AndroGel vs Jatenzo: Switching Between Them

What Are AndroGel and Jatenzo?

AndroGel is a hydroalcoholic testosterone gel applied once daily to the shoulders, upper arms, or abdomen. Jatenzo is an oral testosterone undecanoate capsule taken twice daily with food. Both are FDA-approved treatments for hypogonadism in adult men who have low testosterone due to a medical condition, not solely age-related decline. Despite treating the same condition, their mechanisms of absorption, their safety profiles, and the practical demands they place on patients differ in ways that matter when choosing between them or switching.

AndroGel: Mechanism and Approved Doses

AndroGel 1% delivers 50 mg testosterone per 5 g packet or pump actuation. AndroGel 1.62% delivers 20.25 mg per pump actuation, with a starting dose of two actuations (40.5 mg) daily. The gel dries quickly and testosterone absorbs transdermally over 24 hours, producing relatively stable serum levels without the sharp peaks seen with injections. The FDA label for AndroGel 1.62% is available at accessdata.fda.gov [1].

Skin-to-skin transfer to women or children is a documented risk. The FDA added a black-box warning about secondary exposure in 2009 [1]. Men who share a bed with a partner or have young children at home should apply gel to covered areas and wash hands immediately.

Jatenzo: Mechanism and Approved Doses

Jatenzo (testosterone undecanoate) is absorbed via intestinal lymphatic transport, bypassing first-pass hepatic metabolism. This is the same mechanism used by Andriol in Europe, though Andriol and Jatenzo are not interchangeable products. The approved starting dose is 237 mg twice daily with food; after 90 days, the prescriber adjusts to 158 mg, 237 mg, or 316 mg twice daily based on serum testosterone measured 6 hours post-dose. The full Jatenzo prescribing information is at accessdata.fda.gov [2].

Because Jatenzo relies on dietary fat for lymphatic uptake, skipping a meal significantly reduces absorption. A low-fat or skipped meal can cut peak testosterone levels by roughly 50% compared with a full meal [2].

How Well Does Each Drug Work?

Both formulations raise serum testosterone into the normal adult male range (300 to 1,000 ng/dL per most laboratory reference intervals), but the evidence base behind each is different in size and design.

Evidence for AndroGel

The Testosterone Trials (T-Trials), a coordinated set of seven placebo-controlled trials in 788 men aged 65 or older with low testosterone (<275 ng/dL), used transdermal testosterone gel and demonstrated normalization of serum testosterone across multiple outcome domains [3]. Published in the New England Journal of Medicine in 2016, the sexual function trial showed that testosterone treatment improved sexual activity scores significantly vs. Placebo (P<0.001) [3]. The T-Trials used AndroGel 1% titrated to maintain mid-normal serum levels (500 to 800 ng/dL target), providing the most strong clinical outcomes data for any transdermal TRT formulation currently available.

Earlier dose-finding work confirmed that 50 mg/day AndroGel 1% raised mean serum testosterone from roughly 235 ng/dL at baseline to approximately 555 ng/dL at steady state [4]. That finding, published in the Journal of Clinical Endocrinology and Metabolism, established the pharmacokinetic profile that underpins current dosing guidance [4].

Evidence for Jatenzo

Swerdloff et al. (2020) conducted the key Phase 3 trial of Jatenzo in 166 hypogonadal men over 90 days [5]. Eighty-seven percent of participants achieved a mean serum testosterone within the normal range (300 to 1,000 ng/dL) during the primary efficacy window. The study also reported a mean increase in diastolic blood pressure of 3.1 mmHg from baseline, a finding that prompted the FDA's blood-pressure black-box warning on the product label [5]. The trial is available at pubmed.ncbi.nlm.nih.gov [5].

A subsequent pooled analysis of Jatenzo safety data submitted to the FDA noted that blood pressure elevations were generally modest and reversible with dose adjustment or discontinuation, but men with pre-existing hypertension saw larger increases than normotensive men [2].

Side-Effect Profiles: Where They Differ

AndroGel-Specific Risks

The dominant AndroGel-specific risks are skin-to-skin testosterone transfer and application-site reactions (erythema, dryness in roughly 4 to 9% of users) [1]. Polycythemia (hematocrit above 54%) is a class effect of all testosterone therapies; the Endocrine Society clinical practice guideline recommends checking hematocrit at baseline and at 3 and 6 months, then annually [6]. The 2018 Endocrine Society guideline states: "We suggest checking hematocrit before starting testosterone therapy, at 3 to 6 months, and then annually" [6].

Jatenzo-Specific Risks

Blood pressure elevation is the most clinically distinct risk with Jatenzo. The FDA black-box warning specifies that Jatenzo may increase blood pressure and can raise the risk of major adverse cardiovascular events [2]. Prescribers are advised to measure blood pressure before initiating therapy, at 3 months, and then in accordance with clinical practice guidelines for hypertension. Men with a baseline systolic blood pressure above 160 mmHg are generally not considered appropriate candidates without antihypertensive optimization first.

Jatenzo also causes gastrointestinal side effects (nausea, diarrhea) in roughly 5 to 7% of users, particularly during the first few weeks [5]. This is less common with AndroGel.

Shared Risks

Both drugs suppress the hypothalamic-pituitary-gonadal axis, reducing LH and FSH and impairing spermatogenesis. Both can accelerate erythropoiesis. Neither is appropriate for men who wish to preserve fertility without adjunctive therapy (e.g., human chorionic gonadotropin). The FDA TRT class label summarizes these shared risks at accessdata.fda.gov [2].

Cardiovascular risk from TRT remains an active research area. The TRAVERSE trial (N=5,246), published in the New England Journal of Medicine in 2023, found that testosterone replacement was non-inferior to placebo for major adverse cardiovascular events in men with hypogonadism and pre-existing or high-risk cardiovascular disease, with a hazard ratio of 0.96 (95% CI 0.78 to 1.17) [7]. That finding applies to the TRT class broadly, not to Jatenzo specifically, and does not negate the blood-pressure signal specific to Jatenzo [7].

Pharmacokinetics: Peaks, Troughs, and Stability

AndroGel Kinetics

AndroGel produces a gradual rise in serum testosterone over 4 to 8 hours after application, reaching steady state within 24 to 48 hours of consistent daily use [4]. Levels are relatively flat across the day, which is clinically useful for men who are sensitive to mood or energy fluctuations tied to testosterone peaks. Serum levels should be measured 2 to 8 hours after application to capture the meaningful mid-point of the daily curve [1].

Jatenzo Kinetics

Jatenzo produces two daily peaks, roughly 4 to 6 hours after each dose, because it is taken twice daily. This creates a different serum profile: higher peaks relative to trough, but two cycles per day rather than one. The FDA-specified monitoring window is 6 hours post-morning-dose at the 90-day titration visit [2]. Patients and providers should be aware that a blood draw outside this window will produce a misleading result and lead to incorrect dose adjustments.

A useful benchmark: in the Swerdloff 2020 trial, the mean Cavg (average concentration) at steady state was approximately 428 ng/dL at the 237 mg twice-daily starting dose, rising to a mean Cmax of roughly 936 ng/dL at peak [5]. Both values fall within the normal adult male reference range for most labs.

Who Should Consider Switching, and Why?

Switching between AndroGel and Jatenzo is most often initiated for one of four reasons: intolerable side effects, insufficient testosterone response after dose optimization, patient preference (lifestyle or convenience), or a new clinical finding that makes the current formulation less appropriate.

The table below outlines the most common clinical scenarios driving a switch in either direction.

| Clinical Scenario | Direction | Rationale | |---|---|---| | Skin transfer risk (young children, pregnant partner) | AndroGel → Jatenzo | Eliminates secondary exposure risk entirely | | New diagnosis of uncontrolled hypertension | Jatenzo → AndroGel | AndroGel carries no BP black-box warning | | Subtherapeutic T on AndroGel despite 81 mg/day | AndroGel → Jatenzo | Poor transdermal absorption in some patients | | GI intolerance to Jatenzo | Jatenzo → AndroGel | Once-daily gel eliminates twice-daily food requirement | | Occupational exposure concern (patient is a wrestler, physical therapist) | Any gel → Jatenzo | Eliminates occupational transfer liability | | Patient forgets twice-daily dosing | Jatenzo → AndroGel | Once-daily application simplifies adherence |

Poor transdermal absorption is a real and underappreciated reason for switching away from AndroGel. Skin thickness, body fat percentage, and sweat rate all affect gel absorption. A 2011 study in the Journal of Clinical Endocrinology and Metabolism found that absorption efficiency varied nearly 3-fold among men using the same AndroGel dose [4], explaining why some men remain below 300 ng/dL despite maximal topical dosing.

How to Switch From AndroGel to Jatenzo

Switching from AndroGel to Jatenzo does not require a washout period. The steps below reflect current prescribing information from both manufacturers and standard clinical practice.

Step-by-Step Protocol

1. Apply the last dose of AndroGel in the morning as usual.
2. Start Jatenzo 237 mg twice daily that same evening with dinner. Beginning with dinner on the day of the last gel application avoids a gap in serum testosterone levels.
3. Schedule a blood draw at week 4 (not the mandated 90-day titration draw) to confirm that levels are within range during the transition period. The 90-day titration draw will follow per label.
4. Measure blood pressure at the week-4 visit. If systolic blood pressure has risen by more than 10 mmHg from pre-switch baseline, assess antihypertensive options before continuing Jatenzo [2].
5. Check hematocrit at the 3-month mark per the Endocrine Society guideline, as the class effect on erythropoiesis is maintained regardless of formulation [6].

The Endocrine Society 2018 clinical practice guideline on testosterone therapy in men states: "We recommend measuring testosterone levels to ensure levels are in the mid-normal range" at appropriate follow-up intervals [6]. The same principle applies during any formulation switch.

How to Switch From Jatenzo to AndroGel

Switching from Jatenzo to AndroGel is equally straightforward but requires attention to the timing of the monitoring blood draw.

Step-by-Step Protocol

1. Take the last Jatenzo dose in the evening.
2. Apply the first AndroGel dose (start at the standard 40.5 mg/day for 1.62%, or 50 mg/day for 1%) the following morning.
3. Draw serum testosterone 2 to 8 hours after the AndroGel application at week 4. Do not draw before the gel has been on for at least 2 hours.
4. If testosterone remains below 400 ng/dL at week 4, up-titrate per the AndroGel label (maximum 81 mg/day for 1.62%) [1].
5. Measure blood pressure at week 4 to confirm it has stabilized or improved following the discontinuation of Jatenzo.

Men switching because of hypertension concerns may notice blood pressure improvement within 2 to 4 weeks of stopping Jatenzo, consistent with the reversibility observed in the Swerdloff trial's open-label extension data [5].

Monitoring Parameters After Any Switch

Regardless of direction, the following monitoring schedule applies after switching TRT formulations.

Labs and Timing

• Total testosterone: at 4 weeks (transition confirmation) and 3 months (formal titration)
• Hematocrit: at 3 months and 6 months, then annually [6]
• PSA: at 3 to 6 months post-initiation or post-switch in men aged 40 or older with a baseline PSA above 0.6 ng/mL, per the Endocrine Society guideline [6]
• Comprehensive metabolic panel: no mandatory schedule, but clinically prudent at 3 months given that Jatenzo undergoes lymphatic rather than hepatic absorption and liver enzyme monitoring is generally low-yield with either formulation

Blood Pressure Monitoring

For Jatenzo specifically, blood pressure must be measured before starting, at 3 to 4 weeks, and at 3 months [2]. For AndroGel, blood pressure monitoring follows standard cardiovascular risk management, not a product-specific schedule. The TRAVERSE trial data suggest clinicians should monitor blood pressure in all TRT patients, regardless of formulation, at least every 6 months [7].

A 2023 NEJM editorial accompanying the TRAVERSE results noted that the cardiovascular safety data "should be interpreted in the context of the specific population studied" and should not be generalized to younger men or to formulations with distinct pharmacokinetic profiles [7].

Cost, Insurance, and Practical Access

AndroGel 1.62% carries a list price of roughly $500, $600 per month without insurance. Generic testosterone gel 1% (available since 2015) costs $40, $80 per month at most pharmacies and offers comparable efficacy to branded AndroGel at equivalent doses [1]. Jatenzo has no current generic equivalent; its list price is approximately $600, $700 per month, and prior authorization requirements are common because oral testosterone is still considered a newer formulation by most payers [2].

Medicare Part D coverage for both products varies by plan. Men on Medicare who switch should verify formulary status before the new prescription is written to avoid a coverage gap. The FDA maintains an up-to-date drug approval list at accessdata.fda.gov [8].