Testosterone Gel (AndroGel, Testim): Application, Absorption & Comparison
Testosterone gels offer a needle-free alternative to testosterone injections for hormone replacement therapy. This comprehensive guide covers application techniques, transdermal absorption mechanisms, brand comparisons, advantages and disadvantages versus injections, and critical safety considerations including transfer risk to others.
What Is Testosterone Gel?
Testosterone gel is a topical formulation containing testosterone suspended in a hydroalcoholic base (typically ethanol and water plus stabilizers and permeation enhancers). The alcohol evaporates after application, allowing testosterone to penetrate the skin stratum corneum and diffuse into the dermis and subcutaneous tissue, where it enters systemic circulation through small blood vessels.
Testosterone gels are available in several formulations and brands, with AndroGel and Testim being the most widely prescribed. These pharmaceutical-grade products are FDA-approved for testosterone replacement therapy and are covered by most insurance plans when prescribed by physicians.
The primary advantage of testosterone gels is the needle-free application. Many patients prefer avoiding injections due to needle anxiety, skill requirements for self-injection, or convenience considerations. However, gels have distinct disadvantages compared to injections, including lower bioavailability, more variable absorption, greater cost, and transfer risk to household contacts.
Testosterone Gel Formulations and Brands
AndroGel is the most widely prescribed testosterone gel in the United States. Available in multiple formulations: the original 50mg/gram pump, newer AndroGel 1.62% (delivers 20.25mg per 1.25g dose from a metered-dose pump), and other strengths. The pump technology allows consistent dosing and convenient application.
Testim is another popular testosterone gel containing testosterone in a much more concentrated base (100mg per gram, or 50mg per 5g packet). Testim requires smaller application volumes than older AndroGel formulations, making it potentially less messy. However, Testim is less commonly prescribed and may have higher costs due to reduced generic competition.
Fortesta is a newer alternative delivering 40mg per metered dose from a pump, offering intermediate concentration. Less commonly prescribed than AndroGel or Testim due to higher cost and smaller patient base experience.
Axiron is a unique axillary (underarm) testosterone solution that absorbs transdermal through underarm tissue, supposedly minimizing transfer risk. Less commonly used due to lower absorption and convenience concerns compared to standard gels.
Compounded testosterone gels are prepared by compounding pharmacies and offer potential cost savings and customization options. However, quality control may vary compared to FDA-approved pharmaceutical-grade products. Compounded testosterone can be formulated in various base systems and concentrations depending on pharmacy capabilities and physician orders.
Transdermal Absorption and Bioavailability
Testosterone gel absorption occurs through the skin barrier via passive diffusion, facilitated by the alcohol base which disrupts the outermost skin layer (stratum corneum) and enhances permeation. The underlying hydroalcoholic formulation maintains a concentration gradient across the skin, driving continued testosterone diffusion until the gel is removed or evaporates.
Typical bioavailability of testosterone from gel is 20-50%, meaning that if 50mg of testosterone is applied, approximately 10-25mg actually enters systemic circulation. This is substantially lower than injectable testosterone, which has near 100% bioavailability. The lower bioavailability reflects the barrier function of intact skin, variable individual absorption rates, and incomplete application area coverage.
Absorption rate varies substantially by individual and application technique. Key factors influencing absorption include: skin hydration level (damp skin absorbs more; dry skin absorbs less), application site (thinner-skin areas absorb better), skin temperature (higher temperature increases absorption), body composition (leaner individuals may absorb slightly more), and individual genetic variation in skin barrier function.
Site-specific absorption varies predictably. Scrotal and facial skin have the highest absorption due to thin stratum corneum and high blood flow. Abdomen, upper arms, and shoulders have moderate absorption. Forearm has intermediate absorption. Lower leg and thick-skin areas have reduced absorption. Most patients apply testosterone gel to upper arms, shoulders, or abdomen for practical reasons rather than optimizing absorption.
Application-to-absorption timing typically shows peak serum testosterone levels 2-4 hours after application, though absorption begins immediately and continues for 24+ hours. Morning application provides peak levels in mid-morning to early afternoon, which somewhat mimics natural testosterone diurnal rhythm (though natural rhythm is much more pronounced).
Proper Application Technique
Testosterone gel should be applied to clean, dry skin for optimal absorption. Showering and drying skin thoroughly before application ensures the skin barrier is in optimal condition for absorption. Applying to damp skin reduces absorption, while applying to excessively dry skin (after prolonged time without moisture) may also reduce absorption slightly.
Application sites should be rotated daily to minimize local irritation and skin adaptation. Acceptable application sites include: upper arms, shoulders, abdomen (above the pubic line), and inner thighs. Scrotal application is no longer recommended despite superior absorption, as localized effects and transfer risk are problematic. Avoid sensitive areas, already-irritated skin, and areas with active acne or dermatitis.
For pump formulations, the pump must be primed before first use (typically 3-5 clicks into a sink or trash). After priming, each subsequent click delivers one metered dose. Standard dosing ranges from 4-10 clicks per day (equivalent to 50-100mg testosterone), with typical prescriptions at 75-100mg (5-7 clicks for most formulations).
Packet formulations require squeezing the entire contents onto skin and spreading over the application area. Packets are less convenient than pumps but ensure accurate dosing. Most patients using packets switch to pumps if available due to convenience.
Spreading testosterone gel evenly over a large area improves absorption. Lumping gel in one spot creates uneven absorption and increases local irritation risk. Using the palm of the opposite hand to spread gel over the application area optimizes distribution.
Allowing adequate absorption time before covering is crucial. Guidelines recommend waiting 2-6 hours before covering the application area with clothing or engaging in skin-to-skin contact. This allows the alcohol base to evaporate and testosterone to penetrate adequately. Showering should be delayed at least 2-6 hours post-application.
Hand hygiene is critical to prevent testosterone transfer to others. Wash hands thoroughly after application with soap and water. Some patients wear disposable gloves during application and disposal to eliminate transfer risk entirely.
Transfer Risk and Safety Precautions
Testosterone transfer to other people is a significant concern with testosterone gels. If skin-to-skin contact occurs within hours of application, substantial testosterone can transfer from application site to contact partner. Children and female partners are the most concerning populations for unintended testosterone exposure.
Women exposed to testosterone gel may develop virilization: deepening voice, increased body hair, clitoral enlargement, or acne. These changes may be irreversible, making prevention paramount. Several cases of virilized female partners and children have been documented from household testosterone gel exposure.
Children exposed to testosterone gel may develop accelerated puberty: genital enlargement, pubic hair development, voice changes, and behavioral effects. Some cases of severe unintended pediatric exposure have resulted in medical intervention and legal liability.
Transfer prevention strategies include: covering the application area with clothing, waiting 2-6 hours before direct skin contact, showering after application to remove surface residue, washing hands thoroughly immediately after application, using disposable gloves during application, and educating household members about transfer risk.
Some patients employ additional precautions like applying testosterone to areas easily covered with clothing or applying during times when close contact with partners/children is unlikely. Secure storage away from household members is essential to prevent accidental exposure.
Patients must disclose testosterone gel use to sexual partners and household members to ensure informed decision-making about exposure risk. Healthcare providers are obligated to counsel on transfer risk before prescribing testosterone gel.
Testosterone Gel Dosing and Serum Levels
Standard testosterone gel dosing ranges from 50-100mg daily for testosterone replacement therapy. Most patients achieve therapeutic testosterone levels (400-1000 ng/dL, typical target 500-700 ng/dL) with 75-100mg daily doses. However, substantial individual variation occurs—some patients achieve target levels at 50mg daily, while others require 100+ mg daily.
Serum testosterone levels achieved with testosterone gel are lower and more variable than injectable testosterone at equivalent nominal doses. For example, 75mg daily of testosterone gel might achieve 400-600 ng/dL serum levels in one patient and 250-400 ng/dL in another. This variability reflects individual differences in skin absorption and metabolism.
Time to steady-state serum levels with testosterone gel is typically 2-6 weeks. Early testing (before steady-state) will show lower levels than ultimate steady-state, potentially leading to incorrect dose adjustments. Most practitioners retest 6-8 weeks after starting gel to assess steady-state levels before making dose adjustments.
Diurnal testosterone rhythm is partially maintained with testosterone gel since absorption occurs throughout the day and is somewhat highest in morning/early afternoon (matching natural rhythm timing), though the rhythm amplitude is much blunted compared to natural levels.
Advantages of Testosterone Gel
Needle-free administration is the primary advantage. Many patients prefer topical application over injections due to needle anxiety, fear of infection, or general inconvenience with injection preparation and administration.
Non-surgical administration allows self-administration at home without requiring clinical visits. Patients can apply testosterone independently without medical supervision, making therapy convenient and discreet.
No injection-site complications. Avoiding intramuscular injections eliminates risks of infection, abscess formation, hematoma, or nerve damage. However, transdermal irritation is possible instead.
Daily dosing allows more frequent hormonal stimulation, which may produce more stable, physiologic testosterone levels compared to weekly injections. However, due to poor bioavailability, absolute serum levels are lower.
Disadvantages of Testosterone Gel
Lower bioavailability (20-50%) means that larger nominal doses are required to achieve equivalent serum testosterone levels compared to injections. A patient achieving 600 ng/dL on 75mg weekly testosterone cypionate injection might require 100-150mg daily testosterone gel to achieve equivalent levels.
More variable absorption and less stable serum levels result from individual variation in skin absorption and the variable nature of transdermal delivery. Some patients show 200+ ng/dL swings in testosterone levels within the day. This variability can make side effect management more difficult.
Higher cost compared to testosterone injections. Testosterone gel typically costs $50-200+ monthly without insurance, versus $50-100 monthly for testosterone injections. This cost difference is substantial long-term.
Skin irritation is common with testosterone gels. Localized redness, itching, erythema, and dermatitis occur in many users, particularly with frequent reapplication to the same sites. Site rotation and application breaks can minimize this, but some patients cannot tolerate gel due to skin reactivity.
Transfer risk to household members requires careful precautions and creates liability concerns. The need for constant vigilance about skin contact and transfer prevention is inconvenient and concerning for patients with children or partners.
Testosterone Gel vs. Injections: Direct Comparison
Serum testosterone levels are more stable and higher with injections. A 75mg weekly testosterone cypionate injection produces more stable and higher absolute levels than 100-150mg daily testosterone gel due to superior bioavailability and reduced absorption variability.
Cost favors injections substantially. Weekly injections at $50-100 monthly are cheaper than daily gel applications at $100-200 monthly, with cost difference more pronounced over years of therapy.
Convenience slightly favors gel (no syringes, needles, or appointment-based administration) but both are reasonably convenient for experienced users. Many patients comfortable with self-injection prefer injections despite gel being nominally "easier."
Side effect profile is similar between gel and injections since both deliver systemic testosterone, though the lower serum levels achieved with gel may reduce side effect magnitude slightly. However, the variable absorption of gel can make side effect management more difficult.
Transfer risk exists only with gel. This is a significant practical disadvantage for patients with children or female partners.
Most experienced TRT practitioners prefer testosterone injections due to superior pharmacokinetics, lower cost, and elimination of transfer risk. However, gel remains appropriate for patients with needle anxiety or strong preference for topical administration.
Side Effects and Monitoring
Skin irritation is the most common localized side effect. Erythema, itching, dermatitis, or contact dermatitis can develop at application sites. Site rotation, application breaks, and changing brand/formulation may resolve issues. For severe irritation, switching to injections may be necessary.
Systemic side effects are similar to injectable testosterone: water retention, acne, oily skin, mood changes, suppression of natural testosterone production, and potential cardiovascular effects. These generally occur at lower magnitude with gel due to lower achieved serum levels.
Blood work monitoring should include baseline assessment before starting testosterone, then 6-8 weeks into therapy to assess steady-state serum testosterone. Subsequent monitoring every 6-12 months is standard. Key metrics include total testosterone, free testosterone, estradiol, hematocrit, lipids, and liver enzymes.
Testosterone Gel Cost and Accessibility
With insurance, testosterone gel copays typically range from $10-50 monthly depending on coverage and formulation. Many insurance plans cover AndroGel or generic equivalents, though prior authorization may be required.
Without insurance, testosterone gel costs $100-200+ monthly depending on dose, brand, and pharmacy. Larger quantities or switching to compounded testosterone may reduce costs.
Prescription access requires a licensed healthcare provider and documented testosterone deficiency via blood work and clinical evaluation. Telemedicine providers increasingly offer testosterone gel prescriptions, making legal access more convenient.
Learn more about testosterone cypionate injections, TRT cost and coverage, and managing TRT side effects for related information.
Frequently Asked Questions
Testosterone gels contain testosterone suspended in a hydroalcoholic base that evaporates, allowing testosterone to penetrate the skin and absorb into the bloodstream through transdermal absorption. The alcohol base accelerates skin permeation. Once absorbed, testosterone enters systemic circulation and exerts androgenic and anabolic effects throughout the body.
AndroGel and Testim are both effective and similarly prescribed. Testim is slightly more concentrated (100mg per gram) versus AndroGel (50mg per gram for older formulations, 20mg/gram for newer Androgel 1.62%), meaning smaller volumes of Testim are needed. AndroGel may have slightly better skin tolerability. Choice often depends on insurance coverage and individual preference. Efficacy is comparable.
Testosterone gel effects appear more gradually than injections. Initial effects (mood, energy) may appear within 1-2 weeks. Measurable testosterone level increases appear within 2-4 weeks. Significant physical changes (muscle growth, strength) typically require 4-8 weeks or longer. Steady-state serum levels take 2-6 weeks to achieve depending on dose and application site.
Typical transdermal absorption of testosterone gel is 20-50% per application, meaning if you apply 50mg, approximately 10-25mg actually absorbs. Absorption varies based on: skin condition (dry vs. hydrated), application site, individual skin characteristics, and whether the area is washed before application. Damp skin increases absorption; dry skin decreases it. Consistent application technique optimizes absorption.
Apply testosterone gel to clean, dry skin on areas with good blood flow and relatively hairless surfaces: upper arms, shoulders, abdomen, or thighs. Wash hands after application to prevent transferring testosterone to others. Avoid showering or bathing for 2-6 hours after application to allow time for absorption. Applying to different sites daily helps prevent local skin irritation and optimizes absorption.
Yes, significant testosterone transfer can occur if the application site is not properly covered or dried. Skin-to-skin contact within hours of application can transfer testosterone to partners or children. Guidelines recommend covering the area with clothing and waiting 2-6 hours before direct skin contact. Female partners exposed to testosterone may develop virilization effects. Careful application technique and coverage are essential.
Testosterone gel costs vary widely. With insurance, copays typically range from $10-50 per month. Without insurance, costs range from $50-200+ per month depending on dose, brand, and pharmacy. Compounded testosterone may offer cost savings. Larger quantities purchased in advance can sometimes reduce per-dose costs. Generic versions of AndroGel are often cheaper than brand-name versions.
Testosterone gel offers convenience (no injections) but has drawbacks: lower and less stable serum levels due to skin barrier limitations, skin irritation potential, transfer risk to others, and higher costs. Injections provide more stable serum levels, higher bioavailability, and lower cost. Choice depends on individual priorities: convenience vs. stability and cost. Many practitioners prefer injections for these reasons.
Common side effects include skin irritation at application sites, potential acne or oily skin from systemic testosterone, water retention, mood changes, and suppression of natural testosterone production (like all testosterone therapy). Skin irritation is the most common localized side effect. Systemic side effects are similar to injectable testosterone but may be slightly less pronounced due to lower achieved serum levels with gels.
Testosterone gel has no ester and relies on skin depot, so it clears relatively quickly. Most testosterone is eliminated within 24 hours of the last application, though residual effects persist. Serum testosterone levels return to baseline within 2-7 days of discontinuation. Recovery of natural testosterone production takes weeks to months and requires post-cycle therapy similar to injections.