What low Secretory IgA means, and how to raise it
Secretory IgA is the first line of immune defense in the gut mucosa.
What is Secretory IgA?
Secretory IgA (sIgA) is your gut's primary antibody. It is the first line of immune defense in the mucosal layer. Specialized immune cells in your gut wall produce it continuously and pump it into the lumen, where it binds to and neutralizes pathogens, toxins, and food antigens before they ever reach your gut cells. Adults produce several grams of sIgA per day. It is the most abundant antibody in the body by mass. Low stool sIgA usually indicates depleted mucosal immunity. Common drivers are chronic stress (cortisol directly suppresses sIgA production), poor sleep, prolonged antibiotic use, chronic gut inflammation, and persistent infection. Confusingly, very high sIgA is also a flag. It can mean active immune challenge from an ongoing infection. The optimal range is moderate. sIgA is one of the most modifiable markers on a gut test. Lifestyle changes (sleep, stress, fermented foods, colostrum) reliably move it within 4 to 6 weeks.
What does low Secretory IgA indicate?
Secretory IgA is the first line of immune defense in the gut mucosa. Low levels indicate depleted mucosal immunity, often linked to chronic stress, poor sleep, or prolonged gut inflammation. Colostrum and specific fermented foods have been shown to raise sIgA levels over 4–6 weeks.
Symptoms commonly reported
- frequent infections
- frequent colds
- food sensitivities
- chronic stress symptoms
- post-illness fatigue that lingers
- skin issues
- recurrent yeast infections
Not everyone with this finding has every symptom. Many people have several without realizing they share a root cause.
Reference ranges
A value just over the threshold is usually less urgent than a value many times outside the range. Trend across retests matters more than a single number.
The 6-week protocol for low Secretory IgA
A phased plan with 11 food prescriptions across three phases. Below is the first phase preview. Upload your lab to unlock the full protocol with exact quantities, frequencies, and conflict-resolved sequencing.
- Bovine colostrum powder See your personalized dose
- Kefir (full-fat, plain) See your personalized dose
Unlock your full personalized protocol
Most people have 4 to 7 abnormal markers on a single test. Upload your PDF and we'll build the 6-week protocol that handles all of them in the right order, with conflicts resolved and a grocery list ready to send to Instacart or Kroger.
Upload my lab PDFWhich tests measure Secretory IgA?
- GI-MAP (Diagnostic Solutions)
- Genova GI-Effects
- Doctor's Data GI360
Different labs use different methodologies (qPCR, 16S sequencing, shotgun metagenomics), so absolute numbers may not be directly comparable across tests. We accept GI-MAP, Genova GI-Effects, and Biomesight PDF uploads today.
