AndroGel Variable Absorption: Diet Protocols That Help Stabilize Testosterone Levels

What the diet studies measure

The diet studies below tracked blood testosterone in men eating different diets. None of those men was applying a testosterone gel, so the numbers describe diet effects on measured testosterone, not on how much testosterone crosses the skin from a gel.

In a study of a 1% testosterone gel, doses were adjusted after 90 days when pre-application serum testosterone was outside the normal adult male range; the study did not test diet as a way to adjust absorption [8].

Fat, fiber and testosterone

In a crossover feeding study, 43 healthy men ate a diet with 41.0% of energy from fat (and less fiber) for 10 weeks and one with 18.8% from fat (and more fiber) for 10 weeks. Total testosterone was 13% higher and SHBG-bound testosterone 15% higher on the high-fat, low-fiber diet; the difference was statistically significant only for the SHBG-bound fraction (P=0.04) [1].

Going the other way, 39 men aged 50 to 60 switched from their usual diet to an isocaloric low-fat, high-fiber diet for eight weeks. Mean serum testosterone fell, and the authors summarized a 12% lowering of circulating androgen levels with no change in testosterone clearance [2]. A meta-analysis of six intervention studies with 206 participants found that low-fat diets lowered total testosterone (standardized mean difference -0.38, 95% CI -0.75 to -0.01) and free testosterone [3].

Zinc, vitamin D, soy and alcohol

Twenty weeks of dietary zinc restriction in four healthy young men was associated with a fall in serum testosterone from 39.9 to 10.6 nmol/L [4]. In the same report, nine older men with marginal zinc deficiency who took oral zinc gluconate for three to six months saw testosterone rise from 8.3 to 16.0 nmol/L [4].

Among 54 overweight men in a weight reduction program who completed a year-long randomized trial, 31 took 3,332 IU of vitamin D daily. Their average total testosterone rose from 10.7 to 13.4 nmol/L, while the 23 men on placebo had no significant change [5].

A meta-analysis of soy protein and isoflavone studies found no significant effect on total testosterone, SHBG, free testosterone or free androgen index in men [6].

In 16 men given alcohol acutely, plasma testosterone fell as blood alcohol rose and stayed depressed at a peak blood alcohol of about 109 mg/100 mL [7].