AndroGel Food & Supplement Interactions: What to Avoid and Why

Does food change how testosterone gel works?

Testosterone gel is applied to the skin and absorbed into the bloodstream. The drug interactions section of the generic testosterone gel 1% label has no food in it [1]. That tells you what the label lists; it does not show whether a particular food changes testosterone levels. The label also states that dosing for testosterone gel 1% differs from testosterone gel 1.62%, which has its own full prescribing information [1].

The interactions the label does list

The generic testosterone gel 1% label names three [1].

Insulin. Androgens may lower blood glucose and therefore lower insulin requirements in diabetic patients [1].

Oral anticoagulants. Changes in anticoagulant activity may be seen with androgens, so the label recommends more frequent monitoring of INR and prothrombin time, especially at the initiation and termination of androgen therapy [1].

Corticosteroids or ACTH. Used with testosterone, these may increase fluid retention, and the label says this requires careful monitoring, particularly in patients with cardiac, renal or hepatic disease [1].

Grapefruit, caffeine, dairy, high-fat meals and alcohol do not appear in the label's interactions section [1]. The findings below show what each substance does on its own, not how it changes gel treatment.

Alcohol

A review of alcohol's effects on male reproduction reports that heavy alcohol consumption results in reduced testosterone levels in the blood, with interference at three levels: the hypothalamus, the pituitary, which releases LH and FSH, and the testes, including the Leydig cells that produce testosterone [5].

Zinc

Moderate to severe zinc deficiency is associated with hypogonadism in men [6]. In one experiment, four young men on a zinc-restricted diet for 20 weeks had mean serum testosterone fall from 39.9 to 10.6 nmol/L [6]. In a second group, nine older men with marginal zinc deficiency took oral zinc gluconate, 459 micromoles of zinc a day (about 30 mg), and after six months mean testosterone rose from 8.3 to 16.0 nmol/L [6]. Both groups were very small [6].

Magnesium

In a four-week study, men given magnesium at 10 mg per kg of body weight had higher free and total plasma testosterone after supplementation, both in sedentary men and in tae kwon do athletes, measured at rest and after exhaustion; the increases were larger in the men who exercised [7].

Vitamin D

In a cross-sectional survey of 3,369 men aged 40 to 79, vitamin D deficiency was associated with secondary hypogonadism (relative risk ratio 1.16) and compensated hypogonadism (1.52), but after adjustment for health and lifestyle factors there was no significant association between 25-hydroxyvitamin D and individual reproductive hormones [12].

A randomized trial looked at this more directly. Of 54 overweight men in a weight-reduction program who completed the trial, all with vitamin D in the deficiency range at baseline, those given 3,332 IU of vitamin D a day for a year (31 men) had total testosterone rise from 10.7 to 13.4 nmol/L, while testosterone did not change significantly on placebo [13].

Ashwagandha

In a 16-week randomized, double-blind, crossover trial, overweight men aged 40 to 70 with mild fatigue took a standardized ashwagandha extract, 21 mg of withanolide glycosides a day, or placebo for 8 weeks. Fifty-seven men were enrolled and 43 completed all 16 weeks [8]. Salivary testosterone rose 14.7% more than with placebo (p=0.010) and DHEA-S rose 18% more (p=0.005), with no significant between-group differences in cortisol, estradiol, fatigue, vigor or sexual well-being [8].

Soy and isoflavones

A meta-analysis of 15 placebo-controlled treatment groups found no significant effect of soy protein or of soy or red clover isoflavones on total testosterone, free testosterone, sex hormone-binding globulin or free androgen index in men [9].

Testosterone boosters, pre-workout and protein powders

A review of pre-workout, fat-burner, cognitive-booster and testosterone-booster supplements found that many food supplements have been contaminated with unauthorized substances, that some ingredients were medicinal products or new synthetic compounds added without clinical trials, and that some ingredients are prohibited in sport [2].

One analyzed supplement contained 19-nor-4-androstene-3,17-dione and 4-androstene-3,17-dione. A single capsule given to five male volunteers produced urine norandrosterone, the main nandrolone metabolite, above 2 ng/mL until 48 to 144 hours after ingestion [3]. A separate review notes that some protein supplements intended for athletes may be adulterated with anabolic steroids and prohormones, which can produce a positive anti-doping test [4]. In WADA-governed sport, testosterone is prohibited at all times regardless of a prescription, and a Therapeutic Use Exemption is required [14].