Post TRT - Libido is DEAD :(

[Phil Goodman]

Prompt using Claude:

I’d like to compare various protocols of trt. For an average 200 lb man, review the literature to make a best guess about what his total testosterone blood levels would be for the following doses.
50 mg testosterone cypionate once per week
25 mg testosterone cypionate twice per week
100 mg testosterone cypionate once per week
50 mg testosterone cypionate twice per week
Take your time and confirm accuracy before responding





Response from Claude:

Good, I now have solid data. Let me synthesize this carefully using the pharmacokinetic literature and the key anchor points from clinical studies.
Here’s a thorough breakdown based on the published literature. I’ll note upfront that the exact numbers in this kind of analysis depend on baseline endogenous production (assumed to be suppressed at steady-state), individual metabolism, SHBG levels, body composition, and whether injections are intramuscular or subcutaneous. The figures below represent reasonable population averages at steady state, with typical ranges reflecting real inter-individual variation.

Key pharmacokinetic anchors from the literature
The half-life of testosterone cypionate when injected intramuscularly is approximately eight days. This means at steady state (roughly 5 half-lives, or 5–6 weeks of consistent dosing), drug accumulates meaningfully between doses. Importantly, intramuscular administration of 200 mg of testosterone cypionate produced a mean supratherapeutic Cmax of 1,122 ng/dL occurring 4–5 days post-injection. That’s a well-established anchor for scaling.
In a clinical study of hypogonadal men treated with IM testosterone cypionate 100 mg weekly, trough total testosterone rose from a baseline of ~314 ng/dL to ~536 ng/dL post-treatment. That trough figure is key for calibrating the 100 mg/week once-weekly protocol.
The pharmacokinetics are essentially linear and dose-proportional at TRT doses, so the numbers below scale accordingly.

Protocol Comparisons (at steady state, average 200 lb man)
1. 50 mg testosterone cypionate once per week
∙ Weekly total dose: 50 mg
∙ Peak (day 2–3): ~400–500 ng/dL
∙ Trough (day 6–7, pre-injection): ~250–350 ng/dL
∙ Average/mid-week: ~350–420 ng/dL
∙ Peak-to-trough swing: moderate (~150–200 ng/dL fluctuation)
This is a low-dose protocol. Many men will land in the low-normal range and may hover near or below the 300 ng/dL threshold by injection day. It’s a reasonable starting/conservative protocol but may leave some men symptomatic near trough.

2. 25 mg testosterone cypionate twice per week (same 50 mg/week total)
∙ Weekly total dose: 50 mg (same as above)
∙ Peak (day 1–2 after each injection): ~350–430 ng/dL
∙ Trough (day 3–4, pre-injection): ~280–360 ng/dL
∙ Average: ~350–420 ng/dL
∙ Peak-to-trough swing: much smaller (~70–100 ng/dL fluctuation)
Because the total weekly dose is identical, the average level is essentially the same as Protocol 1. The key difference is dramatically improved stability — the shorter dosing interval relative to the half-life keeps levels far more consistent. The cypionate half-life of ~8 days means 25 mg every 3.5 days produces very smooth, near-flat kinetics. This is arguably the most physiologically stable low-dose option.

3. 100 mg testosterone cypionate once per week
∙ Weekly total dose: 100 mg
∙ Peak (day 2–3): ~700–900 ng/dL
∙ Trough (day 6–7, pre-injection): ~450–550 ng/dL
∙ Average/mid-week: ~550–700 ng/dL
∙ Peak-to-trough swing: significant (~300–400 ng/dL fluctuation)
This is the most commonly studied standard TRT dose. Clinical data from men on 100 mg IM-TC weekly showed trough levels reaching ~536 ng/dL , which aligns well with this estimate. The Endocrine Society Clinical Practice Guidelines target a therapeutic level of 400–700 ng/dL measured one week after a dose of TC. Once-weekly dosing at this amount produces meaningful peaks and troughs — some men feel the difference.

4. 50 mg testosterone cypionate twice per week (same 100 mg/week total)
∙ Weekly total dose: 100 mg (same as above)
∙ Peak (day 1–2 after each injection): ~600–750 ng/dL
∙ Trough (day 3–4, pre-injection): ~500–650 ng/dL
∙ Average: ~550–700 ng/dL
∙ Peak-to-trough swing: much smaller (~100–150 ng/dL fluctuation)
Again, the average testosterone exposure is identical to Protocol 3, but the curve is dramatically flatter. Splitting doses to 50 mg twice weekly is specifically recommended to avoid the high peaks and troughs seen with less frequent injections. This is widely considered the “gold standard” TRT protocol among endocrinologists for stable symptom management, lower estradiol peaks, and reduced hematocrit elevation.

Important caveats
∙ These are population averages. Individual variation is substantial — SHBG, body fat, metabolic rate, injection site, and whether injection is IM vs. subcutaneous all shift results meaningfully.
∙ Subcutaneous injection of the same dose tends to produce slightly lower, smoother peaks than IM.
∙ Endogenous production is assumed to be largely suppressed at steady state, which typically occurs by weeks 5–6.
∙ A 200 lb man’s weight has a modest effect on distribution volume, but the PK modeling literature suggests weight is not a major driver of average levels at these doses — the effect is smaller than most people assume.
∙ Real blood work is irreplaceable. These estimates are useful for protocol planning but not for replacing lab monitoring.

 

[Phil Goodman]

Not one study saying that it is appropriate to start TRT with supraphysiological levels of testosterone. Many saying to start at mid-physiological levels. End of story. Go away.

Lmfao take the fucking L guy

 

[Cataceous]

Lmfao take the fucking L guy

As if AI vomitus could save the day for you.

The half-life of testosterone cypionate when injected intramuscularly is approximately eight days.​

Garbage-in, garbage out... That figure stems from old research that did not account for the interference of natural production.†

Still waiting for that study that says initial dosing to supraphysiological levels is appropriate. Apparently now you're trying to argue that supraphysiological dosing does not lead to supraphysiological levels. Explain how that works. How does taking an average of 10 mg per day of testosterone result in normal levels in the average guy when average production for healthy young guys is only 6.5 mg?

Basically you're advocating for at least half the guys to experience supraphysiological levels, while most of the rest have levels higher than their healthy natural best. Do you honestly think this is good medical practice? It wouldn't be considered such with any other hormone, More-is-better thinking around testosterone degrades good judgement.

†From smarter AI: The half-life of generic injectable testosterone cypionate formulations is approximately 4.8 days, based on population pharmacokinetic modeling in healthy adult men that mathematically accounts for endogenous testosterone production and its suppression via the HPTA during administration. This estimate comes from a 2018 study that used compartmental analysis to separate exogenous drug kinetics from variable endogenous secretion rates (estimated at 11.9–13 mg/day basally, with dose-dependent suppression). Traditional non-compartmental methods, which do not adjust for endogenous interference, often overestimate the half-life at 6.9–8 days due to flip-flop pharmacokinetics where the slow release from the oil depot is rate-limiting, and residual natural production prolongs the apparent decline in measured levels.​

 

[Phil Goodman]

As if AI vomitus could save the day for you.

The half-life of testosterone cypionate when injected intramuscularly is approximately eight days.​

Garbage-in, garbage out... That figure stems from old research that did not account for the interference of natural production.†

Still waiting for that study that says initial dosing to supraphysiological levels is appropriate. Apparently now you're trying to argue that supraphysiological dosing does not lead to supraphysiological levels. Explain how that works. How does taking an average of 10 mg per day of testosterone result in normal levels in the average guy when average production for healthy young guys is only 6.5 mg?

Basically you're advocating for at least half the guys to experience supraphysiological levels, while most of the rest have levels higher than their healthy natural best. Do you honestly think this is good medical practice? It wouldn't be considered such with any other hormone, More-is-better thinking around testosterone degrades good judgement.

†From smarter AI: The half-life of generic injectable testosterone cypionate formulations is approximately 4.8 days, based on population pharmacokinetic modeling in healthy adult men that mathematically accounts for endogenous testosterone production and its suppression via the HPTA during administration. This estimate comes from a 2018 study that used compartmental analysis to separate exogenous drug kinetics from variable endogenous secretion rates (estimated at 11.9–13 mg/day basally, with dose-dependent suppression). Traditional non-compartmental methods, which do not adjust for endogenous interference, often overestimate the half-life at 6.9–8 days due to flip-flop pharmacokinetics where the slow release from the oil depot is rate-limiting, and residual natural production prolongs the apparent decline in measured levels.​

you’re basing that half life on one study which just used a model to try and estimate it while accounting for endogenous interference, which is a non-factor in a trt patient because their natural production is shut down. The model also didn’t accurately predict what we see in the real world. There’s a reason the 7-8 day half life is used and even acknowledged by the FDA.

From an even smarter AI




KEY POINT HERE:

When the authors assumed endogenous testosterone secretion was zero in their population PK analysis, the median estimated half-life increased to 6.87 days — very close to the traditional non-compartmental estimate.
So your instinct was exactly right, and the answer is clear:
The 4.05-day figure is not really a better half-life estimate — it’s an artifact of the modeling approach. The model mathematically separated exogenous TC kinetics from endogenous production, and in doing so, attributed some of the measured testosterone to endogenous sources rather than the drug. When you strip that out and assume zero endogenous production — which is the correct assumption for an established TRT patient — the half-life reverts to ~6.87 days, nearly identical to the traditional estimate.

The bottom line: the ~6.87–8 day half-life is the correct figure to use for predicting blood levels on TRT, and my original estimates in the first table hold up better than the 4-day recalculation. The “smarter AI” was technically describing a real finding from the paper, but presenting it in a way that overstated its practical relevance for TRT planning.



Like I said, take the L. I’ve shown you all you need to see but for whatever reason(s) you either fail to acknowledge it or fail to admit. And I’m not even trying to convince you anymore, just putting this information out for anyone else who is interested in reading it.


Like I said earlier, you are more than welcome to your own opinion. But when you promote protocols that have been proven to make men weaker, fatter, more frail, and overall less healthy then don’t be surprised if you receive pushback.

 

[Cataceous]

... But when you promote protocols that have been proven to make men weaker, fatter, more frail, and overall less healthy then don’t be surprised if you receive pushback.

You rely on a straw man argument by making the comparison to a protocol that induces hypogonadism; after all this verbiage you still have not cited one study that directly compares our positions. You also don't respond to the assertion that your approach to TRT is out of line with science-based medical practice. What does your AI say about the choice between starting guys on TRT with midrange physiological levels versus putting most of them over-range, which 100 mg TC per week absolutely does?

 

[Phil Goodman]

You rely on a straw man argument by making the comparison to a protocol that induces hypogonadism; after all this verbiage you still have not cited one study that directly compares our positions. You also don't respond to the assertion that your approach to TRT is out of line with science-based medical practice. What does your AI say about the choice between starting guys on TRT with midrange physiological levels versus putting most of them over-range, which 100 mg TC per week absolutely does?

The studies induced hypogonadism in order to more accurately assess long term treatments. By eliminating natural production before starting it more accurately reflects the impact on a body in which endogenous t isn’t a factor(which it won’t be for people on trt).

Meanwhile you share a study that factors in endogenous production to calculate the half life… then come up with an inaccurate number of around 4 days before the authors themselves wrote: “When we assume endogenous testosterone secretion is 0 in the PPK analysis, the median estimated half-life increases to 6.87 days.” And to make it even more hilarious you used that as if it was a counter to my calculations which discredited the levels seen from the various doses.


Similarly, you shared a “study”… that was actually just a review of studies from talking heads in which they concluded that 100 mg/week is a good starting dose… while acting like it supported your narrative and countered mine.


Again, I’ve shared tons of studies to support my assertions. I’ve also shown the negative effects of starting at your suggested dose of 50 mg/week. And no… splitting the suboptimal dose of 50 per week doesn’t magically fix all of the issues with it as far as muscle, bone, fat, and other effects are concerned.



The more you go on the worse it looks. Like I said, you should’ve taken the L a LONG time ago. Continuing to dig this hole is not getting you anywhere