The study measured normal blood levels of two peptides, thymosin‑alpha‑1 and thymosin‑beta‑4, in a large group of healthy adults and gave average values and ranges. It found that thymosin‑alpha‑1 levels are about 540 pg/ml and don’t change with race, sex, or age, while thymosin‑beta‑4 averages 12.6 ng/ml, slightly rising with age but otherwise unchanged. These numbers serve as reference points for anyone who might test their own levels.

Enzyme linked immunosorbent assays were used to measure serum levels of immunoreactive thymosin alpha 1 and thymosin beta 4 in 681 healthy adults (range 18 yr-101 yr). Immunoreactive thymosin alpha 1 was found to occur at a geometric mean of 540 pg/ml with a range from 252 to 1158 pg/ml. There were no differences in the levels when analyzed according to race, sex or age. Immunoreactive thymosin beta 4 was measured at a geometric mean of 12.6 ng/ml with a range from 6.9 to 23.0 ng/ml. There were no differences in the levels when analyzed according to race or sex, however, there was a slight upward trend with increasing age. This data may be useful as a reference when monitoring clinical studies, determining the kinetics of drug metabolism and distinguishing patient groups with elevated levels of either of these peptides.