Do Sub-Q Testosterone Injections Trigger Excessive Estrogen? – T NATION+ – COMMUNITY

TRT and Subcutaneous Administration

Injecting testosterone subcutaneously versus intramuscularly has its advantages, nevertheless it may also have drawbacks. Right here’s what it is advisable know.

The recognition of subcutaneous or sub-Q injections for testosterone substitute remedy (TRT) is on the uptick. As an alternative of injecting into the muscle – intramuscular or IM – you inject into the fatty layer slightly below the pores and skin, normally within the butt or stomach.

Proponents of sub-Q injection consider this methodology offers you extra bang in your buck. The late Dr. John Crisler stated that 80 mg of sub-Q testosterone has the impact of 100 mg of testosterone administered intramuscularly, and it results in extra secure T ranges. And, after all, with sub-Q, there’s no muscle scarring, smaller needles, and fewer ache.

Nevertheless, a number of papers examined estrogen (estradiol or E2) ranges after sub-Q testosterone administration. They’re clearly elevated when in comparison with the intramuscular route. In males, excessive estrogen ranges are related to low libido, erectile dysfunction, infertility, temper swings, and low power.

Research 1

In a 52-week examine of 150 males who certified for TRT, topics self-administered both 50, 75, or 100 mg of testosterone enanthate weekly through sub-Q auto-injection (1). This was after a 6-week interval the place all topics acquired 75 mg per week, after which the dose was titrated up or down. After 12 weeks, blood was drawn and analyzed at varied instances after the final injection.

Apparently, common estrogen concentrations have been 46.3 pg/ml, whereas the height plasma focus was 64.2 pg/ml. The authors additionally reported an estrogen-to-total testosterone ratio of 0.93%. Confusingly, they didn’t trouble to report these information by dose, so it’s unclear what dose these values mirror. The reference vary for estrogen was 10-50 pg/ml.

A 100 mg dose of testosterone enanthate given sub-Q produced testosterone concentrations higher than 50% of these seen with 200 mg of testosterone enanthate given IM. However the estrogen concentrations have been basically the identical, reflecting a skewed conversion to estrogen.

Research 2

In a 6-week examine of 39 males, topics self-administered both 50 or 100 mg of testosterone enanthate weekly through sub-Q or a 200 mg dose of testosterone enanthate IM (2). Blood was once more drawn after 6 weeks and evaluated. Right here, the common estrogen ranges have been 25.6, 48.3, and 50.0 pg/ml, respectively. The ratio for estrogen to whole testosterone was 0.0063, 0.0055. and 0.0032, respectively.

As soon as once more, these information show a skewed conversion of testosterone to estrogen. The estrogen to whole testosterone ratio for sub-Q administration was practically twice that of IM.

Research 3

In a 26-week examine of 133 males, a subgroup of topics self-administered 75 mg of testosterone enanthate weekly through sub-Q (3). Blood was drawn after 1, 6, and 12 weeks. Once more, as soon as steady-state estrogen ranges are reached round week 6, these values are, on common, past the reference vary of 10-50 pg/ml.

Why Does This Occur?

It’s troublesome to say why sub-Q administration results in higher estrogen ranges than the IM route. Nevertheless, we will rule out the notion that greater whole quantities of testosterone can be found as a result of the world beneath the curve (AUC) values for whole T are pretty linear between the 2 routes, confirming they’ve comparable bioavailability (2).

It’s additionally unlikely that the upper dose of IM testosterone (evaluating a 100 mg dose sub-Q vs. a 200 mg dose IM) leads to saturation of the aromatase enzyme (4).

Adipose tissue (fats) is a serious web site of aromatase exercise in males, particularly contemplating its relative exercise in comparison with muscle (virtually two-fold higher). So that is most likely the primary issue. (5).

This additionally suits with the information demonstrating that sub-Q administration produces an estrogen-to-total testosterone ratio round two-fold higher in comparison with IM. Whereas skeletal muscle occupies a higher quantity of physique mass in comparison with fats, we’re solely involved with its relative exercise as a result of this can be a localized administration.

Some restricted proof means that exogenous testosterone administration could enhance aromatase expression in adipose tissue (6). Nevertheless, the enzyme wouldn’t be saturated, leaving aromatase accessible to proceed binding to and catalyzing the formation of testosterone to estrogen. Even when aromatase expression have been elevated, if extra substrate (testosterone) isn’t accessible, this shouldn’t make any distinction.

What Ought to You Do?

In case your estrogen ranges are usually monitored as a part of your TRT blood work and are within the regular vary, there’s no want to vary something. Whereas relative estrogen ranges do seem greater, there was substantial variation with some people going over the traditional reference vary in these research. Others have been nicely beneath it.

For those who’re simply beginning TRT and utilizing sub-Q, test your estrogen ranges when you’ve been utilizing it for at the least 6 weeks and see the place they’re. In the event that they’re elevated nicely past the traditional vary, speak to your doc about adjusting the dose or utilizing another route of administration. Doubtlessly, you would possibly want a really low dose of an aromatase inhibitor. You may additionally need to take into account free estrogen ranges.

Take-House Factors

  • Sub-Q testosterone administration can enhance estrogen blood ranges in comparison with IM.
  • There may be substantial variation: not all people may have values out of the traditional reference vary.
  • The principle issue contributing to that is seemingly the aromatase exercise in fats in comparison with skeletal muscle.
  • Have your estrogen (estradiol or E2) ranges checked after utilizing sub-Q administration for at the least 6 weeks.
  • If estrogen is simply too excessive, speak to your doctor about switching routes, dose, or taking a really low dose of an aromatase inhibitor.
  • For those who really feel effective and your estrogen ranges are inside the regular vary or near it, there’s no want to vary something except your doc feels otherwise.

The pure T booster:




  1. Kaminetsky JC, McCullough A, Hwang Okay, Jaffe JS, Wang C, Swerdloff RS. A 52-Week Research of Dose Adjusted Subcutaneous Testosterone Enanthate in Oil Self-Administered through Disposable Auto-Injector. J Urol. 2019 Mar;201(3):587-594. doi: 10.1016/j.juro.2018.09.057. PMID: 30296416.
  2. Kaminetsky J, Jaffe JS, Swerdloff RS. Pharmacokinetic Profile of Subcutaneous Testosterone Enanthate Delivered through a Novel, Prefilled Single-Use Autoinjector: A Part II Research. Intercourse Med. 2015 Sep 17;3(4):269-79. doi: 10.1002/sm2.80. PMID: 26797061; PMCID: PMC4721027.
  3. Gittelman M, Jaffe JS, Kaminetsky JC. Security of a New Subcutaneous Testosterone Enanthate Auto-Injector: Outcomes of a 26-Week Research. J Intercourse Med. 2019 Nov;16(11):1741-1748. doi: 10.1016/j.jsxm.2019.08.013. Epub 2019 Sep 21. PMID: 31551193.
  4. Lakshman KM, Kaplan B, Travison TG, Basaria S, Knapp PE, Singh AB, LaValley MP, Mazer NA, Bhasin S. The consequences of injected testosterone dose and age on the conversion of testosterone to estradiol and dihydrotestosterone in younger and older males. J Clin Endocrinol Metab. 2010 Aug;95(8):3955-64. doi: 10.1210/jc.2010-0102. Epub 2010 Jun 9. PMID: 20534765; PMCID: PMC2913038.
  5. Longcope C, Pratt JH, Sub-Qhneider SH, Fineberg SE. Aromatization of androgens by musub-Qle and adipose tissue in vivo. J Clin Endocrinol Metab. 1978 Jan;46(1):146-52. doi: 10.1210/jcem-46-1-146. PMID: 752017.
  6. Ghanim H, Dhindsa S, Abuaysheh S, Batra M, Kuhadiya ND, Makdissi A, Chaudhuri A, Dandona P. Diminished androgen and estrogen receptors and aromatase ranges in hypogonadal diabetic males: reversal with testosterone. Eur J Endocrinol. 2018 Mar;178(3):277-283. doi: 10.1530/EJE-17-0673. Epub 2018 Jan 16. PMID: 29339527.
  7. Frederiksen H, Johannsen TH, Andersen SE, Albrethsen J, Landersoe SK, Petersen JH, Andersen AN, Vestergaard ET, Sub-Qhorring ME, Linneberg A, Major KM, Andersson AM, Juul A. Intercourse-specific Estrogen Ranges and Reference Intervals from Infancy to Late Maturity Decided by LC-MS/MS. J Clin Endocrinol Metab. 2020 Mar 1;105(3):754–68. doi: 10.1210/clinem/dgz196. PMID: 31720688; PMCID: PMC7007877.
  8. Stanczyk FZ, Clarke NJ. Measurement of estradiol–challenges forward. J Clin Endocrinol Metab. 2014 Jan;99(1):56-8. doi: 10.1210/jc.2013-2905. Epub 2013 Dec 20. PMID: 24178793.

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