Trans guy's testosterone testing video gets the basics right

What did @lukaelias7 actually say?

Luca switched from testosterone injections to gel, then spent roughly three months using expired product and missing doses. "I completely forgot" to apply it some days, and on others applied it in the evening instead of morning. He's now getting labs to check where his testosterone levels landed after all of this.

This is a pretty common scenario, honestly. Gel users miss doses, forget timings, and plenty of people use medications past their printed expiration dates without thinking much about it. Luca isn't doing anything shocking here, but there are real clinical consequences worth unpacking. The setup he describes is essentially a perfect storm for inconsistent testosterone delivery, and his blood results are going to reflect that whether he likes it or not.

Does the science back this up?

Yes, mostly. The concerns Luca's situation raises are well-supported. Inconsistent application timing and missed doses with transdermal testosterone genuinely do produce erratic serum levels. A 2019 study by Dobs et al. in Andrology confirmed that transdermal testosterone produces significantly more day-to-day variability than injections, and that variability is made worse by application inconsistency.

On the expired gel question, this is where it gets more nuanced. FDA guidance and pharmaceutical stability data generally show that expired topical preparations lose potency over time, particularly after opening, but the rate depends on storage conditions. A 2012 review by Blessy et al. in the Journal of Applied Pharmaceutical Science outlined how temperature, humidity, and light exposure accelerate degradation in topical gels. Three months of expired product under suboptimal storage could mean meaningfully reduced testosterone delivery, not zero, but less than labeled. Nobody has done a randomized trial on "how bad is three-month-expired testosterone gel specifically," so we're reasoning from stability science here.

What did they get wrong (or right)?

Credit where it's due: Luca actually did the right thing by getting labs. That's the correct response to three months of inconsistent therapy. He's treating this like a data problem, not ignoring it.

What he underplays is how compounding these two issues matters. Missing doses with gel isn't like missing an injection. Because testosterone gel maintains levels through daily absorption, skipping days doesn't just mean one low day. Research by Wang et al. (2000, Journal of Clinical Endocrinology and Metabolism) showed that serum testosterone from topical formulations drops noticeably within 24 hours of missed application. String together multiple missed doses plus reduced potency from expired product and you're looking at potentially weeks of subtherapeutic levels, not just a minor dip.

The evening application habit is also a real issue, not just a timing preference. Morning application aligns with natural diurnal patterns and reduces transfer risk to partners or children during peak absorption windows. Applying in the evening isn't disqualifying, but it's not equivalent to morning dosing either.

What should you actually know?

Expired medications are not a binary fine-or-dangerous situation. Degraded potency is the main concern with expired topical testosterone, not toxicity. But for someone on hormone replacement, "less than labeled potency" is a clinical problem. You may be running on subtherapeutic levels without obvious symptoms until labs catch it.

Missed doses with gel have a different pharmacological profile than missed injections. Testosterone enanthate or cypionate injections have a multi-week half-life, so one missed shot stings but doesn't crater you overnight. Gel doesn't work that way. It requires daily adherence to maintain steady-state levels, and the margin for error is tighter.

If you've had months of inconsistent therapy, labs are the right call before adjusting anything. Don't guess based on symptoms alone. Testosterone interacts with red blood cell production, mood, and metabolism in ways that can lag behind actual serum levels. Get the number first.

• Always check expiration dates on topical formulations before use, especially after switching from injections.
• If you miss a morning application, applying later that day is generally better than skipping entirely, but check with your prescriber.
• Store testosterone gel away from heat and humidity to preserve stability.
• Labs after a period of disrupted therapy should include total testosterone at minimum, and ideally free testosterone as well.