and greens powders offer small amounts of many nutrients, but these generalized doses often aren’t enough to address your specific needs. Everyone’s biochemistry is different.

A better approach? Work with a functional medicine provider to assess what you’re actually deficient in—and why.

Through advanced lab testing and health history analysis, you can customize your supplement regimen to deliver exactly what your body needs for optimal function.

Tailor Supplementation to Individual Needs

Your supplement needs are as unique as your fingerprint. Here's why personalization is key:

One person may thrive on 600 mg of magnesium citrate, while another may experience digestive discomfort and need magnesium glycinate instead.
Two people with the same MTHFR gene mutation may have different levels of absorption or cofactor needs.
Another person may have oxidative stress and think they need antioxidants—but in reality, their detox pathways are blocked and need support first.

Working with a functional medicine provider ensures your supplement plan targets the root cause of your health concerns—not just the symptoms.

Optimize Your Supplement Routine with a Personalized Approach

At Denver Sports and Holistic Medicine, Dr. Martina Sturm partners with you to identify your body’s specific deficiencies, toxicities, and metabolic patterns. Using functional lab testing and a comprehensive health assessment, we create a personalized supplement protocol tailored to your needs.

Whether you're dealing with low energy, poor digestion, hormone imbalances, or chronic inflammation, we’ll help you absorb your supplements better—and feel better, faster.

Ready to Elevate Your Health?

Request a free 15-minute consultation with Dr. Martina Sturm at Denver Sports and Holistic Medicine today.

Let us help you uncover what your body truly needs—and why—so your supplement routine delivers real results.

Resources

Nutrition, Longevity, Functional medicine, Digestive HealthMartina SturmJanuary 1, 2025Denver Sports and Holistic Medicine supplement absorption, bioavailability, liposomal supplements, personalized supplements, functional medicine, nutrient deficiencies, clean supplements, digestive health, supplement timing, optimize supplement routine