“How to increase size” means different things depending on what you’re trying to grow. Whether you want bigger muscles, more height, or are wondering about penile size, the answers are grounded in biology, and some are more within your control than others. Here’s what actually works, what doesn’t, and what the research says for each.
How To Build Bigger Muscles
Muscle grows when protein synthesis outpaces protein breakdown over time, creating a net positive protein balance. Three factors drive this process: mechanical tension (how hard the muscle works against resistance), metabolic stress (the burning fatigue from sustained effort), and muscle damage (micro-tears that trigger repair and growth). You can target all three with the right training approach.
The training parameters with the strongest evidence for muscle growth are moderate loads (60 to 80 percent of the heaviest weight you can lift once), 6 to 12 repetitions per set, 3 to 6 sets per exercise, and rest intervals around 60 seconds between sets. This combination generates significant metabolic stress while still providing enough tension to stimulate growth. Progressive overload, gradually increasing the weight or volume over weeks, is considered the single most important driver of long-term muscle gain.
The type of contraction matters too. Lowering a weight slowly (the eccentric phase) causes more muscle damage and adds length to muscle fibers. Lifting it (the concentric phase) primarily adds thickness. Training through a full range of motion with controlled eccentrics gives you both.
Protein and Nutrition
For most people doing resistance training, 1.4 to 2.0 grams of protein per kilogram of body weight per day is enough to maximize muscle growth. For someone weighing 80 kg (about 176 pounds), that’s 112 to 160 grams of protein daily. If you’re in a calorie deficit while trying to preserve muscle, you may need even more: up to 2.3 to 3.1 grams per kilogram per day.
Eating enough total calories also matters. You can’t build significant new tissue without the raw materials. A modest calorie surplus of 200 to 500 calories above maintenance, combined with adequate protein, provides the energy and amino acids your body needs to add muscle without excessive fat gain.
Creatine and Cell Volume
Creatine monohydrate is the most well-studied muscle-building supplement available. Part of its effect on size comes from drawing water into muscle cells, increasing intracellular volume. This cell swelling isn’t just cosmetic: the increased osmotic pressure is itself considered a stimulus for cell growth. Studies consistently show increases in skeletal muscle mass, total body water, and intracellular water in people taking creatine compared to placebo. A typical dose is 3 to 5 grams daily.
Sleep and Growth Hormone
Growth hormone secretion spikes during deep sleep (slow-wave sleep), and this surge is largely sleep-dependent. Cutting sleep short or sleeping poorly reduces that hormonal signal. For anyone trying to build muscle, consistently getting 7 to 9 hours of quality sleep supports the recovery and hormonal environment that makes training productive.
How To Maximize Height
Height is primarily determined by genetics, but nutrition and hormonal health during childhood and adolescence play a meaningful role. Long bones grow at the growth plates (epiphyseal plates), and once these plates close after puberty, linear growth stops permanently. No supplement, exercise, or device can increase height in adults with closed growth plates.
For children and adolescents still growing, several nutrients are essential for reaching full genetic height potential. Protein deficiency impairs bone growth even when total calorie intake is adequate. Calcium deficiency disrupts the structure of the growth plate itself, causing focal breaks. Magnesium deficiency can reduce growth plate width by up to 33 percent and decrease the number of cartilage cells responsible for bone lengthening. Zinc directly affects growth hormone and its downstream signals, influencing bone growth rate, growth plate thickness, and cell development. Iodine deficiency reduces thyroid hormone production, which slows linear bone growth. Vitamins C and D are both critical: vitamin C deficiency impairs bone growth (and in severe cases causes scurvy), while vitamin D deficiency distorts the structure and mineral content of growth plates.
One nutrient to be cautious with is vitamin A. While necessary in normal amounts, excess vitamin A can actually cause premature fusion of the growth plates, cutting growth short.
The practical takeaway: a nutrient-dense diet with adequate protein, calcium, zinc, magnesium, and vitamins C and D gives growing children the best chance at reaching their full height. Restrictive caloric diets during childhood and adolescence can permanently compromise bone growth.
Penile Size: What’s Normal
A systematic review of 75 studies covering nearly 56,000 men found the average erect length is about 13.9 cm (roughly 5.5 inches). Flaccid length averages 8.7 cm (about 3.4 inches), and stretched length (which correlates with erect length) averages 12.9 cm. Individual measurements across studies ranged widely, from 9.5 cm to 16.8 cm erect, which means there’s a broad range of normal.
Most men who worry about size fall well within the statistical norm. True micropenis, a medical condition, is defined as more than 2.5 standard deviations below the mean and is rare.
What Works for Penile Size (and What Doesn’t)
Medical traction devices are the only non-surgical approach with clinical trial support. In a randomized controlled trial, a traction device used for 30 to 90 minutes daily produced an average gain of 1.6 cm (about 0.6 inches) in penile length over six months, compared to just 0.3 cm in the control group. Adverse events were mild and temporary. Among users, 87 percent said they would repeat the therapy and 93 percent would recommend it to others. These devices are typically prescribed for conditions like Peyronie’s disease or post-surgical recovery, not cosmetic use in otherwise healthy men, and results are modest.
Enhancement Pills Don’t Work
Over-the-counter supplements marketed for male enhancement have no clinical evidence supporting permanent size increases. The FDA has repeatedly warned that many of these products are contaminated with hidden pharmaceutical ingredients, making them a direct health risk. These products are often falsely advertised as dietary supplements or “all-natural” treatments. The FDA’s published list of contaminated products covers only a small fraction of what’s on the market, meaning an unlisted product is not necessarily safe. No pill can change the structural anatomy of the penis.
Surgery Carries Serious Risks
Surgical enhancement (phalloplasty) carries complication rates as high as 76.5 percent in published data. Among 139 patients in one study, 15 percent required unplanned reoperation, nearly 8 percent needed blood transfusions, and about 6 percent were readmitted to the hospital. These are major complications for what is typically an elective procedure. Ligament-release surgeries can add modest visible length when flaccid but may reduce erection angle, and fat injection for girth often results in uneven absorption over time.
The Common Thread: What You Can Control
Across all types of “size,” the controllable factors come down to a few basics. Consistent resistance training with progressive overload builds muscle. Adequate nutrition, particularly protein, supports both muscle growth and (during youth) bone development. Quality sleep enables the hormonal environment needed for tissue repair and growth. For penile size, most men are already normal, and the few interventions with any evidence offer modest results at best.
Where you have real leverage is muscle. Unlike height (which has a hard deadline) or penile size (which is largely fixed by anatomy), skeletal muscle responds to training stimulus throughout your entire life. The combination of progressive resistance training, 1.4 to 2.0 grams of protein per kilogram daily, creatine supplementation, and consistent sleep is the most evidence-backed path to measurably increasing your physical size.