“Lactanza ® hereditum ® is a dietary supplement based on Lactobacillus fermentum Lc40 (CECT5716), a strain found naturally in breast milk. It is the first probiotic that contributes to the balance of the mammary flora.
The administration of Lactobacillus fermentum Lc40 (CECT5716) reduces the bacterial concentration of Staphylococcus in the mammary flora and helps to restore its balance, allowing a more comfortable and healthy lactation, and reducing the recurrence rate in mastitis 31,32 . This helps to maintain lactation since mastitis is the main medical cause of premature and unwanted abandonment of breastfeeding 23 .”
There are 20+ studies on this specific strain on PubMed ranking it as one of the most studies probiotic at the strain level.
- A synbiotic composed of Lactobacillus fermentum CECT5716 and FOS prevents the development of fatty acid liver and glycemic alterations in rats fed a high fructose diet associated with changes in the microbiota .
- [Lactobacillus fermentum CECT5716 – probiotic from human milk with interesting properties] .
- Lactobacillus fermentum CECT 5716 Reduces Staphylococcus Load in the Breastmilk of Lactating Mothers Suffering Breast Pain: A Randomized Controlled Trial. 
- “Long-term administration of probiotics reduced systolic blood pressure.” 
- The viability of Lactobacillus fermentum CECT5716 is not essential to exert intestinal anti-inflammatory properties .
- Human milk probiotic Lactobacillus fermentum CECT5716 reduces the incidence of gastrointestinal and upper respiratory tract infections in infants .
- Oral intake of Lactobacillus fermentum CECT5716 enhances the effects of influenza vaccination. 
- Two Lactobacillus strains, isolated from breast milk, differently modulate the immune response .
- “Therefore, in general, the effect of Lact. fermentum CECT5716 is immunostimulatory in contrast to the anti-inflammatory effect of Lact. salivarius CECT5713.” 
- “Pretreatment with L. fermentum CECT 5716 attenuates trinitrobencene sulfonic acid colitis, an effect that seems to be due to its antioxidant abilities. When administered after trinitrobencene sulfonic acid , this probiotic is also effective in accelerating colitis recovery, and this is associated with an enhanced Toll-like receptor function.” 
This is human sourced, like Lactobacillus Fermentum ME3 , and appear to have similar characteristics. It is well studies.