Short answer: This guide covers four Natren strains: L. acidophilus NAS (Megadophilus, Healthy Trinity), B. bifidum Malyoth (Bifido Factor, Healthy Trinity), L. bulgaricus LB-51 (Digesta-Lac, Healthy Tummy, Gastro-pH) and B. infantis NLS (the Life Start family). Each Natren label lists the full strain name with a CFU count guaranteed through expiration.
Natren labels name each probiotic down to the strain: not just “acidophilus”, but Lactobacillus acidophilus NAS. This guide explains what those names mean and which Natren products use each strain, so you can read a label with confidence.
How to read a strain name
A full probiotic name has three parts:
- Genus, such as Lactobacillus or Bifidobacterium: the broad family.
- Species, such as acidophilus or bifidum: a group within that family.
- Strain designation, such as NAS or LB-51: one specific, identified culture within the species.
Two products can both list “L. acidophilus” and still contain different strains. The strain ID tells you exactly which one you're getting. Natren lists it on the label alongside the CFU count (colony-forming units), which is guaranteed through the expiration date.
Lactobacillus acidophilus NAS
NAS is Natren's acidophilus strain. You'll find it in:
- Megadophilus, Natren's single-strain NAS product, offered in dairy, dairy-free and vegan versions. Natren's product copy describes it as supporting digestive health and a healthy intestinal environment.*
- Healthy Trinity, alongside Malyoth and LB-51.
- Ultimate Vaginal Health Support, with 5 billion CFU of NAS per capsule.
- The Healthy Start System.
Read more: Lactobacillus acidophilus and the NAS strain.
Bifidobacterium bifidum Malyoth
Malyoth is Natren's B. bifidum strain. It's the single strain in Bifido Factor, which Natren's product copy describes as supporting regularity and colon health.* Malyoth is also in Healthy Trinity, where it's the largest declared count, and in the Healthy Start System.
Read more: Bifidobacterium bifidum and the Malyoth strain.
Lactobacillus bulgaricus LB-51
LB-51 is Natren's L. bulgaricus strain. It's in:
- Digesta-Lac, the single-strain LB-51 capsule, which Natren's product copy describes as supporting normal digestion of proteins.*
- Healthy Tummy (French vanilla) and Gastro-pH (strawberry) chewable wafers.
- Healthy Trinity and the Healthy Start System.
- Yogurt Starter, together with Streptococcus thermophilus BC 122.
Read more: Lactobacillus bulgaricus and the LB-51 strain.
Bifidobacterium infantis NLS
NLS is Natren's B. infantis strain. It's the strain in the Life Start family: Life Start, Life Start Vegan and Life Start 2. Natren describes Life Start as a powder for infants, toddlers and expecting mothers.
Read more: Bifidobacterium infantis and the NLS strain, and for parents, B. infantis for babies.
Single-strain or combined?
Natren offers both. Single-strain products (Megadophilus, Bifido Factor, Digesta-Lac) let you take each strain on its own schedule. The Healthy Start System packages those three in separate bottles so each can be taken as directed on its own label. Healthy Trinity combines NAS, Malyoth and LB-51 in one oil-based capsule. Which suits you is a personal choice; our product finder and free consultation can help.
Why storage matters
Every Natren product on this page should be kept refrigerated and not frozen; Natren guarantees label counts through the expiration date when they're stored as directed. Read more in our refrigeration guide.
Frequently asked questions
What do the letters after a probiotic's name mean?
They are the strain designation, such as NAS or LB-51, which identifies one specific culture within a species. Two products can both list “L. acidophilus” and still contain different strains.
What's the difference between Healthy Trinity and the Healthy Start System?
Healthy Trinity combines NAS, Malyoth and LB-51 in one oil-based capsule. The Healthy Start System packages Megadophilus, Bifido Factor and Digesta-Lac in separate bottles, so each can be taken as directed on its own label.
How should Natren probiotics be stored?
Refrigerated, not frozen. Natren guarantees label counts through the expiration date when products are stored as directed.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
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