Does intermittent fasting increase testosterone levels?

Does intermittent fasting increase testosterone? The short answer is that there is no good evidence it reliably does. Small human studies suggest testosterone can fall in some lean, active men following time-restricted eating, while findings in other fasting settings are mixed. For men over 50, the evidence is especially thin. A fasting schedule may help some people manage eating and weight, but it is not a proven testosterone-boosting method. The total food, sleep, training, health conditions, and medicines involved matter too.

What the studies actually say

Intermittent fasting can mean several different things: eating within a daily window, fasting on selected days, or observing Ramadan, when food and drink are avoided from dawn to sunset and meals shift to nighttime. These patterns are not interchangeable. Study participants, fasting duration, calories, and blood-draw timing also differ, making a simple yes-or-no conclusion difficult.

A review of human trials found that intermittent fasting reduced testosterone in lean, physically active young men in the limited studies available. It did not find a change in sex hormone-binding globulin, a protein that carries testosterone in the blood. The authors stressed that very few studies had examined men, so the findings cannot establish what happens for most men or for older adults. (Cienfuegos et al., 2022, PMID 35684143)

A small randomized study followed 20 healthy men doing resistance training for a year. The time-restricted group ate three meals in an eight-hour window; the comparison group ate three meals over a longer day. Testosterone and body mass were lower in the time-restricted group by the end, while some metabolic markers improved. This study was small, and the fasting group also reduced its daily energy intake. It cannot tell us whether the clock window itself, eating less, or a combination explains the difference. (Moro et al., 2021, PMID 34649266)

Ramadan fasting research does not point in one direction. One study of 52 healthy male students aged 18 to 24 found lower testosterone later in Ramadan, but those participants were much younger than the men this article is for. A 2024 review and meta-analysis of Ramadan studies in healthy adults did not find a significant overall change in testosterone. Meal timing, sleep, hydration, and study methods vary across Ramadan research. (Mesbahzadeh et al., 2005, PMID 16761684) (Poursalehian et al., 2024, PMID 38781203)

Evidence	What it suggests	Main limit
Review of human fasting trials	Some young, lean, active men had lower testosterone	Few male studies; not focused on older men
12-month eating-window study	Testosterone fell in the time-restricted group	Only 20 men; intake also fell
Ramadan studies	Individual studies and pooled findings differ	Special schedule and varied populations

Taken together, these findings do not support fasting as a reliable way to increase testosterone. They also do not show that every man who fasts will have a meaningful decline. A blood level can move with time of day, food intake, sleep, illness, and other factors. A single result is not a full picture of a person’s health.

Why a fasting schedule can affect the result

The body responds to the overall conditions created by a diet, not just the clock. If an eating window helps someone reduce excess weight gradually while still getting enough nourishment, that may support general metabolic health. If fasting leads to very low intake, fatigue, poor sleep, or difficulty recovering from exercise, it may be a poor fit. The studies above do not show that fasting itself is a testosterone treatment.

Testosterone also varies naturally. Levels are generally higher earlier in the day and can be affected by a disrupted night, temporary illness, and some medicines. If a result seems low, tell your clinician how and when the blood test was taken, and ask whether repeat testing is appropriate. Do not try to interpret a lab result from a fasting experiment on your own.

If your main goal is weight management, a sustainable eating pattern matters more than a specific fasting window. Our guides to intermittent fasting for men over 50, belly fat and testosterone, and why belly fat will not go away cover related questions. For a broader explanation of abdominal fat, see what visceral fat is.

Warning signs: when to talk with a doctor

Arrange medical advice if you have a persistent drop in sexual desire, fewer spontaneous or morning erections, ongoing erection problems, unexplained loss of strength, or unusual fatigue that does not improve. These symptoms can have many causes; they do not prove that testosterone is low. New or worsening symptoms deserve medical care.

Seek urgent care for severe symptoms such as chest pain, fainting, confusion, or severe weakness, especially if they occur while fasting. If you have diabetes, kidney or heart disease, a history of disordered eating, or take medicines that affect blood sugar or blood pressure, discuss any major change in meal timing with your clinician first. Do not change or skip medication to fit a fasting schedule.

Habits to prioritize before supplements

If you want to support energy, strength, and healthy weight, start with routines you can sustain. These are useful for overall health; they are not guaranteed to raise testosterone.

• Protect sleep. Keep a regular bedtime and wake time when possible. If you snore heavily, wake gasping, or remain sleepy despite enough time in bed, ask about it at a medical visit. Sleep disruption may affect how you feel and can complicate hormone testing.
• Keep resistance exercise consistent. Use a plan appropriate to your joints and fitness, and allow recovery between hard sessions. Strength training can help preserve function as you age. Avoid stacking a restrictive eating window on top of training if you are not recovering well.
• Eat enough and choose nourishing meals. Build meals around vegetables or fruit, fiber-rich foods, and satisfying protein sources. If a time window makes it hard to eat enough or maintain strength, widen it or choose a different routine with professional guidance.
• Aim for gradual weight change if needed. Men carrying excess weight may find that manageable changes in food portions and activity help with weight goals. Fasting is only one possible structure. Avoid crash diets and routines that leave you weak or preoccupied with food.
• Review alcohol, stress, and medicines. Bring a current medication and supplement list to your clinician. Alcohol, stress, illness, and some prescriptions can affect sexual function, sleep, or energy, and deserve an individual conversation.

For practical approaches to activity, read strength training for men over 50. If abdominal weight is the concern, how to lose belly fat after 50 and belly fat and heart health may help you plan realistic next steps.

What about supplements?

A supplement marketed to increase testosterone is not a substitute for finding out why symptoms are happening. Research on an ingredient does not automatically apply to every blend, and products vary in their disclosed amounts and evidence. Stark Verve uses strict scoring; a higher score is not a promise of a hormone change. Results vary. Talk to your doctor before using a supplement, especially if you take medication or have new or worsening symptoms.

If you are comparing weight-focused products, start with our weight supplements comparison guide and see the LeanBiome review. These pages assess labels and available research; they do not establish that a product raises testosterone.

Next step

If you are considering fasting mainly for weight management, read intermittent fasting for men over 50 next. It can help you think through meal timing and fit before choosing a routine.

Frequently asked questions

Does intermittent fasting increase testosterone?

Current human evidence does not show a reliable increase. Some limited studies found lower levels in certain men, and other findings are mixed.

Can intermittent fasting lower testosterone?

It may lower measured testosterone in some settings. A review reported decreases in lean, active young men, and one small year-long study found lower levels in men using an eight-hour eating window. Evidence is not sufficient to predict an individual response.

Is fasting safe for men over 50?

It depends on health, medicines, and how restrictive the schedule is. Discuss fasting with a clinician if you have a chronic condition or use medicines affected by meal timing. Stop and seek advice if you feel unwell.

Should I fast before a testosterone blood test?

Follow the instructions from the clinician or laboratory ordering the test. Tell them about fasting, sleep disruption, and medicines rather than changing your routine without guidance.

What should I do if I think my testosterone is low?

Talk with a healthcare professional about persistent symptoms and whether testing is appropriate. Do not diagnose yourself from symptoms alone or begin a supplement based on an online claim.

Results vary from person to person. Talk to your doctor, especially if you take medications. New or worsening symptoms deserve medical care.