How to Naturally Increase Testosterone: An Evidence-Based Review

The short answer

For individuals with clinically low testosterone, certain lifestyle interventions—primarily weight loss in obese men and adequate sleep—can lead to modest but clinically meaningful increases. For those with normal levels, the impact of natural interventions is often negligible or unproven.

What the evidence actually shows

The most compelling evidence for naturally increasing testosterone centres on weight management and sleep optimisation. A prospective cohort study by Mulligan et al. (2014) involving over 2,000 men found that obesity was strongly associated with lower testosterone levels, and weight loss, particularly through bariatric surgery, led to significant increases. Similarly, a meta-analysis by Kumagai et al. (2012) demonstrated that weight reduction in obese men with hypogonadism consistently improved testosterone concentrations. Beyond obesity, chronic sleep deprivation has been linked to reduced testosterone. A small but impactful study by Leproult and Van Cauter (2011) showed that just one week of sleep restriction to 5 hours per night reduced daytime testosterone levels by 10-15% in healthy young men. Resistance training is also frequently cited, and while acute increases are well-documented (Vingren et al., 2010), long-term effects on basal testosterone are less pronounced in eugonadal men, though it can improve body composition which indirectly benefits hormonal balance.

Obesity is associated with a reduction in total and free testosterone in men, and weight loss interventions are an effective strategy to increase testosterone levels.

— Mulligan et al., Clinical Endocrinology, 2014

Where Harvard Health gets it right

Harvard Health consistently highlights the importance of core lifestyle factors, such as maintaining a healthy weight, engaging in regular physical activity (including resistance training), and ensuring adequate sleep, for overall hormonal health. They correctly identify that significant weight loss in obese men can lead to improved testosterone levels and that chronic sleep deprivation can negatively impact hormone production. Their advice often focuses on these fundamental aspects of health, which are supported by Tier I and II evidence, rather than promoting unproven supplements or extreme dietary changes.

Where the evidence is more nuanced

While Harvard Health provides sound advice on lifestyle, some popular claims around 'natural testosterone boosters' are often oversimplified or lack robust evidence. Many herbal supplements, such as fenugreek, ashwagandha, or tribulus terrestris, show mixed results in human trials, often with small sample sizes, short durations, or in specific populations (e.g., infertile men or those with existing deficiencies), making generalisation difficult. For example, some studies suggest ashwagandha may increase testosterone in stressed or infertile men (Mahdi et al., 2011), but its efficacy in healthy, eugonadal men is not consistently demonstrated. The impact of specific micronutrients, beyond correcting overt deficiencies (e.g., severe Vitamin D or Zinc deficiency), on testosterone in healthy individuals is also less clear than often portrayed.

Practical implications

For individuals concerned about low testosterone, the most evidence-based natural strategies involve prioritising weight management through diet and exercise, ensuring 7-9 hours of quality sleep per night, and managing chronic stress. Regular resistance training should be part of a comprehensive exercise regimen. Before considering any supplements, it is crucial to consult a healthcare professional to determine if testosterone levels are indeed low and to rule out underlying medical conditions. Focusing on foundational health habits offers the most reliable path to optimising hormonal balance and overall well-being, rather than relying on quick fixes.

Where reasonable people still disagree

• The clinical significance of small, transient increases in testosterone from certain supplements in otherwise healthy men, and whether these translate to improved health outcomes.
• The optimal dietary macronutrient ratios (e.g., fat intake vs. carbohydrate intake) for testosterone production, with conflicting evidence on specific recommendations.
• The precise mechanisms and long-term efficacy of adaptogenic herbs (e.g., ashwagandha) on testosterone levels in diverse populations, beyond specific clinical subgroups.