TB-500: mass and molar amount
The molar mass of TB-500 is 889 g/mol. Everything on this page is computed from that figure, which was read from the public chemical record linked below.
Educational arithmetic only. Not medical advice and not a dosing protocol.
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This is educational arithmetic on figures entered by the reader. It is not medical advice, not a dosing protocol, and not a recommendation that anything be prepared, obtained or administered.
Nothing here states what quantity is appropriate for anyone, and there is no function in it that produces an amount to administer. A question about anyone’s health belongs with a licensed clinician who can examine the person asking.
Most compounds named here are research chemicals that are not approved by the FDA for human use. An exact calculation is not an accurate measurement: what is actually in a syringe depends on the preparation and the device, neither of which this page can see.
No qualified clinical reviewer is recorded against this site, and no credential is claimed anywhere on it. Full disclaimer.
| Mass | Nanomoles | Micromoles |
|---|---|---|
| 100 mcg | 112.49 | 0.1125 |
| 250 mcg | 281.21 | 0.2812 |
| 500 mcg | 562.43 | 0.5624 |
| 1 mg | 1124.86 | 1.1249 |
| 2 mg | 2249.72 | 2.2497 |
| 5 mg | 5624.30 | 5.6243 |
| 10 mg | 11248.59 | 11.2486 |
| Field | Value |
|---|---|
| Molar mass | 889 g/mol |
| Molecular formula | C38H68N10O14 |
| CAS number | 885340-08-9 |
| PubChem CID | 62707662 |
| Retrieved | 2026-10-09 |
| Mass of one nanomole | 0.88900 mcg |
Where these figures come from
Also recorded as TB500, thymosin beta 4 fragment 17-23, Ac-LKKTETQ. The molar mass, formula and identifiers above were read from the public chemical record (PubChem CID 62707662) on 2026-10-09. That record is the authority, not this page: it can change after the date it was retrieved, and the linked copy is the current version.
Regulatory register finding
A query of the FDA Drugs@FDA application register on 2026-10-09 returned no application records for this compound name. This compound is not approved by the FDA for human use.
That sentence records the result of an automated query against a public application register on 2026-10-09. It is not legal advice and is not a jurisdiction-by-jurisdiction assessment of anything.
What a molar amount does and does not tell you
Dividing a mass by the molar mass gives a count of molecules in a convenient unit. That is the only figure on which two different compounds can be compared at all, because a milligram of a light molecule contains far more molecules than a milligram of a heavy one.
It stops there. Equal molar amounts are not equal potency, equal activity, equal binding or equal anything else, and nothing about how TB-500 behaves follows from the arithmetic on this page.
The research record
This site does arithmetic and holds no research findings. What the published literature reports about TB-500, with citations and retrieval dates, is compiled on the research corpus: TB-500 on Peptide Monographs.
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