Testosterone pellets vs. sublinguals vs. creams: what the absorption data actually shows

What did @fullonkaren actually say?

Karen says she used a testosterone pellet to reach her target level of 175 ng/dL total testosterone, then switched to a sublingual and a cream. Her follow-up labs came back at 53 ng/dL, and she attributes the drop entirely to poor absorption from those two delivery methods. She's going back to injections. She also mentions a biotin interference issue that temporarily gave her a false reading of 1100 ng/dL, which she says she immediately doubted.

Worth noting: she's not making wild claims here. She's reporting her own lab results and drawing a logical conclusion from them. That's more self-aware than most TRT content on this platform. But there are a few things worth unpacking before you take her experience as a universal lesson.

Does the science back this up?

Partially, yes. Absorption variability with non-injection testosterone delivery is real and well-documented. But the full picture is more complicated than "cream and sublingual don't work."

Pellet implants deliver supraphysiologic doses that gradually release over 3 to 6 months. When you remove that steady hormonal input, your levels will drop, sometimes sharply, regardless of what you switch to. A 2021 review by Glaser and Dimitrakakis in Maturitas found that pellet therapy in women produces higher and more stable serum testosterone than topical formulations, but they also noted that the comparison isn't straightforward because pellet dosing is calibrated very differently.

Sublingual testosterone does have absorption issues in some patients. A 2019 pharmacokinetic study by Finkielstain et al. in The Journal of Clinical Endocrinology and Metabolism found significant inter-individual variability in sublingual delivery. Transdermal creams can work, but they require careful application site selection and consistency. Scrotal or inner arm application changes absorption dramatically compared to general skin.

The drop from pellet levels to 53 ng/dL after switching is plausible. Whether the sublingual and cream were dosed adequately for her body is a separate question the data doesn't answer.

What did they get wrong (or right)?

She got the biotin interference point right. Biotin, even at supplement doses, can falsely elevate immunoassay-based hormone panels. The FDA issued a safety communication about this in 2017. Her skepticism about the 1100 ng/dL result was clinically sound.

Where she oversimplifies: saying "that just shows what is not being absorbed" treats her single case as proof that sublingual and cream are ineffective delivery systems. They're not ineffective for everyone. They're variable, and they require dose titration that pellets don't because pellets are essentially a fixed slow-release implant. If her prescriber simply converted her pellet dose to a sublingual equivalent without accounting for the different pharmacokinetics, that's a prescribing problem, not just an absorption problem.

Her target of 175 ng/dL total testosterone is also on the higher end for women. Most clinical guidelines, including those from the Endocrine Society, use a reference range of 15 to 70 ng/dL for premenopausal women. That doesn't make her wrong to prefer 175, but it does mean her therapeutic target requires more aggressive dosing regardless of delivery method.

What should you actually know?

If you're switching testosterone delivery methods, your levels will not be equivalent on day one. Pellets are a slow-release depot system. When you stop them, you're not just changing delivery, you're losing a hormone reservoir that was built up over months. Any replacement therapy needs time and dose titration to reach the same serum level.

Injection-based testosterone, typically cypionate or enanthate, does produce more predictable and reproducible serum levels than transdermal or sublingual routes for most patients. A 2020 comparative study by Wierckx et al. in Andrology confirmed this pattern in the context of gender-affirming hormone therapy, which uses similar pharmacology. That's probably why Karen feels better on injections, and that's a legitimate reason to prefer them.

What this video should not make you do is assume sublingual and cream are universally useless. They work for a lot of people. They didn't work well enough for her at the doses she was given. Those are different statements.

If your levels drop after switching delivery methods, ask your provider whether the dose was recalculated for the new route, not just converted by weight.