Testosterone for Women: Why It's Part of HRT and How to Know If It's Working

Testosterone is not exclusively a male hormone. Women produce testosterone throughout their lives, and in younger women it is present in greater quantities than estrogen. It contributes to libido, muscle mass, bone density, energy, and cognitive focus. As women approach perimenopause, estrogen and progesterone decline sharply, but testosterone follows a more gradual trajectory, except in women who have their ovaries surgically removed, where levels can drop suddenly. Despite this, testosterone has historically been overlooked in female hormone care, largely because of the misconception that it is a male hormone.

Understanding how testosterone fits within the broader hormonal picture is one piece of a larger conversation about how menopause reshapes biology at the molecular level — and what that means for long-term health. To understand how all three hormones interact with biological aging, and how tools like GlycanAge can track whether hormone therapy is actually working, read our definitive guide: Menopause, HRT & Biological Age: The Definitive Guide to Tracking Hormonal Aging.

Why is testosterone included in HRT for women?

Testosterone is included in HRT when women present with low libido, reduced energy, or difficulty concentrating, which are symptoms that estrogen and progesterone alone do not fully address. Clinically, testosterone is typically prescribed as a 1% cream or gel, and only after a woman is well-estrogenized, meaning estrogen levels have been adequately restored first. This sequencing matters: testosterone's biological benefits depend partly on its conversion to estrogen through a process called aromatization, and blocking that conversion can produce pro-inflammatory effects rather than protective ones.

"Testosterone for women is very important. We produce about four times more testosterone than estrogen from our ovaries when we're younger."

— Dr. Louise Newson, Menopause Specialist and Founder, Newson Health

Does testosterone affect biological aging in women?

Testosterone influences biological aging primarily through its relationship with estrogen. Research by GlycanAge's scientific team, based on measurement of IgG glycosylation, the molecular switches that control chronic inflammation, shows that the beneficial effect of testosterone on immune aging depends on its conversion to estradiol. In a placebo-controlled study, men given testosterone alongside an aromatase inhibitor (which blocks conversion to estrogen) showed no positive effect on biological age; those who allowed conversion did. The same mechanism applies in women: IgG glycosylation, which governs the balance between pro- and anti-inflammatory immune activity, is controlled by estrogen in both sexes.

How does menopause accelerate biological aging and what does testosterone have to do with it?

Menopause triggers a measurable shift in immune biology. As estrogen, progesterone, and testosterone decline, IgG glycosylation is disrupted and anti-inflammatory glycans (complex sugars attached to immune antibodies) decrease while pro-inflammatory ones increase. This shift drives what scientists call inflammaging: the chronic, low-grade inflammation that accelerates biological aging and raises long-term disease risk. In a placebo-controlled trial, women whose estrogen was temporarily suppressed aged nine biological years within six months as measured by GlycanAge; women given estrogen back showed no aging effect. Testosterone contributes to this picture by supporting estrogen production and maintaining muscle and bone mass during the transition.

How do I know if my HRT, including testosterone, is actually working?

Symptom relief is a meaningful signal, but it does not confirm that HRT is reversing the underlying biological aging driven by hormone deficiency. GlycanAge measures whether the immune system is genuinely responding to treatment. At Raffaele Medical, New York, a postmenopausal woman started on transdermal estrogen, progesterone, and testosterone showed a six-year reduction in biological age within three months. In a second case, a woman six years post-menopause who had never used HRT began a regimen of transdermal estradiol, testosterone cream, oral DHEA, and progesterone; her GlycanAge reduced by eight years in three months and eleven years over twelve months, alongside measurable improvements in mood, energy, and function. These outcomes demonstrate that GlycanAge can validate whether HRT is working at a biological level, not just a symptomatic one.

"With optimized hormone replacement, I've seen patients drop 20–25 years off their GlycanAge. This isn't just about relieving menopausal symptoms — it's about showing measurable improvements in biological age and inflammation. For the first time, we can prove the systemic benefits of HRT with objective data, and that changes the conversation from short-term relief to long-term health and longevity."

— Dr. Joseph Raffaele, MD, Founder, Raffaele Medical

What does optimized HRT look like when testosterone is part of the protocol?

A structured clinical decision pathway guides testosterone prescribing within HRT. For women with a uterus who present with low libido, reduced energy, or poor focus, the recommended combination is estradiol (E2), micronized progesterone (P4), and testosterone (T). For women without a uterus who have the same symptoms, the same combination applies. Estradiol is preferred transdermally to minimize venous thromboembolism risk; oral estrogen is considered only where lipid profiles indicate it. Micronized progesterone (Utrogestan) is preferred over synthetic progestins, which carry higher VTE risk and do not share progesterone's benefits for sleep, mood, and cognitive function.

This pathway reflects clinical decision-making frameworks used by GlycanAge partner practitioners. Individual prescribing decisions should always be made in consultation with a qualified clinician.

Can testosterone in HRT cause harm if not monitored properly?

Yes, specifically when aromatase inhibitors are used alongside testosterone to keep testosterone levels artificially high. Blocking the conversion of testosterone to estrogen removes the primary mechanism through which testosterone protects against biological aging. Prof. Gordan Lauc, CSO and Co-founder of GlycanAge, has observed:

"Often people who are taking testosterone try to keep the testosterone level high by blocking the aromatase because testosterone is naturally being converted to estrogen — and if you do it, yes, you do have high testosterone, but your GlycanAge is increasing because you actually need estrogen."

— Prof. Gordan Lauc, Chief Scientific Officer, GlycanAge; Professor of Biochemistry and Molecular Biology, University of Zagreb

Dr. Joseph Raffaele has noted the same caution in clinical practice: clinicians who use aromatase inhibitors to keep testosterone artificially elevated are effectively removing the primary mechanism through which testosterone protects biological age. GlycanAge provides an objective measure of whether the hormonal protocol is producing an anti-inflammatory effect or inadvertently driving the opposite.

How often should I retest GlycanAge when I'm on HRT with testosterone?

The standard clinical recommendation is to establish a GlycanAge baseline before initiating HRT, then retest after the intervention to assess biological response. Meaningful changes in GlycanAge are detectable within three to four months of a well-calibrated HRT protocol. If GlycanAge improves, the protocol is producing a measurable anti-inflammatory effect. If it does not, the clinical pathway recommends reassessing and optimizing the estradiol component before adjusting testosterone. This retest cadence gives both clinician and patient objective data to guide titration decisions, moving HRT management beyond symptom checklists into measurable biology.

If you are on HRT or considering it and want to know whether your protocol is working at a biological level, a GlycanAge test gives you a baseline and a measurable outcome. Every test includes a 1:1 Result Interpretation Call with a longevity specialist who can walk you through your biological age, your glycan indexes, and what your results mean in the context of hormone therapy.

Order your GlycanAge test kit → Shop GlycanAge

For clinicians integrating GlycanAge into HRT and menopause protocols, the Healthcare Providers page outlines how to baseline patients, monitor intervention response, and use biological age data to support clinical decision-making.

Use GlycanAge in your practice → Healthcare Providers

External sources

• https://insight.jci.org/articles/view/89703 — Ercan A, et al. Estrogens regulate glycosylation of IgG in women and men. JCI Insight. 2017;2(4):e89703.

• https://pubmed.ncbi.nlm.nih.gov/33049709/ — Jurić J, et al. Effects of estradiol on biological age measured using the glycan age index. Aging (Albany NY). 2020;12(19):19756–19780.