To determine the effect of oral testosterone supplementation on systemic low-grade inflammation measured by high-sensitive C-reactive protein (hs-CRP) in aging men with low testosterone levels.

Two hundred thirty-seven men aged 60 to 80 years with a testosterone level of <13.7 nmol/L (below the 50th percentile of the population distribution) were recruited into a double-blind randomized placebo-controlled trial. Participants were randomized to either 4 capsules of 40 mg testosterone undecanoate (Andriol Testocaps, NV Organon, Oss, The Netherlands) or placebo daily for 26 weeks. Serum levels of hs-CRP were measured at baseline and at 26 weeks using a near-infrared particle immunoassay of the Synchron LX System (Beckman Coulter, Fullteron, CA).

The median baseline hs-CRP level was 1.95 mg/L (0.30-6.43) in the testosterone group compared with 1.90 mg/L (0.40-5.91) in the placebo group. After 26 weeks of testosterone supplementation therapy, the 2 intervention groups were not statistically significantly different (median hs-CRP 2.20 vs 2.00 mg/L, interquartile range 0.40-6.54 vs 0.50-5.70, P = .36). In subgroup analysis, neither baseline testosterone level, nor age, nor baseline CRP-level modified the effect of testosterone supplementation on CRP levels.

Oral testosterone undecanoate supplementation, in dosage of 160 mg daily for 26 weeks, does not increase hs-CRP levels in elderly men.