What Happens When Women Inject Testosterone?

Happy Friday!

Each week, I spend several hours contemplating how I can bring the most valuable information to my readers and subscribers.

One of the data sources I use is my question box, where anyone can send me a video topic or question they think I should address.

Without fail, one of the single most requested topics is how women in their 40s, 50s, and 60s can optimize their health.

I can’t count the number of emails and messages I get from women asking about the fatigue, mood swings, muscle loss, low libido, and “just not feeling like myself” that so often creeps in during midlife.

If you’re a woman in your 40s or 50s, there’s a high likelihood you’ve felt the impact of hormonal shifts.

You may already be dabbling in peptides, or perhaps you’re hearing more about them in health circles every day.

Peptides can be truly life-changing for tissue repair, gut healing, inflammation, and mitochondrial support.

HOWEVER, no amount of BPC-157, MOTS-c, Retatrutide, or any other peptide is going to fix the root hormonal imbalance if your testosterone levels have tanked.

I see this over and over.

Women are searching for the next best peptide protocol or supplement stack, but nobody is talking about their fundamental sex hormone levels.

As a result, they chase symptoms but never address the cause.

So let’s put peptides aside for a minute and talk about the elephant in the room.

Testosterone deficiency in women…and what happens when you fix it.

Today, we will look at what happens when women inject testosterone.

Peptides Are Powerful, But They Can’t Replace Your Hormones

If you want to heal faster, recover from injury, or optimize your gut, peptides are often the fastest path to results.

But suppose you’re a woman in perimenopause or postmenopause with classic symptoms of low testosterone. In that case, even the most advanced peptide stack on earth won’t restore what your ovaries are no longer producing. 

Hormones are the orchestra conductors for nearly every system in your body, from muscle protein synthesis and metabolism to brain chemistry, sexual desire, and energy levels.

This is the missing link for so many women.

You MUST fix the hormone deficit first, then layer in peptides, supplements, and advanced therapies to achieve truly optimal health.

And the most overlooked hormone of all?

Testosterone.

What Happens When Women Inject Testosterone

One of the best studies ever done on injectable testosterone in women is the 2014 clinical trial by Huang et al., published in the Journal of Clinical Endocrinology & Metabolism (full text here).

This was a 24-week, double-blind, randomized, placebo-controlled dose-ranging trial looking specifically at the effects of injectable testosterone enanthate in women who had undergone hysterectomy.

The researchers enrolled 71 women and randomized them to weekly IM injections of testosterone enanthate at 3 mg, 6.25 mg, 12.5 mg, or 25 mg, or a placebo.

All women also received a baseline dose of estrogen.

Results

The results were nothing short of dramatic, especially at the higher, but still physiologically relevant, doses.

Sexual Desire and Function

• The primary measure was the change in sexual function (using the Profile of Female Sexual Function, PFSF). Only the 25 mg/week group had a statistically significant improvement compared to placebo.

• On average, the 25 mg group saw an increase in the frequency of satisfying sexual activity from 2.7 to 4.4 encounters per month, compared to virtually no change in placebo (2.6 to 2.8/month). That’s a +63% increase in sexual activity over six months.

• Sexual desire, arousal, and responsiveness scores rose by 30–40% over baseline in the highest dose group, while lower doses had more modest improvements.

Body Composition and Strength

• Lean body mass increased by 1.8 kg (about 4 pounds) in the 25 mg group over 24 weeks. Placebo saw a trivial change of just 0.3 kg. That’s a 500% greater gain in muscle mass with testosterone injection compared to no treatment.

• Muscle power and strength (chest-press power and loaded stair-climbing power) improved by 13–14% in the high-dose group, with negligible changes in the placebo and low-dose groups.

• Total fat mass was stable or slightly decreased, with the muscle gain largely coming from improved protein synthesis and recovery.

Mood, Well-being, and Quality of Life

• While the study was not powered to detect big differences in mood, women reported noticeable improvements in energy, well-being, and satisfaction, especially in those who started with the most severe symptoms.

Safety and Side Effects

• Importantly, the study tracked androgenic side effects like hair growth, acne, and voice deepening. Rates were low, and side effects were generally mild and reversible when they did occur.

• There were no cases of severe virilization, adverse lipid effects, or metabolic complications within the 24-week timeframe at any dose.

Percentage Improvements

To sum up, here’s what the highest-dose group (25 mg/week) achieved compared to placebo after 24 weeks:

• Satisfying sexual activity: +63% increase (from 2.7/month to 4.4/month)

• Sexual desire/arousal/responsiveness: +30–40% increase in validated scale scores

• Lean muscle mass: +1.8 kg vs +0.3 kg in placebo (roughly 500% more muscle gain)

• Muscle power/strength: +13–14% improvement vs no change in placebo

• Androgenic side effects: No significant difference from placebo at physiologic doses

If you translate these numbers into real-world results, you’re talking about more energy, stronger muscles, higher libido, more fulfilling sex, and a return of that “spark” you thought was gone for good.

Who Should Consider Injectable Testosterone?

So which women are good candidates for injectable testosterone?

• Low sexual desire or satisfaction

• Fatigue, low energy, or loss of motivation

• Muscle weakness, loss of muscle tone, or decreased physical function

• Mood shifts, reduced well-being, or just feeling “off”

Importantly, while this particular study looked at hysterectomized women, the principles extend to all women experiencing symptomatic testosterone deficiency, especially as estrogen and testosterone levels decline with age.

If you’re in your 40s, 50s, or even early 60s and ticking these boxes above, you’re exactly the person who could benefit most from proper evaluation and, if appropriate, low-dose injectable testosterone therapy.

You don’t need to wait until you’re “falling apart” to ask about it, either.

The women in this study saw the biggest benefits when they started with the most severe symptoms, but even moderate issues improved meaningfully.

The Bottom Line

If you take one thing away from this email, let it be this.

Peptides are amazing, but they cannot replace your core sex hormones. 

You can stack BPC-157, TB-500, SS-31, and every other cutting-edge molecule, but if your testosterone is bottomed out, you’re playing health optimization on “hard mode.”

The data is clear.

Restoring testosterone to healthy levels in symptomatic women leads to transformative changes, including more muscle, more energy, better sex, and a revitalized sense of self. 

And the safest, most effective way to do that, when peptides and lifestyle aren’t enough, is with low-dose injectable testosterone.

Want to know if you’re a candidate? Start by testing your hormone levels, then talk to a clinician who understands the power of injectable testosterone for women.

Peptides will take you further, but they can’t take you all the way if your hormonal foundation is broken. 

Don’t settle for anything less than optimal.

Your health, energy, and happiness are worth it.

Best,

Hunter Williams

References

• Huang G, et al. “Testosterone Dose-Response Relationships in Hysterectomized Women with or without Oophorectomy: Effects on Sexual Function, Body Composition, Muscle Performance, and Physical Function in a Randomized Trial.” J Clin Endocrinol Metab. 2014 Jun;99(6):E1287-E1296. Full Text