In general, I prefer single species or single strain probiotics that has studies on PubMed.  On occasion, a probiotic mixture makes it to my “second line probiotics to try”. There is a new pair on the market (one for men, one for women) that passes the bar.

What is my bar?

• All of the strains are human sourced
• A majority of strains have published studies showing benefits
• Reasonable cost 

Ideally, the probiotic should persist. This appears to NOT OCCUR with Seed, see  this update on the results after 2 months on Seed.

Seed

This is a new company whose probiotics are available for PRE-ORDER for $49.99/month with a 30 day guarantee (I believe this is a money back if no change)

Considering this is ~100 BCFU/day, the cost is very reasonable.

Female Version

Note that the country of origin is included in the strain designation.

Male Version

Bottom Line

This from a technical perspective, beats the pants off the typical health-food store probiotic mixture.

I grabbed one of the above strains (B. lactis SD-MB2409-IT) and did a little digging:

• Innovative probiotics and systemic bioactive metabolites. Anti-ageing potential (2012)
• Bacterial strains belonging to the genus for use in the treatment of hypercholesterolaemia (Patent – 2012)
• Bifidobacteria supplementation: effects on plasma lipid profiles in dyslipidemic children (2014)

The origin of some of these strains appear to be bart.pl, they have a very informative list of their strains to research studies PDF that can be downloaded here.

They do have a referral program, if you order via this link, I get free product (no cash).