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AndroGel Switching: Moving Between Testosterone Gel and Other TRT Formulations

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At a glance

  • Gel washout / After stopping AndroGel 1% at steady state, testosterone stays in the normal range for 24 to 48 hours and returns to pretreatment levels by the fifth day [2]
  • Switch study / 39 men entered; men on weekly subcutaneous enanthate received 50 or 100 mg after a topical washout [1]
  • Hematocrit by route / gel +3.0%, intramuscular enanthate or cypionate +4.0% versus placebo [3]
  • Gel versus injection, one retrospective chart review / hematocrit above 50% in 66.7% on injections versus 12.8% on gel [4]
  • Cardiovascular outcomes / TRAVERSE tested daily 1.62% gel: major adverse cardiovascular events 7.0% versus 7.3% [5]
  • Blood pressure / FDA said ambulatory studies confirmed a rise with all testosterone products, class-wide [6]

What the switching study measured

A phase II study enrolled 39 men with hypogonadism [1]. Men assigned to weekly subcutaneous testosterone enanthate were washed out of their topical testosterone regimens and given 50 or 100 mg weekly, while a reference group remained on 200 mg intramuscular enanthate [1]. Mean steady-state testosterone at week 6 was 422.4 ng/dL on 50 mg and 895.5 ng/dL on 100 mg [1].

The study measured blood levels and tolerability, not which switching schedule works better or how long a washout should last [1].

What happens to testosterone after the gel stops?

The AndroGel 1% label says that when treatment is discontinued after steady state is reached, serum testosterone concentrations remain in the normal range for 24 to 48 hours but return to their pretreatment concentrations by the fifth day after the last application [2].

Does hematocrit change with the formulation used?

A network meta-analysis of 29 placebo-controlled randomized trials (3,393 men) found gel raised mean hematocrit by 3.0% versus placebo and intramuscular enanthate or cypionate by 4.0% [3]. The trials were pooled by formulation; they did not measure hematocrit in the same man before and after a change of route [3].

A retrospective chart review of 178 hypogonadal men followed for 3 years found hematocrit above 50% in 66.7% of men on injectable testosterone versus 12.8% on gels and 35.1% on pellets [4]. The injection group was younger (mean 42.5 versus about 54 years) with higher baseline hematocrit, and the study was not randomized [4].

Blood pressure and cardiovascular checks

FDA said ambulatory blood pressure studies confirmed an increase in blood pressure with all testosterone products, class-wide, and in February 2025 required a new blood pressure warning for products that lacked one [6]. TRAVERSE, which tested daily 1.62% testosterone gel, found major adverse cardiovascular events in 7.0% of men on gel and 7.3% on placebo (hazard ratio 0.96, 95% CI 0.78 to 1.17) [5]. No outcome trial of that size has tested injectable testosterone [5].

Same drug, different gels

The AndroGel 1% label states that its dosage and administration differ from AndroGel 1.62%, and refers to the 1.62% prescribing information for that product [2]. The generic testosterone gel 1.62% label likewise says topical testosterone products may have different doses, strengths or application instructions that may result in different systemic exposure [7].

Frequently asked questions

What did the phase II switching study measure?
Thirty-nine men entered the study. Men assigned to weekly subcutaneous testosterone enanthate received 50 or 100 mg after a washout of topical testosterone, and mean steady-state testosterone at week 6 was 422.4 ng/dL on 50 mg and 895.5 ng/dL on 100 mg [1].
How fast does testosterone fall after stopping AndroGel?
The AndroGel 1% label says that after discontinuation at steady state, serum testosterone stays in the normal range for 24 to 48 hours and returns to pretreatment concentrations by the fifth day after the last application [2].
Does hematocrit change with the formulation used?
Both routes raise it. In a network meta-analysis of 29 placebo-controlled trials, intramuscular enanthate or cypionate raised mean hematocrit by 4.0% versus placebo and gel by 3.0% [3].
Does the TRAVERSE cardiovascular trial apply to injections?
TRAVERSE tested daily 1.62% testosterone gel, not injections. Major adverse cardiovascular events occurred in 7.0% on gel and 7.3% on placebo, hazard ratio 0.96 [5].
Do all testosterone products raise blood pressure?
FDA said ambulatory blood pressure studies confirmed an increase with all testosterone products, class-wide, and required a blood pressure warning for products that lacked one [6].

References

  1. Kaminetsky J, Jaffe JS, Swerdloff RS. Pharmacokinetic Profile of Subcutaneous Testosterone Enanthate Delivered via a Novel, Prefilled Single-Use Autoinjector: A Phase II Study. Sex Med. 2015;3(4):269-79. Pharmacokinetic Profile of Subcutaneous Testosterone Enanthate Delivered via a Novel, Prefilled Single-Use Autoinjector: A Phase II Study
  2. U.S. Food and Drug Administration, Drugs@FDA. AndroGel (testosterone gel) 1% prescribing information, NDA 021015, supplement 047, July 2025. AndroGel 1% prescribing information
  3. Nackeeran S, Kohn T, Gonzalez D, White J, Ory J, Ramasamy R. The Effect of Route of Testosterone on Changes in Hematocrit: A Systematic Review and Bayesian Network Meta-Analysis of Randomized Trials. J Urol. 2022;207(1):44-51. The Effect of Route of Testosterone on Changes in Hematocrit: A Systematic Review and Bayesian Network Meta-Analysis of Randomized Trials
  4. Pastuszak AW, Gomez LP, Scovell JM, Khera M, Lamb DJ, Lipshultz LI. Comparison of the Effects of Testosterone Gels, Injections, and Pellets on Serum Hormones, Erythrocytosis, Lipids, and Prostate-Specific Antigen. Sex Med. 2015;3(3):165-73. Comparison of the Effects of Testosterone Gels, Injections, and Pellets on Serum Hormones, Erythrocytosis, Lipids, and Prostate-Specific Antigen
  5. Lincoff AM, Bhasin S, Flevaris P, Mitchell LM, Basaria S, Boden WE, et al. Cardiovascular Safety of Testosterone-Replacement Therapy. N Engl J Med. 2023;389(2):107-117. Cardiovascular Safety of Testosterone-Replacement Therapy
  6. FDA issues class-wide labeling changes for testosterone products | FDA. FDA issues class-wide labeling changes for testosterone products | FDA
  7. U.S. National Library of Medicine, DailyMed. Testosterone gel 1.62% topical, generic (Padagis), the AndroGel 1.62% formulation type prescribing information. Testosterone gel 1.62% topical, generic (Padagis), the AndroGel 1.62% formulation type label
Evidence overview for AndroGel Switching: Moving Between Testosterone Gel and Other TRT Formulations