Testosterone Gel vs Injections: Levels, Side Effects and Practicalities
Gels and injections deliver the same hormone, but they behave very differently day to day. One is a daily application with a transfer risk to the people you live with; the other is a periodic shot with bigger swings in blood levels and a higher rate of raised hematocrit. This guide sets out what the prescribing labels and studies actually say about each.
- Gels are applied once a day to the shoulders and upper arms and give steadier levels; injections of cypionate or enanthate rise above the normal range after the shot and fall toward the low range by the end of the interval.
- The AndroGel and Testim labels carry a boxed warning: children have been virilized by secondary exposure. Washing hands, letting the gel dry and covering the site with a T-shirt are the label's defences.
- Raised hematocrit is more common with injections. In one 3-year clinic cohort, hematocrit above 50% occurred in 66.7% of men on injections versus 12.8% on gels, though the groups were not matched.
- The largest cardiovascular safety trial of testosterone, TRAVERSE, used 1.62% gel. Real-world persistence with gels is low: in one claims analysis only 15.4% were still filling prescriptions at 12 months.
Short answer: testosterone gel gives steadier day-to-day levels and less erythrocytosis, while injections of testosterone cypionate or enanthate produce peaks and troughs across the dosing interval and raise hematocrit more often4,6. Gels have a unique risk of their own: testosterone can transfer to children and partners through skin contact, which is the subject of a boxed warning on the gel labels1,2. Injections avoid transfer but need a needle and regular injections. Neither is "stronger"; both are dosed to the same blood testosterone targets.
This guide compares the two on what the labels and published studies show. It does not cover which is right for you; that depends on your labs, health history and preferences, and it is a decision to make with your prescriber. Prices are left out because they vary too much by country, insurer and pharmacy to be useful.
Gel vs injection at a glance
| Testosterone gel (e.g. AndroGel 1.62%, Testim 1%) | Injectable cypionate or enanthate | |
|---|---|---|
| How often | Once daily1,2 | Label for cypionate: 50–400 mg every 2–4 weeks3; many prescribers split doses more often |
| Where | Shoulders and upper arms1,2 | Label for cypionate: gluteal muscle3; other IM and SubQ sites used in practice |
| Level pattern | Less fluctuation than cypionate or enanthate4 | Rises above normal after the shot, falls toward the low range by the end of the interval4 |
| Erythrocytosis | Less than injectable testosterone4 | Highest incidence with short-acting injectables6 |
| Unique risk | Secondary exposure of children and women (boxed warning)1,2 | Needle handling; injection-site reactions |
| First lab check | Morning, pre-dose, ~14 days after starting1,2 | Mid-interval, several weeks in (see our bloodwork guide) |
| When stopped | Levels back near baseline within 48–72 hours (AndroGel 1.62%)1 | Depends on the ester; see ester half-lives |
How gels are dosed and applied
AndroGel 1.62% starts at 40.5 mg of testosterone a day (two pump actuations or one packet), applied to clean, dry, intact skin of the shoulders and upper arms. The dose is adjusted between 20.25 mg and 81 mg based on morning pre-dose testosterone measured at about 14 and 28 days, aiming for 350–750 ng/dL1. The label lists places not to apply it: abdomen, genitals, chest, armpits and knees. Patients are told to wait at least 2 hours before showering or swimming, wash their hands with soap and water, and cover the site with clothing once it is dry1.
Testim 1% starts at 50 mg (one tube) daily, preferably in the morning, to the shoulders and/or upper arms, within the area a short-sleeved T-shirt would cover. If morning pre-dose testosterone at about 14 days is below 300 ng/dL, the dose can go up to 100 mg, which is the maximum2. According to the label, about 10% of the testosterone applied is absorbed over 24 hours, and the skin acts as a reservoir that keeps releasing it through the day2.
Two practical points from the labels matter more than they look. First, gels are not interchangeable: the Testim label states that it is not substitutable with other topical testosterone products, and AndroGel 1.62% is dosed differently from AndroGel 1%1,2. A switch between brands is a new prescription with new labs, not a one-for-one swap. Second, the alcohol-based gels are flammable until dry, so the labels warn against fire, flame and smoking during application1,2.
How injections are dosed
The Depo-Testosterone (cypionate) label gives 50–400 mg every two to four weeks for male hypogonadism, by intramuscular injection into the gluteal muscle3. The drug is dissolved in cottonseed oil with benzyl benzoate and benzyl alcohol3. In practice many prescribers use smaller, more frequent doses to reduce peaks and troughs, and some use subcutaneous injection; the SubQ vs IM guide and the microdosing guide cover those protocols. Unlike the gels, the cypionate label has no boxed warning3.
The Endocrine Society's guideline lists the trade-offs plainly. Injections allow flexible dosing, but they require an injection and cause peaks and valleys in serum testosterone that may be felt as symptoms change across the interval. Gels allow flexible dosing and are easy to apply, with good skin tolerance and less erythrocytosis than injectable testosterone, but carry the potential for transfer and testosterone levels can vary from one application to the next4.
Blood levels: steady vs peaks and troughs
The guideline describes the injectable pattern as a rise into the supraphysiological range after a single IM injection, followed by a gradual decline into the hypogonadal range by the end of the dosing interval4. Gels, at the right dose, bring testosterone and estradiol into the normal male range with less fluctuation4.
The labels show how that looks in trials. In the AndroGel 1.62% study, 81.6% of patients (146 of 179) had an average 24-hour testosterone concentration in the normal range of 300–1000 ng/dL at day 112, and 78% (106 of 136) of those treated for a year were still in range at day 3641. Peaks are not absent with gel: at day 112, 11.2% had a peak above 1500 ng/dL1. With Testim, the average daily concentration after 30 days was 365 ng/dL on 50 mg and 612 ng/dL on 100 mg2, which shows why the dose is adjusted by labs rather than fixed.
One consequence for bloodwork: on gel, the labels time the check as a morning, pre-dose draw; on injections, where in the interval you draw changes the number a lot. Our TRT bloodwork guide covers timing for each.
Hematocrit and erythrocytosis
All forms of testosterone raise hemoglobin and hematocrit. A meta-analysis of 51 studies found an average hematocrit increase of 3.18 percentage points on testosterone compared with controls10. What differs is how often it goes too far. A review of testosterone-induced erythrocytosis concludes that short-acting injectable testosterone carries a greater risk than other formulations6, and the Endocrine Society guideline lists less erythrocytosis as an advantage of gels4.
The most-cited comparison is a retrospective clinic cohort followed for 3 years. Hematocrit above 50% occurred in 66.7% of men on injectable testosterone, 35.1% on pellets and 12.8% on gels5. Read that with its limits: the injection group was younger (average 42.5 vs 54.1 years for gels) and started with higher hemoglobin and hematocrit, and there were only 47 men on gel and 57 on injections5. The direction matches the guideline; the size of the gap should not be treated as exact.
The gel labels report low rates in their own trials. AndroGel 1.62% lists increased hematocrit or hemoglobin in 2.1% of treated patients versus 0% on placebo over 182 days1. For Testim, in the combined U.S. and European trials, 2.8% of patients on 100 mg had hematocrit of 58% or more, compared with 1.5% on placebo2. Both labels tell prescribers to check hematocrit before starting, with the AndroGel label adding a recheck at 3 to 6 months and then yearly, and to stop therapy until it falls if it becomes elevated1. For what the thresholds mean and how prescribers respond, see high hematocrit on TRT.
Secondary exposure: the gel-specific risk
The boxed warning on testosterone gels exists because children have been virilized by contact with a parent's application site. The labels describe enlargement of the penis or clitoris, pubic hair, increased erections and libido, aggressive behaviour and advanced bone age. In most cases these regressed when exposure stopped, but in a few cases genitalia did not fully return to normal size and bone age stayed ahead of chronological age1,2. Adult women exposed to gel may notice changes in body hair or a marked increase in acne1. In at least one reported case, exposure was thought to come from shirts, towels or sheets1.
The transfer studies show why the label insists on covering up. When women rubbed a man's shoulders and upper arms 2 hours after he applied AndroGel 1.62% 81 mg, their average testosterone exposure rose by 280%; when the site was covered by a T-shirt, the increase was 6%1. A published analysis of three such studies concluded that the risk of transfer lasts at least 12 hours after application and that a T-shirt barrier reduces it7.
- Apply only to the label sites (shoulders and upper arms), not the abdomen or chest1,2.
- Wash your hands with soap and water right after applying1,2.
- Let the gel dry, then cover the area with clothing1,2.
- Wash the site with soap and water before any skin-to-skin contact you expect2.
- Tell your prescriber about signs of virilization in a child or partner; the gel should be stopped until the cause is found1.
Other side effects compared
Most side effects follow testosterone itself, not the delivery route. The gel labels list PSA increases, blood pressure increases and mood changes, and the AndroGel 1.62% trial reported increased PSA in 11.1% of patients versus 0% on placebo, the most common reason for stopping1. Skin reactions are the gel-specific one, and they were uncommon: 0.9% of AndroGel 1.62% patients in the double-blind period1, and 2–4% on Testim compared with 3% on placebo gel2. Injections bring their own local issues, such as soreness, bruising and occasional lumps; the injection guide covers those.
On cardiovascular risk, the best data come from a gel. The TRAVERSE trial randomised 5,246 men aged 45 to 80 with hypogonadism and existing or high cardiovascular risk to daily 1.62% gel or placebo gel, adjusted to keep testosterone between 350 and 750 ng/dL. Major cardiac events occurred in 7.0% on testosterone and 7.3% on placebo, meeting the test for non-inferiority, while atrial fibrillation, acute kidney injury and pulmonary embolism were more common with testosterone9. Because TRAVERSE used gel, its reassurance applies most directly to gel at those levels; there is no trial of the same size for injections.
Adherence and daily practicalities
A daily routine is easy to start and easy to drop. In a claims analysis of 15,435 men starting testosterone gel in 2009, only 34.7% were still on it at 6 months and 15.4% at 12 months, with similar rates for AndroGel and Testim and across age groups; about half of those who stopped later restarted8. Claims data cannot say why people stopped, but it is a useful reality check on "just apply it every morning".
| Practical factor | Gel | Injection |
|---|---|---|
| Needles | None | Needle and syringe each dose; sharps disposal |
| Time per dose | Apply, dry, wash hands, dress1,2 | Draw, inject, rotate sites |
| Showering and swimming | Wait at least 2 hours after AndroGel 1.62%1 | No restriction |
| Household contact | Cover and wash before skin contact1,2 | No transfer risk from the dose itself |
| Missed dose effect | Levels fall within days; near baseline 48–72 h after stopping AndroGel 1.62%1 | Levels decline gradually through the dosing interval4 |
| Switching brands | Not substitutable; relabelled dosing1,2 | Cypionate and enanthate are close; see our comparison |
Switching between gel and injections
There is no fixed conversion between a daily gel dose and a weekly injection, because only a fraction of gel is absorbed and absorption varies between people and products2,4. Prescribers who switch someone usually pick a starting injection dose, then adjust it on labs, drawn at the right point in the interval. The same goes the other way, with the morning pre-dose draw at around two weeks that the gel labels describe1,2. Recheck hematocrit after the switch, especially when moving from gel to injections4,6.
If you are tracking a switch, write down the date, dose and route, and keep your lab results next to them. Peptide Me lets you log any prescribed medication next to your bloodwork and chart testosterone and hematocrit over time, so the number most likely to change when you move to injections is on the same timeline as the switch.
Disclaimer: this guide summarises prescribing information and published research and is not medical advice. Testosterone is a prescription, controlled medication. The formulation, dose and monitoring schedule are decisions for you and your prescriber.
FAQ
References
Primary sources — PubMed / NEJM / The Lancet.
- DailyMed. ANDROGEL (testosterone) gel 1.62%, for topical use, CIII — Prescribing Information. Revised October 2025. U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f4e8d29b-8707-4d47-e053-2a95a90aecee
- DailyMed. TESTIM (testosterone gel) 1%, for topical use, CIII — Prescribing Information. Endo USA, Inc. Revised July 2025. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9f2aae1f-898d-4955-be31-678e0cf85395
- DailyMed. DEPO-TESTOSTERONE (testosterone cypionate) injection, solution — Prescribing Information. U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=cfbb53d4-b868-4a28-8436-f9112eb01c39
- Bhasin S, Brito JP, Cunningham GR, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715-1744. https://academic.oup.com/jcem/article/103/5/1715/4939465
- 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):165-173. https://pmc.ncbi.nlm.nih.gov/articles/PMC4599554/
- Ohlander SJ, Varghese B, Pastuszak AW. Erythrocytosis Following Testosterone Therapy. Sex Med Rev. 2018;6(1):77-85. https://pmc.ncbi.nlm.nih.gov/articles/PMC5690890/
- Stahlman J, Britto M, Fitzpatrick S, et al. Serum testosterone levels in non-dosed females after secondary exposure to 1.62% testosterone gel: effects of clothing barrier on testosterone absorption. Curr Med Res Opin. 2012;28(2):291-301. https://pubmed.ncbi.nlm.nih.gov/22188558/
- Schoenfeld MJ, Shortridge E, Cui Z, Muram D. Medication adherence and treatment patterns for hypogonadal patients treated with topical testosterone therapy: a retrospective medical claims analysis. J Sex Med. 2013;10(5):1401-1409. https://pubmed.ncbi.nlm.nih.gov/23464534/
- Lincoff AM, Bhasin S, Flevaris P, et al. Cardiovascular Safety of Testosterone-Replacement Therapy (TRAVERSE). N Engl J Med. 2023;389(2):107-117. https://pubmed.ncbi.nlm.nih.gov/37326322/
- Fernández-Balsells MM, Murad MH, Lane M, et al. Adverse effects of testosterone therapy in adult men: a systematic review and meta-analysis. J Clin Endocrinol Metab. 2010;95(6):2560-2575. https://pubmed.ncbi.nlm.nih.gov/20525906/