Tier A means regulatory approval and large human trials. Tier C means rodent data and nothing more. We say which one, every time — see our evidence-tier key.
33% of what we cover is Tier C. Most vendor sites in this category don't publish a number like this — we'd rather you see it than take our word for it.
This is educational content — mechanism, evidence, and honest limitations. For pricing or to order, see Products.
Extensive rodent work on tendon, ligament, muscle, and gut healing. No published human RCT exists.
Preclinical. Thymosin β4 itself (the full protein) has had some human trials in specific indications — ophthalmic and wound applications, for example. TB-500-the-fragment as sold is not the same molecule as the full protein studied — that distinction is one of the most commonly conflated facts in this category.
Real human data exists — for topical, cosmetic use. Studies on skin appearance, collagen, and wound healing. Widely used in legitimate cosmeceuticals. Injectable use has no comparable human trial evidence — what exists there is preclinical.
Large, well-run human RCT programmes. Regulatory approval in major markets for type 2 diabetes and, in specific formulations, weight management.
FDA approved (marketed as Vyleesi) for hypoactive sexual desire disorder in premenopausal women. Real trial data exists for that specific indication only.
FDA approved (marketed as Egrifta) for HIV-associated lipodystrophy. Genuine human trial data exists within that indication — it does not generalise to body-recomposition use, which is a different question the approval doesn't answer.
Approved in a number of countries (marketed as Zadaxin) for indications including hepatitis B, and as a vaccine adjuvant. Real clinical use outside the US, within specific indications.
Preclinical, plus limited early human pharmacology. No approval.
With DAC: binds albumin, greatly extended half-life.
Went into human obesity trials and largely failed to show significant weight loss versus placebo.
Not approved. Case reports in the literature associate use with changes to melanocytic naevi and concerns around melanoma, plus reported nausea, flushing, and product-quality issues tied to the unregulated supply chain.
Telomerase and longevity claims associated with this compound trace largely to a limited body of older research with methodological limitations and little independent replication. We say that plainly rather than repeating the claims.
*Approved for a narrow indication only — see the individual page. Approval for one use is not evidence for others.