How the four pathways differ

They are not interchangeable

The most common mistake in this field is treating these four as a menu of stronger and weaker versions of one idea. They differ in what the product physically is, where it comes from, how it is regulated and how much human evidence exists — and those differences do not line up in a single ranking.

What each one is

• Stem cells — living cells, autologous or donor-derived, sometimes culture-expanded. Only cord-blood-derived blood-forming cells are FDA-approved, and only for certain blood disorders.
• Exosomes / EVs — cell-free vesicles harvested from cell culture. No FDA-approved product exists in this category. Potency and dose have no standard unit.
• Peptides — synthesised signalling molecules. Some are fully approved medicines; many marketed in wellness settings are not approved for the advertised use.
• PRP / orthobiologics — your own blood, concentrated and reinjected the same day. The largest human trial literature of the four, concentrated in musculoskeletal conditions, with preparation differences that complicate pooling.

How to compare them honestly

Evidence maturity is specific to an indication, not to a pathway. PRP having a solid tendon literature says nothing about PRP for hair loss. A stem cell product with promising early data in one condition tells you nothing about the same product in another.

Ask the same structured questions of every pathway: what exactly is the product, where did it come from, what is the dose, what is its regulatory status here, and which studies used this product in patients like me. A provider who can answer those for one pathway and not another has told you something useful.

What Navigator does and does not do

Navigator separates two things that are often blurred. An Evidence Grade describes the maturity of published research for a treatment category under our stated methodology. A Transparency Score describes how much a provider documents and discloses. Neither is a safety rating, neither predicts your outcome, and a high score on either never means a treatment is effective for you.