Testosterone | LIN28B (rs7759938)

LIN28B and Testosterone: What Your Genotype May Mean for Puberty and Hormone Health

Testosterone influences physical development, muscle mass, bone strength, energy, mood, and reproductive health in people of all sexes. The LIN28B gene helps regulate timing of puberty and hormone signaling in the neuroendocrine axis. Variations at rs7759938 in LIN28B are linked to differences in pubertal timing and baseline testosterone levels in adulthood.

This article explains what each genotype at rs7759938 has been associated with, practical ways to support healthy hormone balance, and when to talk to your healthcare provider. PlexusDx does not provide medical advice. Use this information to learn about genetic predispositions only and always consult your healthcare provider before making clinical decisions.

How to read this result

Effect allele: C (described below as the effect allele in this report)
rs7759938 location: LIN28B gene
Implications: associations are probabilistic and represent one factor among many that influence hormones — environment, lifestyle, age, body composition, medications, and other genes matter.

General recommendations to support healthy hormones

Diet: emphasize whole foods, balanced macronutrients, adequate protein (about 0.8–1.2 g/kg body weight for general maintenance; more for strength training), healthy fats (including omega-3s), and plenty of fruits and vegetables for vitamins and antioxidants.
Exercise: combine resistance training 2–4 times per week to support muscle mass and bone strength with moderate aerobic activity 150 minutes per week.
Sleep: prioritize 7–9 hours nightly with regular sleep-wake times to support endocrine rhythms and testosterone production.
Stress management: reduce chronic stress through mindfulness, breathing exercises, counseling, or regular physical activity to lower cortisol-driven hormone disruption.
Alcohol and nicotine: limit alcohol intake and avoid smoking and recreational drug use, which can negatively affect hormone levels.
Body composition: maintain a healthy body fat percentage; both very low and very high body fat can disrupt normal hormone balance.

Genetic interpretations

Two effect alleles (CC) — two copies of the C allele

If you have the CC genotype for rs7759938, you carry two copies of the effect allele. This genotype is associated with later onset of puberty and lower baseline testosterone levels in adulthood. LIN28B helps regulate the timing of puberty and influences the neuroendocrine axis that controls hormone balance.

What you may have experienced and what this means now:

Likely average or later pubertal development compared to people with T alleles
Lower baseline free testosterone in adulthood is more likely compared to some other genotypes
Lower testosterone may modestly influence muscle mass, bone density, energy, and metabolic patterns

Practical steps to support hormone health:

Strength training: prioritize progressive resistance to preserve or build lean mass and stimulate anabolic signaling
Protein and micronutrients: ensure adequate protein, vitamin D, zinc, magnesium, and healthy fats to support hormone production
Sleep and recovery: emphasize consistent sleep and avoid late-night light exposure to support circadian regulation of hormones
Monitor symptoms: track energy, libido, changes in muscle or bone strength, menstrual irregularities (if applicable), or new skin changes
Consider baseline labs: if concerned, discuss checking morning total and free testosterone, SHBG, LH, FSH, and if relevant, estradiol, vitamin D, and basic metabolic panel

When to consult your healthcare provider: if you have persistent fatigue, sexual dysfunction, unexplained muscle loss, bone fragility, or a history of significantly delayed puberty, seek evaluation for possible hormonal or endocrine causes.

One effect allele (CT) — one C and one T

If you have the CT genotype for rs7759938, you carry one copy of the effect allele. This profile is associated with moderately later puberty onset and lower baseline testosterone levels compared to those with two T alleles. LIN28B helps regulate pubertal timing and the neuroendocrine axis.

What you may have experienced and what this means now:

Possibly slightly later physical development during adolescence
Potential for somewhat lower free testosterone in adulthood compared to TT individuals
Small effects on muscle mass, bone density, and metabolic function are possible but are influenced by lifestyle

Practical steps to support hormone health:

Combine resistance training with adequate protein intake to support muscle and bone
Ensure sufficient dietary fat (including omega-3s) and key minerals like zinc and magnesium
Prioritize consistent sleep and stress management to reduce cortisol interference with sex hormones
Regular health maintenance: consider bone health screening if other risk factors exist and discuss targeted blood testing with your provider if symptoms arise

When to consult your healthcare provider: discuss testing if you experience troubling symptoms such as persistent low energy, loss of libido, significant bone or muscle loss, or concerns about reproductive health.

No effect alleles (TT) — two T alleles

If you have the TT genotype for rs7759938, you carry two copies of the non-effect allele. This genotype is associated with the latest expected onset of puberty and lowest baseline testosterone levels compared to other variants described in this report. LIN28B regulates pubertal timing and hormone balance through the neuroendocrine axis.

What you may have experienced and what this means now:

Likely average or later physical development during adolescence
Lower baseline testosterone in adulthood compared to other genotypes in this set
Potential impact on muscle mass, bone density, energy levels, and reproductive hormone patterns

Practical steps to support hormone health:

Emphasize resistance training and weight-bearing exercise to protect bone and muscle
Optimize nutrition: adequate protein, calcium, vitamin D, and minerals to support skeletal and hormonal health
Keep routine health checks: consider periodic assessment of testosterone, SHBG, bone density screening if other risk factors are present
Address modifiable risks such as high alcohol intake, smoking, and sedentary behavior

When to consult your healthcare provider: if you have symptoms suggesting low testosterone or late-onset puberty history that raises concern, seek personalized evaluation and possible blood testing.

Diet, supplement, and lifestyle considerations (practical list)

Protein: include quality protein at each meal to support muscle, e.g., lean meats, fish, dairy, legumes, or plant proteins
Healthy fats: include sources of monounsaturated and omega-3 fats such as olive oil, nuts, seeds, and fatty fish
Vitamin D: maintain adequate levels through sensible sun exposure and supplementation if deficient; vitamin D supports bone and possibly testosterone levels
Zinc and magnesium: obtain through diet (seafood, nuts, seeds, green vegetables) and supplement if clinically indicated
Strength training: at least 2 sessions weekly focusing on major muscle groups
Sleep hygiene: 7–9 hours nightly with regular schedule
Limit alcohol and tobacco to protect endocrine and bone health

Suggested blood tests to discuss with your provider

Morning total testosterone and free testosterone
Sex hormone binding globulin (SHBG), LH, FSH
Estradiol if clinically indicated
Vitamin D (25-OH), fasting glucose, lipid profile
DEXA scan for bone mineral density when risk factors for low bone mass exist

Remember, genetic results describe tendencies, not destiny. Lifestyle, environment, age, other genetic factors, and medical history play important roles. PlexusDx provides educational information about genetic predispositions only and does not provide medical advice. Always consult your healthcare provider to interpret results in the context of your full medical history and before starting any treatments, supplements, or major lifestyle changes.