Short answer: Same hormone, different delivery. Cypionate is injected into muscle every 2 to 4 weeks and has a half-life of about 8 days.1 Gels such as AndroGel 1.62% and Testim are rubbed on daily and absorb over 24 hours.23 Gels carry a boxed warning about transfer to children; in one clinic review, high hematocrit was more common on injections.4
| Cypionate injection (Depo-Testosterone) | Testosterone gel (AndroGel 1.62%, Testim) | |
|---|---|---|
| Route | Injection into muscle1 | Rubbed onto the shoulders and upper arms; AndroGel 1.62% must not go on the abdomen, genitals, chest, armpits or knees2 |
| Approval status | FDA approved; Schedule III | FDA approved; Schedule III |
| Label dosing schedule | 50 to 400 mg every 2 to 4 weeks for male hypogonadism1 | AndroGel 1.62%: 40.5 mg once daily to start, adjusted between 20.25 and 81 mg2. Testim: 50 mg once daily to start, up to 100 mg3 |
| How long it lasts | Half-life about 8 days (label: approximately eight days)1 | Delivers testosterone over 24 hours after each application. After stopping AndroGel 1.62%, levels return to about baseline within 48 to 72 hours2 |
| Dose checks on the label | Not specified beyond periodic monitoring | AndroGel 1.62%: morning pre-dose testosterone at about 14 and 28 days, then periodically2 |
| Boxed warning | None | Secondary exposure: children have shown virilization after contact with the gel23 |
| Blood pressure | Can raise blood pressure; not recommended with uncontrolled hypertension1 | AndroGel 1.62%: +1.9/1.3 mm Hg after 16 weeks on 24-hour monitoring. Testim: +2.7/1.1 mm Hg23 |
| Hematocrit | Check hemoglobin and hematocrit periodically1 | Check before starting, at 3 to 6 months, then yearly3 |
| Hematocrit over 50% in one clinic review | 66.7% of men on injections | 12.8% of men on gels4 |
An injection puts a depot of testosterone ester in muscle. The Depo-Testosterone label says the ester is absorbed slowly, which is why it can be given every two to four weeks, and gives a half-life of about eight days.1 Levels rise after each shot and fall before the next one.
A gel is applied every day. The AndroGel 1.62% and Testim labels describe absorption continuing across the whole 24 hours, aiming for levels in the normal male range.23 Because it does not build a depot, levels fall back to about baseline within 48 to 72 hours of stopping AndroGel 1.62%.2
Every testosterone gel label carries a boxed warning: children who touched a user's skin or clothing have developed signs of virilization, such as an enlarged penis or clitoris, pubic hair and advanced bone age.23 In a transfer study, women who rubbed the application site 2 hours after a man applied AndroGel 1.62% had average testosterone levels rise 280% over their baseline.2
The labels ask users to wash hands after applying, cover the site with clothing once dry, and wash the site before skin-to-skin contact. Injections have no transfer risk.
No randomized trial has compared the two head to head for this. In one retrospective clinic review (47 men on gels, 57 on injections, 74 on pellets, followed up to 3 years), hematocrit over 50% was seen in 66.7% on injections vs 12.8% on gels. The injection group was younger and started with higher hematocrit, so the groups were not matched.4 Both labels ask for blood counts during treatment.13