The bottom line is that there is no evidence that milk thistle is going to
help the OP. The OP has what is essentially a non-problem with no ill
effects on the liver.

That is pretty much a non-answer. Traditional use means that was the goal of
the treatment. It doesn't mean that it did squat. Traditional use of
bloodletting to supported George Washington's dirt nap. And supporting liver
health shows a total lack of understanding, considering that they had no
clue how the liver worked then. However, modern research tells a better
story:

   Milk thistle for the treatment of liver disease*1A systematic review and
meta-analysis
   The American Journal of Medicine, Volume 113, Issue 6, 15 October 2002,
Pages 506-515
   Bradly P. Jacobs MD, MPH, Cathi Dennehy PharmD, Gilbert Ramirez DrPH,
Jodi Sapp RN, and Valerie A. Lawrence MD, MSc.

   Abstract: PurposeMilk thistle, an herbal compound, is the dietary
supplement taken most frequently by patients with chronic liver disease. We
performed a systematic review of the literature to determine the efficacy
and safety of this herb for the treatment of liver disease.MethodsWe
searched English and non-English reports through July 1999 using thirteen
databases and reference lists, and contacting manufacturers and technical
experts. Reviewers independently screened all reports to identify randomized
placebo-controlled trials that evaluated milk thistle for the treatment of
liver disease. Outcomes of primary interest included mortality, histological
findings on liver biopsy specimens, serum aminotransferase and albumin
levels, and prothrombin times.ResultsFourteen trials met inclusion criteria.
Four trials reported outcomes for mortality among 433 participants. The
overall summary odds ratio for mortality in the milk thistle group compared
with placebo was 0.8 (95% confidence interval [CI]: 0.5 to 1.5; P = 0.6).
Three trials assessed histology on liver biopsy; study quality was inversely
associated with the likelihood of histological benefit for milk thistle
compared with placebo. There were no differences in serum alanine
aminotransferase, aspartate aminotransferase, or albumin levels, or
prothrombin times, among participants assigned to milk thistle compared with
those assigned to placebo. The only statistically significant difference was
a greater reduction in alanine aminotransferase levels among patients with
chronic liver disease assigned to milk thistle (?9 IU/L, 95% CI: ?18 to ?1
IU/L; P = 0.05), but this reduction was of negligible clinical importance
and no longer statistically significant after limiting analyses to studies
of longer duration or of higher quality. The frequency of adverse effects
was low and, in clinical trials, indistinguishable from
placebo.ConclusionTreatment with milk thistle appears to be safe and well
tolerated. We found no reduction in mortality, in improvements in histology
at liver biopsy, or in biochemical markers of liver function among patients
with chronic liver disease. Data are too limited to exclude a substantial
benefit or harm of milk thistle on mortality, and also to support
recommending this herbal compound for the treatment of liver disease.