Testosterone Optimisation, Part 1: The Nutritional Foundation

The internet is full of testosterone advice. Eat more red meat. Take zinc. Avoid soy. Most of it isn't wrong, exactly - it's just shallow. It treats testosterone optimization as a checklist of isolated hacks rather than what it actually is: a systems problem that demands a systems approach.

This series bridges the gap between optimization culture and clinical medicine. We're not chasing supraphysiological levels or selling miracle supplements. We're building a comprehensive framework (biological, psychological, environmental, and social) that supports your body's natural testosterone production and metabolism. Evidence-based, but not afraid to challenge conventional thinking where the evidence warrants it.

We start where it matters most: what you eat. Not just which foods, but how much, in what proportions, and why the details matter more than most people realize.

Energy Availability: The Missing Conversation

Before we talk about macronutrients, we need to talk about total calories, because chronic undereating is one of the most common and most overlooked testosterone suppressors in health-conscious men.

It's a familiar pattern: a man "eats clean," trains hard, and tracks his macros, but runs a sustained caloric deficit without realizing it. The body interprets this as a survival threat and downregulates reproductive hormones accordingly. Testosterone drops, thyroid slows, cortisol rises. You can have the cleanest diet in the world, but if you're not eating enough, your endocrine system will pay the price.

This doesn't mean you should overeat. It means that total energy intake needs to match total expenditure, including training, daily activity, and the baseline demands of keeping your body running. For most active men, this means eating at or slightly above maintenance, and being deliberate and time-limited when cutting. Crash diets and prolonged aggressive deficits are hormonal sabotage.

The important exception here is men who are overweight or obese. Excess body fat increases aromatase activity, promotes insulin resistance, and drives chronic low-grade inflammation, all of which suppress testosterone. For these men, a controlled caloric deficit to reduce body fat is one of the most effective interventions for improving testosterone levels. The key word is controlled: moderate deficits that preserve muscle mass and don't tank energy or mood. The goal is sustainable fat loss, not a crash diet that trades one hormonal problem for another.

Macronutrients

Dietary Fat

Testosterone is a steroid hormone, and adequate dietary fat is essential for its production. Fat carries fat-soluble vitamins critical for hormonal health (D, K2, A, E) and provides caloric density that helps maintain energy availability. Research consistently shows that very low-fat diets (below 20% of calories) significantly reduce testosterone levels.

The optimal approach includes a balance of saturated, monounsaturated, and polyunsaturated fats at approximately 30–40% of total calories. Saturated and monounsaturated fats appear particularly relevant for testosterone. Sources include egg yolks, grass-fed butter, olive oil, avocados, fatty fish, and high-quality red meat. Individual responses to saturated fat vary depending on genetics and metabolic context.

Omega-3 fatty acids from fish oil, salmon, sardines, and mackerel reduce inflammation and may improve testosterone-to-cortisol ratios. Aim for about 2–3 grams of combined EPA and DHA daily. More might be needed in some cases. Monitor your response through fatty acids testing, specifically your Omega-3 Index, aiming for 8–12%. Look for a test that measures omega-3s in red blood cells, such as OmegaQuant.

Protein

A protein intake of 1.6–2.2 grams per kilogram of body weight supports muscle protein synthesis, recovery, and satiety. While some may consider this range on the higher end, it represents a reasonable target, particularly when optimizing body composition. That said, extremely high protein intake at the expense of adequate fats and carbohydrates can be counterproductive for testosterone optimization.

It's worth being clear about the mechanism: protein doesn't directly stimulate testosterone the way fat or certain micronutrients do. Its value is indirect but substantial. Adequate protein supports lean mass, improves body composition, and reduces muscle loss during any fat loss phase, all of which create a more favorable hormonal environment over time.

Animal proteins offer distinct advantages: complete amino acid profiles, B vitamins, highly bioavailable iron, zinc, and the dietary fats that support hormonal health. Plant-based diets can work but require more careful planning and supplementation to achieve similar outcomes. For testosterone optimization, whole food animal sources like eggs, fatty fish, grass-fed meat, and organ meats are the most straightforward path.

Carbohydrates

While low-carb diets have gained popularity over the last 10–20 years, chronically low carbohydrate intake can suppress thyroid function and increase cortisol, particularly in active individuals. Carbohydrates support intense training, promote better sleep, and help regulate the stress response.

The key is matching carbohydrate intake to activity level. Active men doing resistance training should consume roughly 3–5 grams per kilogram of body weight, focusing on whole food sources like potatoes, rice, oats, fruits, and vegetables. This is especially important post-workout, since carbohydrate intake helps lower cortisol and supports recovery.

A note on all of the above: these targets assume a reasonably healthy metabolic baseline. Men with type 2 diabetes, metabolic syndrome, or significant gut issues may need different starting points, and working with a knowledgeable practitioner becomes important.

Micronutrients: The Big Three

Many men in the modern world are deficient or insufficient in at least one of these. If you address nothing else on the micronutrient front, address these first.

Vitamin D

Vitamin D functions more like a steroid hormone than a vitamin. Receptors for vitamin D are expressed in testicular tissue, and adequate levels are associated with higher testosterone production. The majority of men have insufficient levels, particularly those living in northern latitudes or spending minimal time outdoors. Target blood levels of 40–60 ng/mL through sun exposure (15–30 minutes of midday sun on large body surface areas) and supplementation of 2,000–5,000 IU daily, depending on baseline levels. This is a safe and relatively conservative range. Test your levels at least annually.

Magnesium

Magnesium is involved in over 300 enzymatic reactions (actually more like 600+) and appears to increase both free and total testosterone. It also improves sleep quality and buffers against the negative effects of stress. Target 400–600 mg daily (or 5–10 mg per kilogram of body weight if very active). In practice, most men fall short through diet alone, partly because modern food processing and soil depletion have reduced the magnesium content of many staple foods. Supplementation is worth considering for most, if not all, men.

Supplemental magnesium glycinate (200–400 mg, 30–60 minutes before bed) is a good option for those falling short, with the added benefit of supporting sleep quality. One important note on magnesium supplements: always check the elemental magnesium content, not just the total weight of the compound. A capsule labeled as 1,000 mg of magnesium bisglycinate typically delivers only about 100 mg of actual elemental magnesium. The upside is that the remaining 900 mg is glycine, an amino acid that independently supports sleep and relaxation, so 2–4 capsules gives you both a meaningful magnesium dose and 1,800–3,600 mg of glycine as a bonus.

Zinc

Zinc is directly involved in testosterone synthesis and protects against its conversion to estrogen via the aromatase enzyme. Deficiency is common, particularly in men following plant-based diets and athletes who lose zinc through sweat. Target 15–30 mg daily from whole food sources like oysters (the most zinc-dense food), red meat, pumpkin seeds, and cashews. Supplementation can be beneficial for those with deficiency symptoms, but excessive zinc interferes with copper absorption. Continuous supplementation should always be monitored, especially at higher doses.

The Supporting Cast

These won't make or break your testosterone levels, but they round out the nutritional picture, and several have outsized importance for specific individuals.

Vitamin K2 works synergistically with vitamin D and appears to stimulate testosterone production in Leydig cells. It also directs calcium to bones rather than soft tissues, making it particularly important for men supplementing high-dose vitamin D. Supplementation of 100–200 mcg daily (MK-7 form) is reasonable, increased to 400–600 mcg for those aiming for higher vitamin D levels. Best sources: natto, aged cheeses, egg yolks from pasture-raised hens, and grass-fed butter.

Selenium supports thyroid function and protects testicular tissue from oxidative damage, making it especially relevant for men with suboptimal thyroid markers. Direct supplementation of 75–100 mcg daily provides a safe dose. Be careful: many commercial products contain 200 mcg per serving, which is typically too high for long-term use. Selenium becomes toxic in excess, with chronic intake above 400 mcg potentially causing selenosis.

B Vitamins - particularly B6, B12, and folate - support dopamine synthesis and the methylation pathways involved in hormone metabolism. Organ meats, nutritional yeast, eggs, and leafy greens are your best sources. A high-quality B-complex can fill gaps.

Boron has been shown to reduce SHBG, which can increase free testosterone. The dose used in studies is 6–10 mg, but this effect appears transient. I don't consider it a major lever for testosterone optimization, though it may have other health benefits (read: Nothing Boring About Boron, Pizzorno 2015).

Gut Health: The Overlooked Axis

Your gut microbiome plays a direct role in hormone metabolism, particularly estrogen clearance. An enzyme called beta-glucuronidase, produced by certain gut bacteria, can reactivate estrogen that the liver has already processed for elimination. Gut dysbiosis can mean your body recirculates estrogen rather than excreting it, shifting the testosterone-to-estrogen ratio in the wrong direction.

Intestinal permeability, often called "leaky gut," contributes to systemic inflammation, which suppresses testosterone production through multiple mechanisms. Practical takeaways: consume fermented foods regularly (sauerkraut, kimchi, yogurt, kefir), eat adequate fiber (30–40 grams daily from vegetables, fruits, and legumes if tolerated) to support microbial diversity and healthy bowel habits and elimination, and minimize the processed foods and alcohol that damage gut integrity.

Meal Timing and Eating Patterns

Given the popularity of intermittent fasting, this is worth addressing. Extended daily fasting windows (16+ hours) can raise cortisol and increase SHBG, both of which suppress free testosterone, particularly in active men who are already training hard. Men focused on testosterone optimization should be cautious about combining prolonged fasting with intense training and caloric restriction simultaneously. That's three stressors stacked on top of each other.

A more practical approach for most men: eat within a reasonable window (10–12 hours), don't skip meals around training, and prioritize adequate post-workout nutrition, particularly carbohydrates and protein. Save the aggressive fasting protocols for periods when testosterone optimization isn't the priority.

Foods and Substances to Minimize

Alcohol is the big one. Even moderate consumption suppresses testosterone production, impairs sleep architecture, and increases aromatase activity, converting testosterone to estrogen. Limit to 2–3 drinks per week maximum. If testosterone optimization is a serious goal, less is genuinely better here, and no alcohol is always best.

The nuanced ones: Soy isn't the enemy it's been made out to be. Meta-analyses show no significant effect on testosterone at normal dietary intake, though very high consumption may have mild estrogenic effects. Industrially refined seed oils undergo heavy processing (chemical solvents, high heat, bleaching) that degrades their polyunsaturated fats, and their high omega-6 content can contribute to an imbalanced omega-6 to omega-3 ratio that promotes inflammation. That said, they've been overly vilified in some circles, and the dose and context matter. Licorice root contains glycyrrhizin, which significantly suppresses testosterone, so avoid it as a regular habit, especially in large amounts.

The Bottom Line

If all of this feels overwhelming, don't try to implement everything at once. Start with a few high-leverage steps: cut the alcohol, eat enough calories with an emphasis on whole foods (or if you're carrying excess weight, begin a gradual and sustainable fat loss phase), and get your vitamin D levels tested and supplement accordingly. Those three steps will make a meaningful difference. Everything else in this article builds on that foundation.

Next up in Part 2: we cover two of the most important lifestyle levers for testosterone: how you train and how you sleep.