How to Increase Testosterone Naturally After 40

In the previous article, we covered what declining testosterone actually looks like in masters athletes — the five signs, why the after-40 picture is different from a younger athlete's, and why standard bloodwork frequently misses the most important part of the story.

Today is about what you actually do about it.

One mistake worth addressing immediately, because it's extremely common: reaching for a single supplement and expecting it to move the needle on its own. That's not how this works — and it matters even less at this stage of life than it would for someone in their 20s. You have less hormonal margin now. The inputs that control testosterone are interconnected, and after 40 they're frequently being undermined simultaneously in ways that compound rather than simply add up.

A targeted supplement on top of an unaddressed foundation is a weak intervention. Fix the foundation first. Here's what that actually means for masters athletes.

Prefer to watch? The full video is below — or keep reading for the expanded breakdown

1. Energy Availability — The Most Overlooked Driver

When caloric intake doesn't match training load, your body interprets that as scarcity. In a scarcity state, anabolic processes get deprioritized. Testosterone production drops because the internal signal is that this isn't a good time to build.

This is not new physiology — it affects athletes at any age. What makes it specific to masters athletes is the behavioral pattern it runs into.

As metabolism shifts with age and body composition becomes harder to manage, many athletes respond by pulling back on calories. The logic is intuitive: if weight is creeping up despite the same training, eat less. But when caloric intake is chronically below what training, recovery, tissue repair, and hormonal function actually require, the hormonal system pays the price — directly and measurably.

The athlete this hits hardest in the over-40 group is someone training at meaningful volume, deliberately staying lean as a response to age-related body composition changes, and under-fueling as a result. From the outside it looks disciplined. Hormonally, it's actively working against the very outcomes they're trying to achieve — at exactly the stage of life when hormonal buffer is smallest.

The mindset shift required: the caloric intake that worked at 30 may genuinely not be enough at 45, especially relative to your training load. Eating enough to support training, recovery, tissue repair, and hormonal function isn't indulgence — it's the non-negotiable foundation everything else depends on. The number of masters athletes quietly suppressing their own testosterone through disciplined under-fueling is significant and consistently underappreciated.

2. Training Load and Recovery Balance — Where the Math Changes Most

Training raises testosterone — but only when it's balanced with adequate recovery. When training volume is chronically high or recovery is consistently inadequate, cortisol stays elevated. And as covered in the previous article, cortisol directly suppresses testosterone through competition for shared adrenal precursor hormones.

The aging-specific issue: your hormonal buffer shrinks with age. Baseline testosterone production is already declining. So the same cortisol elevation that your hormonal system absorbed without much consequence at 30 now tips the ratio meaningfully further in the wrong direction. The exact same training load that didn't affect your hormones a decade ago can suppress testosterone significantly more now. That's not you becoming weaker — that's the math of the system changing.

This is the clearest physiological reason why masters athletes often need to train differently than they did ten years ago — not because capacity has disappeared, but because the cortisol-testosterone ratio requires more deliberate management. More training is not the answer here. It's an even worse answer at 45 than it was at 28.

What this means practically: the ratio between training stress and recovery needs to be more conservative now than it was a decade ago. Easy days need to actually be easy. Recovery weeks need to be meaningful, not just slightly reduced load. The training-recovery balance that was sustainable at 32 may be quietly undermining your hormonal environment at 46 — even if the training feels manageable.

3. Sleep — More Important, Harder to Protect

A significant portion of testosterone production occurs during deep slow-wave sleep, when the hypothalamic-pituitary-gonadal (HPG) axis does the majority of its regulatory work. Even one week of sleep restriction measurably reduces testosterone in otherwise healthy people. This is not a marginal effect — it's one of the most direct levers available.

Here's the frustrating reality for this age group: sleep architecture naturally changes with age. Less deep slow-wave sleep. More fragmented sleep. More frequent nighttime waking. Often compounded by increased work and family demands, and for women specifically, perimenopausal sleep disruption that directly affects sleep quality during the same window when hormonal resilience is declining.

So the hormonal system needs quality sleep more than ever for testosterone production, at exactly the life stage when quality sleep is hardest to maintain and least likely to happen passively.

In your 20s, sleep largely took care of itself. At 45, it requires deliberate protection — and it cannot be out-supplemented. No stack of hormonal support compounds compensates for consistently poor sleep, because the hormonal production that supplements are meant to support happens during sleep.

Practical priorities: consistent sleep and wake times to anchor circadian rhythm; a genuine wind-down before bed rather than working or watching high-stimulation content until you fall asleep; protecting the sleep environment from noise and light; and for women in perimenopause, a direct conversation with a clinician about whether perimenopausal sleep disruption is worth addressing specifically.

4. Micronutrient Status — Zinc, Magnesium, and Vitamin D

Three micronutrients have direct relationships with testosterone production and bioavailability — and masters athletes are at elevated risk for insufficiency in all three, for reasons that compound each other.

Zinc is a required cofactor in testosterone biosynthesis. It's also lost through sweat — consistently and meaningfully under endurance training loads. Endurance athletes are depleting zinc every session, and dietary intake frequently doesn't keep pace with losses, particularly for athletes eating plant-forward diets that are lower in highly bioavailable zinc sources.

Magnesium affects testosterone bioavailability through its influence on SHBG (sex hormone-binding globulin). Higher SHBG binds more testosterone, reducing the free fraction that's biologically active. Adequate magnesium status helps maintain SHBG in a range that doesn't excessively bind the available testosterone. As with zinc, endurance training depletes magnesium through sweat, and dietary intake is frequently insufficient to compensate.

Vitamin D functions more like a hormone than a traditional vitamin — receptors for it are present in the testes and ovaries, directly in the tissue responsible for testosterone production. Deficiency is consistently associated with lower testosterone in research across multiple populations. And endurance athletes who train early in the morning or late in the evening, train heavily indoors during winter, or live at northern latitudes are at particularly elevated risk for suboptimal vitamin D status.

What's relevant for masters athletes specifically: absorption and baseline status of all three of these nutrients tends to decline with age independent of training — meaning the insufficiency risk from sweat losses and high training demand gets compounded by age-related changes in gut absorption and skin synthesis. This is a population where checking these levels is particularly worthwhile rather than assuming adequacy.

5. Body Composition — The Nuance That Matters Most After 40

Higher body fat — particularly visceral fat — is associated with lower testosterone because adipose tissue contains aromatase, the enzyme that converts testosterone to estrogen. That relationship is real and becomes more clinically relevant as visceral fat tends to increase with age, even without meaningful weight gain. Managing body composition is legitimate and worthwhile.

But the nuance that matters most for this age group cuts in the other direction: overly aggressive fat loss, layered onto a hormonal system with less buffer, suppresses testosterone through the energy availability mechanism above. Pursuing aggressive leanness at 45 through caloric restriction in a high-training-load context is one of the most reliable ways to suppress testosterone — and one of the most common patterns I see in this demographic.

The goal is not simply leaner. It's metabolically healthy — adequately fueled, well recovered, not in a chronic energy deficit in response to normal age-related body composition changes. A body composition that's slightly less lean than your 30-year-old self but hormonally functional and performing well is a better outcome than aggressively lean with suppressed testosterone, impaired recovery, and declining performance.

Targeted Supplementation — Once the Foundation Is Solid

Supplements are tools that support a well-managed system. They're not shortcuts around an unaddressed foundation — and that's true at any age, but the foundation has to be more deliberately maintained after 40 than it did when things functioned more automatically.

With the above in place, these are the compounds with the strongest rationale for masters athletes:

Vitamin D if levels are insufficient — which is common and worth confirming rather than assuming. Target serum 25-OH vitamin D between 50 and 80 ng/mL for performance, not just the 20 ng/mL floor of standard reference ranges.

Magnesium glycinate or malate at 300 to 400 milligrams of elemental magnesium daily — for recovery, sleep quality, and testosterone bioavailability through its effects on SHBG.

Zinc at 15 to 30 milligrams daily if intake or training losses suggest insufficiency — and for endurance athletes, they often do.

Ashwagandha (KSM-66 or Sensoril) at 300 to 600 milligrams daily has solid evidence for reducing cortisol and has shown positive effects on testosterone in populations under physiological stress — likely through the cortisol-suppression mechanism rather than direct testosterone stimulation. Given that managing the cortisol side of the cortisol-testosterone ratio matters more for masters athletes with smaller hormonal buffer, this is one of the more directly relevant compounds in this age group.

Where Precision Becomes Essential

Knowing that testosterone is low isn't sufficient information to act on effectively. You need to know how much is age-related baseline decline versus addressable suppression — and that requires specific testing: total testosterone, free testosterone, SHBG, and cortisol pattern.

In masters athletes, low testosterone is almost always a combination of both factors simultaneously. That's exactly why guessing is less effective at this age than it was at 25 — the picture is more complex, the margin is smaller, and the intervention needs to be calibrated to the actual pattern rather than a generic protocol.

When you address the upstream drivers — energy availability, training-recovery balance, sleep quality, micronutrient status — testosterone frequently improves meaningfully as a direct result, even accounting for the natural age-related decline happening in parallel. You're not reversing aging. You're removing the addressable suppression that's compounding it. And that distinction produces real, measurable results.

The Framework for Masters Athletes

To bring this together:

Energy intake that genuinely matches training load — accounting for the fact that the caloric restriction instinct that kicks in after 40 often works directly against hormonal function.

A training-recovery balance more generous than it needed to be a decade ago — because the cortisol-testosterone math has changed, not because capacity has disappeared.

Sleep protected deliberately rather than assumed to happen passively — because testosterone production depends on it and sleep quality at this life stage requires intention.

Micronutrient status confirmed rather than assumed — zinc, magnesium, and vitamin D all have direct relationships with testosterone and all carry elevated insufficiency risk in masters endurance athletes.

Targeted supplementation layered on top of that foundation — not instead of it.

This applies equally to men and women navigating this transition. Testosterone is not a male hormone. It's a performance hormone relevant at every stage of an athletic life, including this one.

Dr. Jason Barker is a naturopathic doctor with over 20 years of clinical experience working with endurance athletes. He is a two-time Ironman finisher and the founder of Natural Athlete Clinic. For individualized hormone testing and performance-focused protocols for masters athletes, visit naturalathleteclinic.com.